Coolboats to admire

[dolphinmaster]

I like the accommodations on Rocket Science.  A loosened up version of the interior of a 40 footer: aft cabins big enough to warrant the name, a big galley, a spacious saloon, chart table big enough for a full paper chart.

One thing I find strange, though, is the sinks in both the aft cabins... seems like an odd thing to prioritize in the limited space of a private cabin.  So everyone can brush their teeth at the same time?

View attachment 478627 View attachment 478626

Maybe they like to tidy up after fooling around   ( That's the literal wording for what Snags might say

 

[dolphinmaster]

From here: http://svrocketscience.com/technical-details/

Model: Riptide 55 Designer: Paul Bieker. Built at Shaw boats in Aberdeen, WA. Finishing and commissioning were done at Seaview West and CSR in Seattle.

Construction: Carbon fiber/glass/duracore balsa /nomex composite

Design Objectives – The RipTide 55 is designed to be the next generation
of club racing and long distance cruising yacht. Rather than a highly
specialized cruising yacht like the Sun Deer or Deer Foot series, the
emphasis is on an all around boat that can be used for club racing and
coastal cruising but is also engineered and capable of long ocean
passages. This is the same concept that Nautor and Baltic have used for
years that has preserved the value of their boats over a sustained period
of time. However unlike Nautor and Baltic who have not updated their use
of materials or available technologies, the Riptide 55 incorporates very high-tech
materials and proven design concepts that have proved themselves
over the years at the highest level of offshore ocean racing.
Extensive use of carbon fiber, kevlar and honeycomb cores has produced a boat with ultralight
displacement ratios and with the strength and integrity that is far in
excess of even the stoutest cruising boats. From the comments below you
will see how using these materials to lower the center of gravity has
produced a very light boat that has an extremely seakindly motion and very
little tendency to pound. Pounding when going to windward has been the
Achilles heel of the last generation of light weight cruising boats. Some
manufactures have even tried to side step this problem by installing large
engines and focus on the virtues of motoring to windward.

Design and Engineering Process – The RipTide 55 used a paperless design
and engineering process. The design, drawing and engineering process was
integrated into one process and was all done on the computer. It is not
uncommon in today’s design world to have one person draw the lines by hand
then turn their work over to another person who then adds the interior,
another person then takes those drawings and inputs them into the computer
after all this is done the plans are then turned over to a structural
engineer who often takes a “cookbook” approach to figuring out panel,
stringer and laminate scantlings. The designer, Paul Bieker, did all the
CAD work, finite element analysis and engineering. Paul is known for his
engineering expertise in structural trouble shooting on large ships and
yachts. Paul is also known for producing this country’s fastest
International 14 Designs and Paul has logged over 50,000 offshore miles
cruising. Paul is one of the few designers that has the ability to
integrate the engineering and design process all in a paperless computer
design that truly has everything meeting in three dimensions. This process
is often used on the large commercial ships but is rarely seen in the
world of yacht design. In addition Paul is on the leading edge of monohull
development by his dedication to the International 14 class which has
pioneered most of today’s speed innovations such as articulating
bowsprits, flexible rigs, and large roached mainsails. Paul also is part of the design team for the BMW/Oracle team, with the latest example of his work being the design of the lifting foils for the AC72 catamaran being used in the America’s cup defense.  Paul’s intuitive
design insights and fundamental understanding of today’s modern materials
has produced a truly unique yacht which is not available anywhere else and
the concepts of which could not be easily reproduced without the subtle
knowledge of how these materials were used.

Structural Integrity – In order to be a truly seaworthy yacht the Riptide
55 had to be able to endure years of ocean abuse and be able to sustain
hull integrity in the case of hitting a log or container at 14 knots or
hitting a rock with the keel at 12 plus knots. In order to accomplish
these requirements true base line engineering was used that combined
finite element analysis along with a panel testing program that field
tested the computer assumptions.
What was apparent from the polar predictions was the extreme speeds that a
yacht like the Riptide 55 can generate. For this reason it was decided not
to use the ABS guidelines for yachts, those standards did not adequately
address the speed potential of today’s modern craft. Instead the standards
selected were ABS slamming standards for high speed military craft and Det
Norske Veritas standards for high speed offshore motor craft. Using these
standards a loading of 7.5 PSI was arrived at, approximately double ABS
standards. To put this number into perspective, the RT55 could slam on an
area of a little over a square meter in front of the keel for the life of
the boat. These are extreme conditions found when flying off of waves in
the worst conditions. In order to keep the panel from flexing and to
provide fatigue resistance the panel specification was set at 40 PSI so
that the maximum loading was not to exceed 20% of the panels specified
breaking strength. A laminate schedule was modeled in the computer and
then panels were made by the builder and tested by Gugeon Brothers to see
if they met the specifications. The panel for the hull bottom has a core
of 1″ Baltec Duracore and skins of carbon fiber and unidirectional glass.
Upon testing of these panels a breaking strength of 54 PSI was found, well
in excess of the 40 PSI specification and a number realized only in high
speed power craft. Even more important in a panel test of 400,000 flexing
cycles of 25 PSI ( half the panels breaking strength and over three times
the required extreme specification) no softening was found. This is
unprecedented. The next time a manufacturer makes claims about their
hull’s strength ask to see the documentation for the underlying
engineering assumptions, the finite element analysis and the panel testing
data to back up the assumptions in the finite element analysis.
The question becomes why make the panel so strong. The answer is that the
panel had not only to sustain the slamming conditions at sea but with all
the debris in the modern ocean it had to be able to sustain a collision
with a solid object such as a log or a cargo container that had been lost
off of a deck of a ship. Keep in mind that the RT55 is capable of speeds
over 20 knots. The deceleration from such a hit would be dangerous enough
without having to worry if the boat would disintegrate. As further
protection from such a catastrophic situation a kevlar crash barrier
laminate was added in the center 30 inches of the hull forward of the
keel. This laminate is next to the core on both sides underneath the
carbon fiber. This is counter to present conventional thinking which would
put the kevlar on the outer laminate because of its abrasion resistance.
What was found in the panel testing at Guegon was that the kevlar in a
catasrophic hit would shatter on the outside skin because of its
brittleness and the stiffness of the underlying core and laminates and
even potentially holed. Dropping heavy metal balls on the laminate it was
found that while the glass and carbon skins were breached that the
laminate hung together because the kevlar as the last line of defense
works in tension to absorb the energy of the of the object and while
delamination occurred the laminate was not breached. As a belt and
suspenders approach to hull integrity, integral sewage, fuel and water
tanks form a double bottom in the critical areas of the boat in case of a
grounding on a beach or a reef. The RT55 also has forward and aft semi
water tight compartments to increase survivability in the case of a
collision.
While there was much attention to the hull and its integrity, the decks
had many requirements put on them. They had to sustain heavy seas and
provide a stiff lid to the whole boat. The deck panels on the RT55 are
carbon fiber skins over a honeycomb HRT type core and then a 4 oz. layer
of glass is put over the carbon fiber for fairing purposes and to add
resistance to denting from dropping tools or winch handles on the deck.
The breaking strength of these panels were over 34 PSI and more
importantly when fatigue cycled no appreciable softening was found. Also
upon failure of the panel there was a core failure not a skin delamination
as is often common in a honeycomb panel. How did this happen? The lay up
of the deck panels was done out of high tech materials in a fairly low
tech way. The panels were laid up flat on a vacuum table. Compared to some
panels they are relatively resin rich, particularly compared to those
panels that use prepegs. What this extra resin did was to wick it self up
a portion of the honeycomb section and form a “miniscus” that would lock
the core in place to the skin. Also because the panel was laid up flat on
a vacuum table and not wrapped in place the “miniscus” was very even
throughout and not pooled up on one side if laid up on a curved surface.
That is why prepegs are often used is to prevent the pooling of resin in
the honeycomb cell. While the panels might weigh more ( 1 lb. per sq. ft.
versus .8 lbs. per sq. ft. for a prepeg panel) fatigue resistance and
strength comparable to a much heavier balsa core panel was achieved for a
very small incremental gain in weight.
Hull Shape and Stability – When viewing the profile of the hull plan you
will notice that the deepest portion of the hull is forward of the keel
area and that the hull is very deep below the waterline for its
displacement. Because of the deep section forward the run aft is very
long. When viewed in section you will see a very narrow waterline beam
with the hull flaring to provide reserve buoyancy. The front portion of
the boat has a very narrow and deep “V” section almost to the keel. This
is why the boat pounds much less than other ultralight boats. Again this
is counter to the present thinking that light boats had to have “U” shaped
or canoe shaped sections in order to have any stability. This is where the
investment in the carbon fiber and nomex pays off. The stability of the
boat is achieved through a low center of gravity not the hull sections. A
boat with “V” sections would roll excessively if it used balsa or foam
core decks. By keeping the deck weight and the bulkhead weight in the 1
lb. per sq. ft. range the center of gravity is lowered radically compared
to what are considered the high tech production boats on the market. The
deep “V” section also provides compounding benefits on weight distribution
and interior accommodations. By having the round deep sections in the
hull, the integral tanks all are below the water line. This puts the top
of the fuel and water tanks almost a foot below the water line. A full
load of fuel and water of approximately 2000 lbs. now adds to stability.
In most ultralights the fuel and water tanks wind up in the settee area
above the waterline because of the “U” shaped sections or even worse yet
in the ends of the boat. In the RT55 the salon sections in the center of
the boat are now available for extensive provisioning and the load is
averaged right at the waterline. Adding fuel, water and provisions will
actually increase stability like on a heavy displacement boat not decrease
it like on most ultralights. The only reason a heavy displacement boat
increases stability when it is loaded is because the bilges are so far
below the waterline. However anyone who has had to go “locker diving” on
their bellies into the bottom of a locker on a Swan to get a beer will
appreciate the interior storage arrangements in the RT55. Even better yet
all of the provisions, fuel and water are kept in the center of the boat
which will greatly decrease the pitching moment. By being able to use the
fuel and water tanks as the cabin sole the occupants are raised and can
look out the windows in a light and airy interior. The benefits of the
deep “V” sections allowed the designer to draw a hull shape that is almost
even through out its range of heel. Most ultralights will go bow down
because of the broad sterns and “U” shaped sections. The deep “V” section
also greatly lowers the wetted surface and wave making resistance. The
deep narrow section up front greatly disperses the pressure of the bow
wave. The validity of this concept has been proven in the International 14
fleet and also in the America’s Cup where the winning New Zealand boat had
very fine deep sections forward. Also the positive range of stability at
137 degrees again is unprecedented on a boat whose D/L is under 70,
another benefit of the deep “V” sections forward. By using modern
materials to radically lower the center of gravity we now have an
ultralight yacht with load carrying ability and sea keeping characteristic
of a much heavier yacht.

The Rig – Again nonconventional thinking was applied to make the rig easy
to handle, and to supply a great deal of power. The rig is a carbon fiber model manufactured by Hall spars in 2006.  The swept back spreaders allow for a very stable platform
and a mix of rod and Kevlar rigging keep the weight aloft low while still maintaining reliability.  The large roached mainsail provides a great deal of sail area for the
fractional rig with a height of only 65′ 5″ off of the water line. The
bowsprit allows an asymmetrical of over 2200 sq. ft. to be flown and the
RT55 to carry a downwind sail area in excess of 3000 sq. ft. The purpose
of the rig was to keep the weight as low as possible and to keep the
center of effort of the sails as low as possible.
The sail with its large roach also has a
small gaff at the head.  This provides
an “Automatic Transmission” effect. The flexing off of the head also
instantly lowers the center of effort of the sail.
When looking at the mast you will see that it is mounted on a tabernacle
on the cabin top and that the boom is mounted on the tabernacle not
directly on the mast. This prevents the boom loads from being transmitted
to the mast and pushing it forward and destroying the column loading on
the lower section of the mast. Take a look at most carbon mast breaks and
if there is no fitting failure the great majority of the breaks occur at
the lower spreaders. This is because in a puff the mast head rigs pull the
top forward at the Masthead and the boom is pushed forward at the bottom
and the mast is put into an “S” with the hard point being at the lower
spreaders. With the tabernacle absorbing the boom loading and the prebend it is almost impossible for this condition to occur.
Also mounting the boom approximately two feet in back of the mast and
having it pivot there has two additional benefits. The first is that it
allows the boom to swing farther out before hitting the spreaders. The
second is that when the boom does swing out it automatically adds draft to
the sail since the pivot point itself is now asymmetrical because the
radius of the swing is no longer at the mast but in back of the mast.
Unlike most rigs where the mast is straightened going downwind and the out
haul is loosened the RT55 maintains the prebend and adds draft by the
asymmetrical swing of the boom. The conventional rig raises the center of
effort going downwind, the RT55 keeps its center of effort low and the
deep draft and large amount of prebend keeps the air in the sail providing
lift instead of letting it escape around the front creating those wild
gyrating rolls like a conventional rig.
The problem with a rig with no backstay is that it is almost impossible to
get enough head stay tension. In the RT55 this problem is addressed by running backstays which will create enough headstay tension while going upwind, though the rig does not depend on the runners to stay up.  The
carbon in the hull structure combined with the prebend of the mast allows
the head stay tension to be at least as tight as in a conventional rig.
The head sail is very small at only 610 sq. ft. and is mounted on a roller
furler. Tacking is very easy and the boat is so easily driven that you can
still make good speed in light winds but can also keep the working sail
area up in a wide range of wind conditions when combined with the water
ballast. In essence the first reef is adding water ballast.

Water Ballast – In order to maximize going upwind and power reaching the
RT55 uses water ballast. The amount of water ballast is moderate at 1600
lbs. and reduces the angle of heel by about five degrees. The water
ballast is mounted in the aft flared section of the hull in the aft cabins
where it will exert the most leverage. Most ultralights are not known for
their windward abilities, the water ballast allows the RT55 to power up
and develop driving force similar to a much heavier displacement yacht. As
an example, when returning to Seattle from Hawaii there is an approximate
three day beat to the north that starts the trip. In the RT55 you bring
the angle of heel down under a reefed main and jib to a comfortable 15
degrees but the water ballast combined with the low center of gravity,
deep “V” sections and centralized weight displacement will develop the
power you need to make miles to windward in trade wind conditions. This is
where the last generation of ultralight cruisers become almost
uninhabitable, even when motoring to windward. By being able to use water
ballast to power the boat up on a reach and keep the boom from dragging
the potential of breaking the 300 mile per day barrier for a cruiser is
now possible in trade wind conditions.
The water ballast system is a fully automatic system that is push button
activated in the cockpit by the winch islands and is managed by a
Programmable Logic Controller (PLC). The system is designed to either have
the tanks full or empty. If a tank is desired to be full the system will
automatically fill the tank desired and shut off when full. If a tank is
to be evacuated overboard or transferred to the opposite side a push of
the button starts the cycle and will stop it automatically. There is a
flow sensor wired into the PLC to protect the pump and electronically
actuated ball valves control the water flow. All the equipment is
industrial grade and the ball valves are NEMA IV rated. The ball valves
have a manual back up and in the event of a total power failure the tanks
can be evacuated by the manual bilge pump.

Underwater Foils – The underwater foils were optimized to provide lift and
reduce drag. Drag is a particular concern as your speeds begin to climb
because drag increases by the square of the speed. The low wetted surface
will be a benefit here but a big culprit to maintaining top end speed is
the drag of the keel. The other purpose of the keel is to provide lift.
Broad sterned boats when they are heeled have a “virtual” hull shape
driving the boat off to leeward. In low speed conditions these boats need
to be powered up by sailing at almost reaching angles. Some of the more
extreme boats are not able to produce enough lift in low wind conditions
and are sometimes at the back of the pack in these conditions. This is why
it was decided to use a trim tab. The trim tab allows the keel to be only
39 inches wide, including the tab, and by greatly reducing the surface
area the upper end downwind speed is increased and the low speed windward
performance is enhanced. Even more important for a cruising boat when
going to windward in sloppy and steep seas it is possible to point the
boat a little lower and power up the sails and then crank in two to three
degrees of tab angle and still maintain a high VMG to windward.
The foil section of the keel is a moderate laminar flow Eppler Section.
This section has nearly the same lift characteristics as the standard NACA
foil sections that are now common in turbulent or non laminar conditions
and in a laminar flow condition the drag is much less than with a NACA
foil section. The trim tab can induce the laminar condition at very low
speeds by getting the foil to “suck” very quickly.
To add to stability and maintain a low center of gravity a bulb was placed
on the bottom of the keel. The bulb is approximately 6500 lbs. and is all
lead. The keel strut weighs approximately 1400 lbs. and also has an
additional 700 lbs. lead poured into the bottom of the keel. The total
weight of the keel is 8600 lbs. The keel strut is welded out of mild steel
and is galvanized and then coated in epoxy. The keel is mounted in an
aluminum Crash Box that is bolted into a carbon fiber grid. The keel Crash
Box protrudes approximately 18 ” into the boat and the aluminum structure
takes the side loads. The keel is held in place by three pins and is
designed to pivot like a centerboard in the case of a grounding in order
to absorb the loading. The aft lower pin is the pivot pin, the upper front
pin is the “Fuse” pin and is designed to deform or break in a catastrophic
grounding that exceeds 12 knots and allows the keel to pivot and the lower
pin is bushed in a UHMW race that absorbs and controls the aft rotation of
the keel strut. In this condition the keel has pivoted approximately 20
degrees but the boat can be sailed or motored in this condition and is
structurally sound. The pins can be removed and the keel rebushed and
reinstalled. Also this set up will allow for a modular keel such that a
person could easily fit the boat with a keel strut to allow for a 6 foot
draft. Also a person who wanted to motor the canals of Europe could easily
remove the bulb and strut and carry the strut in the dinghy garage or ship
it to a yard on the Med or Baltic bolt the bulb back in place on a very
short dummy strut and have a very safe boat to motor with less than three
feet of draft.
The RT55 has dual rudders for increased control. These rudders are
specially designed foils in their own right. The foils are mildly
asymmetric and are designed to gently push in towards the center when
going straight. This centerline lift adds directional stability similar to
the feathers on an arrow. When the boat begins heeling and the speed is
increasing, the leeward rudder is immersed in the boat’s pressure wave on
the stern and the windward counteracting lift characteristics are reduced.
The lift of the leeward rudder is also increased by the square of the
speed and as a result whether helm is now induced by speed as opposed to
rudder angle. By not having to crank in a lot of rudder angle drag is
greatly reduced and the boat balances similar to a full keel boat. It is
possible in even robust conditions to set the sails and leave the helm for
extended periods of time before steering corrections are made. Also most
rudders have a very narrow drag bucket. This is why those helmsman who are
truly talented can excel because they are able to control the direction of
the boat by keeping their rudder corrections inside the angles of the
rudder’s drag bucket. Those of us less talented make our steering
corrections outside of the drag bucket and will slow our boat down. By
having mildy asymmetric dual rudders the drag bucket is effectively
doubled so those of us that are less talented helmsman now have a much
larger drag bucket in which to make our steering corrections. The rudders
tubes are autoclaved sections with a wall section of .875 inches (22mm)
mounted in heavily reinforced tubes with dual sealed bearings.
Deck Plan – The deck plan and sail controls were designed to accommodate
shorthanded cruising. There is a winch island aft of each helm station.
This configuration allows the helmsman to effectively tack and jibe the
boat with the sail controls close by. No more having to run around the
front of the wheel to trim the mainsail and jib. By having a separate
helmsman area aft it allowed the cockpit to accommodate high secure sides
unencumbered by winches and sail controls. The off watch crew or guest in
the cockpit are no longer in the way when the boat is being sailed. The
cockpit seats are six and a half feet long so that a second crew member
can be sleeping in the cockpit while the helmsman keeps an active watch.
This feature can be appreciated on long passages with a short handed crew.
The walkways on the side decks are secure and wide open. The sails are
raised and lowered at the mast. The only way one person can truly lower,
raise and reef the sails is with the winches the halyards at the mast. In
order to lower sail with the halyards at the cockpit two people are
required. By placing the winches on the tabernacle above the deck they are
conveniently placed for winching up the main and asymmetrical sails. The
boat is also designed to be reefed at the mast. It was felt that a simple
slab reefing system operated at the mast was far more reliable than a
single line reefing with their double internal blocks that have a much
higher probability of jamming and greater internal operating loads. When
you want to put in the third reef the wind is approaching extreme
conditions and the last thing that is needed is to be fussing with your
reefing mechanism. You want the sail secured quickly and easily and to get
back into the cockpit.
There is an arch over the aft end of the cockpit. Electronics such as the
radar and antennas can be mounted on this arch but the real purpose of the
arch is to serve as the hard point for a dodger. Special coamings are
incorporated into the deck forward of the hatch to accept this dodger.
When fully deployed the dodger would enclose the entire cockpit. In the
tropics this dodger would act as a bimini and when motoring up the inside
passage to Alaska on a drizzly day the covered cockpit effectively extends
your interior space.
In the forward section of the boat is a sail and storage locker. The
asymmetrical spinnaker has a bin in this locker so that it can be raised
and lowered directly out of the locker. One person can easily douse the
asymmetrical by collapsing it with the sock and then loosen the halyard
and stand in the sail bin and pull the sail directly into the bin as you
ease the halyard. The asymmetrical spinnaker can produce motoring speeds
in as little as eights knots of true wind. Being able to use this sail
effectively can make passages through the equatorial areas and the Pacific
High much more pleasant and fast.
Forward of the sail locker is the anchor locker. The primary anchor is a
66lb. Bruce on a 100 feet of 5/16 inch high test chain which is attached
to 300 feet of 5/8 inch nylon rode. This anchor is a massive anchor for a
boat this weight and is often used on boats weighing three times as much
as the RT55. The anchor locker has a Lewmar Concept II anchor windlass
controlled by a hand held control. The Lewmar Anchor Windlass has a
special rope chain gypsy so that when raising or lowering the anchor there
isn’t any reason to fuss with switching between the rope and chain
gypsies. The anchor locker is tall, narrow and deep so that the chain and
rode will feed easily. Also the anchor locker is totally self contained
with its own overboard drains so that there is no water intrusion to any
other areas of the boat during heavy weather. The anchor is securely held
in place by a special custom fitting that fits into the bow prodder.
In order to accommodate one of the more difficult problems of storing a
useable dinghy, a dinghy garage is provided in the stern of the boat. This
area will provide for a 12 foot special designed hard dinghy or else a
Rigid Bottom Inflatable with the tubes can be deflated and stored in this
area. At the end of your long passage you can now have easy access to a
useable dinghy.
Engine – The Riptide 55 is powered by a 70 hp Isuzu 4JB1. This engine is a
non turbocharged engine and is a common industrial engine used all over
the world. In generator service this engine is rated at 20,000 hours
between rebuilds. The injector pump and the injectors can be disassembled
and reassembled without any special tools, a real benefit in any third
world country. At 2000 rpm in flat water this engine produces motoring
speeds of approximately 8.5 knots with a two bladed max prop with fuel
consumption being a little over a gallon and a half per hour. At 1800 rpm
fuel consumption decreases such that the range is almost a thousand miles
with the 133 gallons of fuel. Top speed is well over 11 knots at 3000 rpm.
The engine is located close to the center area of the boat and the galley
sink is over the engine compartment. The engine is well ventilated from
the deck and has a large exhuast fan. The engine compartment is
modularized such that the galley sink is removed from the top easily and
all the panels can come off. In less than half an hour the engine is fully
exposed and could be removed. For routine maintenance there are access
panels on all four sides. Oil can be changed, valves adjusted and belts
tightened with ease. The engine compartment is heavily insulated for noise
control.
Interior Accommodations – The RT55 was designed to be comfortable at sea
as well as port. The combination of the forward owner’s cabin and aft
state rooms gives a good combination of port and sea berths. The forward
owner’s cabin is spacious with a full size centerline double bed (no
having to crawl over your partner when getting in and out of bed).
Excellent ventilation is provided by the overhead hatches and overhead
vent. Aft is two cabins each with double berths and there own sinks and
vanity. At sea the aft cabins provide comfortable and secure berths for
the off watch crew.
The RT55 features one generous sized head with a separate shower stall and
centerline head for ease of use no matter what the conditions are. The
feeling of openness and airiness is increased by the added ceiling height
of the mast tabernacle. Enclosed in the mast tabernacle is a vent fan and
hatches that can remain open on the leeward side to provide ventilation.
Opposite of the head are lockers for additional storage and spares. Aft of
the head is a salon which serves as a generous gathering place. Across
from the salon table is a settee which serves as a nice reading area or
sea berth with a lee cloth. Aft of the salon is the galley and nav station
areas. The galley is “U” shaped in order to be secure in all conditions
and the sink is almost on the centerline. There is a 5.7 cubic foot
refrigerator and separate 4.5 cubic foot freezer. These boxes are cooled
by evaperator plates that are driven by a high efficiency hermetically
sealed 110 volt unit. Also in the galley is a microwave and three burner
Force Ten stove. There is extensive storage and locker space. Over the
sink is a special dish drying cabinet to store your dishes at sea or in
port. This locker is designed to place your wet dishes in directly from
the rinse and to allow them to air dry so that they are ready for the next
meal. Across from the galley is a pantry area for the storage of food and
staples.
Next to the pantry is the nav station. This area is designed to be large
enough to serve as the ship’s office and communication center. The nav
station table is large enough so that a full size chart can be studied and
the vertical area adjacent to the nav table is designed to take a full
complement of communication and navigation instrumentation. In between the
nav station and pantry is the electrical panel which is divided into three
DC load groups and a separate AC panel.
The interior walls have a light colored architectural finish to give light
and style to the interior. The galley, salon and nav station area feature
mahogany skinned veneers over nomex cores for a lightweight and dramatic
interior finish. The head area and other cabinets are Awlgriped for
durability. The overhead liner is a leather look vinyl for durability and
is trimmed in mahogany. The counter tops are of high pressure laminates
for style and durability. The cabin sole is painted in Awlgrip and is
light textured for nonskid footing and is extremely durable and easy to
maintain.
Systems – Electrical and plumbing systems are designed to provide long
term cruising capability. The RT55 carries 133 gallons of fuel (503
litres). 120 gallons (454 litres) in integral tanks and 13 gallons (50
litres) in a day tank. The integral tanks have clean outs in the tops. The
use of a day tank minimizes problems with dirty fuel and algae growth.
There is a fuel transfer pump which can be operated from the cockpit. The
fuel is filtered with a 30 micron Racor filter as it is pumped into the
day tank. Between the day tank and the engine is a 10 micron Racor filter
where at the engine the fuel is filtered to the manufacture’s
specification by the engine filter.
The electrical system consist of three battery banks and two alternators
to charge the system. The house bank has three 8D gell cells in parallel
for a 660 amp capacity. There is additional storage space for a fourth 8D
gell cell if desired. The house bank has its own dedicated 200 amp Balmar
high capacity alternator. There is a Group 27 engine starting battery and
a Group 27 electronics buffer battery. The engine battery and electronics
battery are charged by a 35 amp alternator. A 2500 watt Heart Inverter
will supply 110 volt power when not at the dock. The inverter has a 130
amp 12 volt charger built into it.
The water ballast system is driven by a 1/2 hp (.4 kw.) 12 volt motor.
There are six 110 volt electronically operated ball valves to control the
water distribution. The whole system is controlled by a Koyo Programmable
Logic Controller (PLC). Protecting the pump is a flow sensor. In the event
of a valve failure the valves can be operated by hand and in the event of
a total power failure the system can be evacuated by the manual bilge
pump. In an emergency situation the pump can be disconnected from the
(PLC) and can serve as a very high capacity bilge pump. The system is push
buttoned operated at panels located in the cockpit.
The head is a Lavac unit and is electrically activated. The Lavac unit was
chosen for its reputation for reliability. The head is operated by vacuum
and there is no moving parts. The pump is a large bilge pump and is
extremely rugged and has a clean out provided. Directly in back of the
head is a panel that controls if the sewage is pumped overboard or into
the 54 gallon (204 liters) integral sewage tank. The pump on the Lavac
unit also serves to pump out the sewage tank overboard and is operated by
the control panel in back of the head. There is a dock side pump out
provided.
The fresh water system carries 90 gallons (340 litres) in two 45 gallon
(170 litre) integral tanks built into the cabin sole, 20 gallons (75
litres) in an aft tank and 11 gallons (41 litres) in the water heater for
a total of 121 gallons. It is anticipated that the aft water tank will
serve as the tank to receive the output from a water maker. There is a
water distribution manifold on the intake side of the pressure system to
control which tank is being used. In addition to the pressure system are
four manual pumps. These pumps are located in the galley, the aft cabins
and the head. These pumps will serve as backups in the event of a
pressure failure but also can be used to conserve water usage by turning
of the pressure system.
The salt water system is an on demand pressure system with three taps. One
in the anchor locker for anchor and deck washdown, one in the stern for
deck wash down and one in the galley.
Dimensions
Length overall: 56.0
Length fairbody: 54.5
Length waterline: 53.0
Maximum beam: 14.7
Draft:  9.6
Displacement: 21,000
Ballast: 9280
Water ballast:1600 lbs per side
Sail area: working = 1480, maximum offwind = 3094
I:  60.5 J:26  P:57.6  E:20.5
Hull color: Blue
Engine
70 hp Isuzu
4JB1 Transmission
Hearth HBW 250
Fwd. Reduction Ratio – 2.01/1.00
Shaft – 1 3/8″ Aquamet 22
Strut – Cast Bronze
Propeller-Max-prop
Accommodations
3 stateroom, one forward, 2 aft
One head, lavac electric
Separate stall shower
Heating system: 30000 BTU Webasto DBW90 with four radiator fans
Hotwater – ll gallon Torrid with Stainless Steel Jacket. Tank is heated
by either shore power or Webasto Heater.
Galley
5.7 cubic foot box in galley for refrigerated items cooled by an
evaporator plate
4.5 cubic foot freezer box in galley cooled by an evaporator plate
All boxes have at least four inches of foam insulation surrounding them
Compressor is a Glacier bay system, water cooled.
Force 10 three burner stove with oven and broiler in Galley fueled by
propane.
Four 10lb. aluminium propane bottles with regulator and solenoid in
helmsman seat lockers

Tankage
Fuel:  133 total gallons, in two 60 gallon integral tanks and a 13
gallon stainless steel day tank
Water: 120 total gallons, in two 45 gallon integral tanks and one 20
gallon tanks
Holding: grey water, 20 gallons
Holding: black water, 54 gallons, integral
Electronic and navigation equipment
WS Sensor – B&G
Speed Sensor – B&G
Depth Sensor – B&G
Fluxgate Compass –B&G
Cockpit Displays – B&G
Four Dual Displays in Cockpit
Radar – Simrad
GPS – Garmin 120
VHF – Icom
AIS-Vesper marine
Electrical system
Shore power: 110v
House Bank – Three 8D Prevailer Gel Cells
Engine Starting Battery – Group 27 Prevailer Gel Cell
Electronics Buffer Battery – Group 27 Prevailer Gel Cell
Alternators and Charging
Main Alternator – Balmar 200 Amp directly charging the house bank
Secondary Alternator – 35 Amp charges the engine starting battery and
electronics buffer battery.
The secondary alternator can charge all banks and the engine can be
started and the electronics can run just from the house bank.
Shoreside charging is done by the 2500 watt Heart Inverter which has a
built in three step multi level 130 amp charger.
120 AC system
Shore Power is supplied by a 30 amp supply
110 AC can be supplied by either the 30 amp shore power supply or the
2500 Watt Heart Inverter.
The Inverter drives both the 110 refrigeration and the electronically
actuated ball valves.
The Inverter is managed by the Link 2000 mounted directly in the panel
and charging is supplied by the inverter.
Distribution
Distribution is by two custom panels by M and I Electronics. One panel
is for the 12 volt DC distribution and one panel is for AC distribution.

Deck equipment
6 – 8″ Schaffer Aluminium Cleats
30″ High Schaffer lifeline stanchions with boarding gates
Custom made bow and stern pulpits
Swim Step off of Dinghy Garage
4 – Lewmar Coastline 040
4 – Lewmar Coastline 010
6 – Lewmar Coastline 020
2- Lewmar Atlantic 010
1- Custom Sail Locker hatch by Lewmar with Kevlar and Nomex cover
instead of acylic for weight savings
All hatches except for the sail locker hatch have special order white
frames with custom rose bronze acrylic windows.
Sails and rigging
Sails
Main: 880 square foot Fusion by Quantum. Carbon fiber/Technora/Mylar laminate. Mast Track System is by Antal with Batten attachments by Sail
Power Systems. Mainsail has three sets of reef points.
Jibs: Working Jib is 600 square foot fusion by Quantum, with foam padded luff for
furling.
3 spinnakers of various sizes and weights
1 Code Zero mylar laminate on furler
1 Storm Jib
1 Storm Staysail
1 Storm trysail
Winches
Jib Sheet – Harken 56STA
(2) Main Sheet – Harken 53STA
Main Traveler – Harken 45STA
Halyard – Harken 45STA Electric
Spars and rigging
Spar – Carbon Fiber Spar by Hall spars, dual spreader with running backstays. Six Lewmar Halyard Clutches
on mast. Lazy Jacks with internal mast feed act as topping lift and
assist in furling.
Standing Rigging – All standing rigging is rod rigging by Navtec with the exception of the removable inner forestay, which is Kevlar
Runners – Running Backstays are Kevlar by Navtec.
Boom – Carbon fiber boom with foam core reinforced with plywood in high
stress areas.
Running Rigging – All Running is by Samson as noted below:
Main Halyard – 7/16″ UltraTech
Jib Halyard – 3/8″ UltraTech
Spin Halyard – 5/16″ Spectron dacron cover
Genoa Halyard – 5/16″ Spectron dacron cover
Mainsheet Sheet – 1/2″ XLS
Main Traveler – 7/16″ XLS
Running Backstays – 1/2″ UltraTech
Jib Sheets- – 9/16″ XLS
Spinnaker Sheets – 1/2″ XLS
Pole – Carbon fiber bow launched asymmetrical spinnaker pole. Pole is
extended by single line pull.
Water ballast
Port and Starboard Ballast Tanks of 200 gallons each
Electronically activated by instantaneous push buttons in cockpit arch
mounted in custom panels by M and I electronics.
1/2 hp. 12 volt Leeson motor driving a centrifugal pump rated at 60 GPM.

6 electronically actuated ball valves by Harrington
Effector Flow sensor on pump intake controls fill, empty, transfer
cycles and protects pump.
Koyo Programmable Logic Controller controls and coordinates the
automatic operation of the system.
Steering
Dual rudders. Rudders are asymmetrical to provide mild lift.
Rudders are by Advanced Composites and have 3.5″ outside diameter shaft
with an autoclaved carbon wall thickness of .875″.
Steering system has dual outboard pedestals and is a rod linked cobra
system by Whitlock with rack and pinion inputs in the pedestal heads.
There are two 36″ destroyer type wheels.
Each pedestal has a Ritchie Compass mounted in the pedestal.

Awesome, this plus Julian B's description of his thinking re: his 89er are excellent education about how to think fast and strong.   But,  help me with the SA/D above, I'm getting wonky low numbers for U and D wind.  The SA is square feet right, and weight in lbs?

 

[floater]

From here: http://svrocketscience.com/technical-details/

Model: Riptide 55 Designer: Paul Bieker. Built at Shaw boats in Aberdeen, WA. Finishing and commissioning were done at Seaview West and CSR in Seattle.

Construction: Carbon fiber/glass/duracore balsa /nomex composite

Design Objectives – The RipTide 55 is designed to be the next generation
of club racing and long distance cruising yacht. Rather than a highly
specialized cruising yacht like the Sun Deer or Deer Foot series, the
emphasis is on an all around boat that can be used for club racing and
coastal cruising but is also engineered and capable of long ocean
passages. This is the same concept that Nautor and Baltic have used for
years that has preserved the value of their boats over a sustained period
of time. However unlike Nautor and Baltic who have not updated their use
of materials or available technologies, the Riptide 55 incorporates very high-tech
materials and proven design concepts that have proved themselves
over the years at the highest level of offshore ocean racing.
Extensive use of carbon fiber, kevlar and honeycomb cores has produced a boat with ultralight
displacement ratios and with the strength and integrity that is far in
excess of even the stoutest cruising boats. From the comments below you
will see how using these materials to lower the center of gravity has
produced a very light boat that has an extremely seakindly motion and very
little tendency to pound. Pounding when going to windward has been the
Achilles heel of the last generation of light weight cruising boats. Some
manufactures have even tried to side step this problem by installing large
engines and focus on the virtues of motoring to windward.

Design and Engineering Process – The RipTide 55 used a paperless design
and engineering process. The design, drawing and engineering process was
integrated into one process and was all done on the computer. It is not
uncommon in today’s design world to have one person draw the lines by hand
then turn their work over to another person who then adds the interior,
another person then takes those drawings and inputs them into the computer
after all this is done the plans are then turned over to a structural
engineer who often takes a “cookbook” approach to figuring out panel,
stringer and laminate scantlings. The designer, Paul Bieker, did all the
CAD work, finite element analysis and engineering. Paul is known for his
engineering expertise in structural trouble shooting on large ships and
yachts. Paul is also known for producing this country’s fastest
International 14 Designs and Paul has logged over 50,000 offshore miles
cruising. Paul is one of the few designers that has the ability to
integrate the engineering and design process all in a paperless computer
design that truly has everything meeting in three dimensions. This process
is often used on the large commercial ships but is rarely seen in the
world of yacht design. In addition Paul is on the leading edge of monohull
development by his dedication to the International 14 class which has
pioneered most of today’s speed innovations such as articulating
bowsprits, flexible rigs, and large roached mainsails. Paul also is part of the design team for the BMW/Oracle team, with the latest example of his work being the design of the lifting foils for the AC72 catamaran being used in the America’s cup defense.  Paul’s intuitive
design insights and fundamental understanding of today’s modern materials
has produced a truly unique yacht which is not available anywhere else and
the concepts of which could not be easily reproduced without the subtle
knowledge of how these materials were used.

Structural Integrity – In order to be a truly seaworthy yacht the Riptide
55 had to be able to endure years of ocean abuse and be able to sustain
hull integrity in the case of hitting a log or container at 14 knots or
hitting a rock with the keel at 12 plus knots. In order to accomplish
these requirements true base line engineering was used that combined
finite element analysis along with a panel testing program that field
tested the computer assumptions.
What was apparent from the polar predictions was the extreme speeds that a
yacht like the Riptide 55 can generate. For this reason it was decided not
to use the ABS guidelines for yachts, those standards did not adequately
address the speed potential of today’s modern craft. Instead the standards
selected were ABS slamming standards for high speed military craft and Det
Norske Veritas standards for high speed offshore motor craft. Using these
standards a loading of 7.5 PSI was arrived at, approximately double ABS
standards. To put this number into perspective, the RT55 could slam on an
area of a little over a square meter in front of the keel for the life of
the boat. These are extreme conditions found when flying off of waves in
the worst conditions. In order to keep the panel from flexing and to
provide fatigue resistance the panel specification was set at 40 PSI so
that the maximum loading was not to exceed 20% of the panels specified
breaking strength. A laminate schedule was modeled in the computer and
then panels were made by the builder and tested by Gugeon Brothers to see
if they met the specifications. The panel for the hull bottom has a core
of 1″ Baltec Duracore and skins of carbon fiber and unidirectional glass.
Upon testing of these panels a breaking strength of 54 PSI was found, well
in excess of the 40 PSI specification and a number realized only in high
speed power craft. Even more important in a panel test of 400,000 flexing
cycles of 25 PSI ( half the panels breaking strength and over three times
the required extreme specification) no softening was found. This is
unprecedented. The next time a manufacturer makes claims about their
hull’s strength ask to see the documentation for the underlying
engineering assumptions, the finite element analysis and the panel testing
data to back up the assumptions in the finite element analysis.
The question becomes why make the panel so strong. The answer is that the
panel had not only to sustain the slamming conditions at sea but with all
the debris in the modern ocean it had to be able to sustain a collision
with a solid object such as a log or a cargo container that had been lost
off of a deck of a ship. Keep in mind that the RT55 is capable of speeds
over 20 knots. The deceleration from such a hit would be dangerous enough
without having to worry if the boat would disintegrate. As further
protection from such a catastrophic situation a kevlar crash barrier
laminate was added in the center 30 inches of the hull forward of the
keel. This laminate is next to the core on both sides underneath the
carbon fiber. This is counter to present conventional thinking which would
put the kevlar on the outer laminate because of its abrasion resistance.
What was found in the panel testing at Guegon was that the kevlar in a
catasrophic hit would shatter on the outside skin because of its
brittleness and the stiffness of the underlying core and laminates and
even potentially holed. Dropping heavy metal balls on the laminate it was
found that while the glass and carbon skins were breached that the
laminate hung together because the kevlar as the last line of defense
works in tension to absorb the energy of the of the object and while
delamination occurred the laminate was not breached. As a belt and
suspenders approach to hull integrity, integral sewage, fuel and water
tanks form a double bottom in the critical areas of the boat in case of a
grounding on a beach or a reef. The RT55 also has forward and aft semi
water tight compartments to increase survivability in the case of a
collision.
While there was much attention to the hull and its integrity, the decks
had many requirements put on them. They had to sustain heavy seas and
provide a stiff lid to the whole boat. The deck panels on the RT55 are
carbon fiber skins over a honeycomb HRT type core and then a 4 oz. layer
of glass is put over the carbon fiber for fairing purposes and to add
resistance to denting from dropping tools or winch handles on the deck.
The breaking strength of these panels were over 34 PSI and more
importantly when fatigue cycled no appreciable softening was found. Also
upon failure of the panel there was a core failure not a skin delamination
as is often common in a honeycomb panel. How did this happen? The lay up
of the deck panels was done out of high tech materials in a fairly low
tech way. The panels were laid up flat on a vacuum table. Compared to some
panels they are relatively resin rich, particularly compared to those
panels that use prepegs. What this extra resin did was to wick it self up
a portion of the honeycomb section and form a “miniscus” that would lock
the core in place to the skin. Also because the panel was laid up flat on
a vacuum table and not wrapped in place the “miniscus” was very even
throughout and not pooled up on one side if laid up on a curved surface.
That is why prepegs are often used is to prevent the pooling of resin in
the honeycomb cell. While the panels might weigh more ( 1 lb. per sq. ft.
versus .8 lbs. per sq. ft. for a prepeg panel) fatigue resistance and
strength comparable to a much heavier balsa core panel was achieved for a
very small incremental gain in weight.
Hull Shape and Stability – When viewing the profile of the hull plan you
will notice that the deepest portion of the hull is forward of the keel
area and that the hull is very deep below the waterline for its
displacement. Because of the deep section forward the run aft is very
long. When viewed in section you will see a very narrow waterline beam
with the hull flaring to provide reserve buoyancy. The front portion of
the boat has a very narrow and deep “V” section almost to the keel. This
is why the boat pounds much less than other ultralight boats. Again this
is counter to the present thinking that light boats had to have “U” shaped
or canoe shaped sections in order to have any stability. This is where the
investment in the carbon fiber and nomex pays off. The stability of the
boat is achieved through a low center of gravity not the hull sections. A
boat with “V” sections would roll excessively if it used balsa or foam
core decks. By keeping the deck weight and the bulkhead weight in the 1
lb. per sq. ft. range the center of gravity is lowered radically compared
to what are considered the high tech production boats on the market. The
deep “V” section also provides compounding benefits on weight distribution
and interior accommodations. By having the round deep sections in the
hull, the integral tanks all are below the water line. This puts the top
of the fuel and water tanks almost a foot below the water line. A full
load of fuel and water of approximately 2000 lbs. now adds to stability.
In most ultralights the fuel and water tanks wind up in the settee area
above the waterline because of the “U” shaped sections or even worse yet
in the ends of the boat. In the RT55 the salon sections in the center of
the boat are now available for extensive provisioning and the load is
averaged right at the waterline. Adding fuel, water and provisions will
actually increase stability like on a heavy displacement boat not decrease
it like on most ultralights. The only reason a heavy displacement boat
increases stability when it is loaded is because the bilges are so far
below the waterline. However anyone who has had to go “locker diving” on
their bellies into the bottom of a locker on a Swan to get a beer will
appreciate the interior storage arrangements in the RT55. Even better yet
all of the provisions, fuel and water are kept in the center of the boat
which will greatly decrease the pitching moment. By being able to use the
fuel and water tanks as the cabin sole the occupants are raised and can
look out the windows in a light and airy interior. The benefits of the
deep “V” sections allowed the designer to draw a hull shape that is almost
even through out its range of heel. Most ultralights will go bow down
because of the broad sterns and “U” shaped sections. The deep “V” section
also greatly lowers the wetted surface and wave making resistance. The
deep narrow section up front greatly disperses the pressure of the bow
wave. The validity of this concept has been proven in the International 14
fleet and also in the America’s Cup where the winning New Zealand boat had
very fine deep sections forward. Also the positive range of stability at
137 degrees again is unprecedented on a boat whose D/L is under 70,
another benefit of the deep “V” sections forward. By using modern
materials to radically lower the center of gravity we now have an
ultralight yacht with load carrying ability and sea keeping characteristic
of a much heavier yacht.

The Rig – Again nonconventional thinking was applied to make the rig easy
to handle, and to supply a great deal of power. The rig is a carbon fiber model manufactured by Hall spars in 2006.  The swept back spreaders allow for a very stable platform
and a mix of rod and Kevlar rigging keep the weight aloft low while still maintaining reliability.  The large roached mainsail provides a great deal of sail area for the
fractional rig with a height of only 65′ 5″ off of the water line. The
bowsprit allows an asymmetrical of over 2200 sq. ft. to be flown and the
RT55 to carry a downwind sail area in excess of 3000 sq. ft. The purpose
of the rig was to keep the weight as low as possible and to keep the
center of effort of the sails as low as possible.
The sail with its large roach also has a
small gaff at the head.  This provides
an “Automatic Transmission” effect. The flexing off of the head also
instantly lowers the center of effort of the sail.
When looking at the mast you will see that it is mounted on a tabernacle
on the cabin top and that the boom is mounted on the tabernacle not
directly on the mast. This prevents the boom loads from being transmitted
to the mast and pushing it forward and destroying the column loading on
the lower section of the mast. Take a look at most carbon mast breaks and
if there is no fitting failure the great majority of the breaks occur at
the lower spreaders. This is because in a puff the mast head rigs pull the
top forward at the Masthead and the boom is pushed forward at the bottom
and the mast is put into an “S” with the hard point being at the lower
spreaders. With the tabernacle absorbing the boom loading and the prebend it is almost impossible for this condition to occur.
Also mounting the boom approximately two feet in back of the mast and
having it pivot there has two additional benefits. The first is that it
allows the boom to swing farther out before hitting the spreaders. The
second is that when the boom does swing out it automatically adds draft to
the sail since the pivot point itself is now asymmetrical because the
radius of the swing is no longer at the mast but in back of the mast.
Unlike most rigs where the mast is straightened going downwind and the out
haul is loosened the RT55 maintains the prebend and adds draft by the
asymmetrical swing of the boom. The conventional rig raises the center of
effort going downwind, the RT55 keeps its center of effort low and the
deep draft and large amount of prebend keeps the air in the sail providing
lift instead of letting it escape around the front creating those wild
gyrating rolls like a conventional rig.
The problem with a rig with no backstay is that it is almost impossible to
get enough head stay tension. In the RT55 this problem is addressed by running backstays which will create enough headstay tension while going upwind, though the rig does not depend on the runners to stay up.  The
carbon in the hull structure combined with the prebend of the mast allows
the head stay tension to be at least as tight as in a conventional rig.
The head sail is very small at only 610 sq. ft. and is mounted on a roller
furler. Tacking is very easy and the boat is so easily driven that you can
still make good speed in light winds but can also keep the working sail
area up in a wide range of wind conditions when combined with the water
ballast. In essence the first reef is adding water ballast.

Water Ballast – In order to maximize going upwind and power reaching the
RT55 uses water ballast. The amount of water ballast is moderate at 1600
lbs. and reduces the angle of heel by about five degrees. The water
ballast is mounted in the aft flared section of the hull in the aft cabins
where it will exert the most leverage. Most ultralights are not known for
their windward abilities, the water ballast allows the RT55 to power up
and develop driving force similar to a much heavier displacement yacht. As
an example, when returning to Seattle from Hawaii there is an approximate
three day beat to the north that starts the trip. In the RT55 you bring
the angle of heel down under a reefed main and jib to a comfortable 15
degrees but the water ballast combined with the low center of gravity,
deep “V” sections and centralized weight displacement will develop the
power you need to make miles to windward in trade wind conditions. This is
where the last generation of ultralight cruisers become almost
uninhabitable, even when motoring to windward. By being able to use water
ballast to power the boat up on a reach and keep the boom from dragging
the potential of breaking the 300 mile per day barrier for a cruiser is
now possible in trade wind conditions.
The water ballast system is a fully automatic system that is push button
activated in the cockpit by the winch islands and is managed by a
Programmable Logic Controller (PLC). The system is designed to either have
the tanks full or empty. If a tank is desired to be full the system will
automatically fill the tank desired and shut off when full. If a tank is
to be evacuated overboard or transferred to the opposite side a push of
the button starts the cycle and will stop it automatically. There is a
flow sensor wired into the PLC to protect the pump and electronically
actuated ball valves control the water flow. All the equipment is
industrial grade and the ball valves are NEMA IV rated. The ball valves
have a manual back up and in the event of a total power failure the tanks
can be evacuated by the manual bilge pump.

Underwater Foils – The underwater foils were optimized to provide lift and
reduce drag. Drag is a particular concern as your speeds begin to climb
because drag increases by the square of the speed. The low wetted surface
will be a benefit here but a big culprit to maintaining top end speed is
the drag of the keel. The other purpose of the keel is to provide lift.
Broad sterned boats when they are heeled have a “virtual” hull shape
driving the boat off to leeward. In low speed conditions these boats need
to be powered up by sailing at almost reaching angles. Some of the more
extreme boats are not able to produce enough lift in low wind conditions
and are sometimes at the back of the pack in these conditions. This is why
it was decided to use a trim tab. The trim tab allows the keel to be only
39 inches wide, including the tab, and by greatly reducing the surface
area the upper end downwind speed is increased and the low speed windward
performance is enhanced. Even more important for a cruising boat when
going to windward in sloppy and steep seas it is possible to point the
boat a little lower and power up the sails and then crank in two to three
degrees of tab angle and still maintain a high VMG to windward.
The foil section of the keel is a moderate laminar flow Eppler Section.
This section has nearly the same lift characteristics as the standard NACA
foil sections that are now common in turbulent or non laminar conditions
and in a laminar flow condition the drag is much less than with a NACA
foil section. The trim tab can induce the laminar condition at very low
speeds by getting the foil to “suck” very quickly.
To add to stability and maintain a low center of gravity a bulb was placed
on the bottom of the keel. The bulb is approximately 6500 lbs. and is all
lead. The keel strut weighs approximately 1400 lbs. and also has an
additional 700 lbs. lead poured into the bottom of the keel. The total
weight of the keel is 8600 lbs. The keel strut is welded out of mild steel
and is galvanized and then coated in epoxy. The keel is mounted in an
aluminum Crash Box that is bolted into a carbon fiber grid. The keel Crash
Box protrudes approximately 18 ” into the boat and the aluminum structure
takes the side loads. The keel is held in place by three pins and is
designed to pivot like a centerboard in the case of a grounding in order
to absorb the loading. The aft lower pin is the pivot pin, the upper front
pin is the “Fuse” pin and is designed to deform or break in a catastrophic
grounding that exceeds 12 knots and allows the keel to pivot and the lower
pin is bushed in a UHMW race that absorbs and controls the aft rotation of
the keel strut. In this condition the keel has pivoted approximately 20
degrees but the boat can be sailed or motored in this condition and is
structurally sound. The pins can be removed and the keel rebushed and
reinstalled. Also this set up will allow for a modular keel such that a
person could easily fit the boat with a keel strut to allow for a 6 foot
draft. Also a person who wanted to motor the canals of Europe could easily
remove the bulb and strut and carry the strut in the dinghy garage or ship
it to a yard on the Med or Baltic bolt the bulb back in place on a very
short dummy strut and have a very safe boat to motor with less than three
feet of draft.
The RT55 has dual rudders for increased control. These rudders are
specially designed foils in their own right. The foils are mildly
asymmetric and are designed to gently push in towards the center when
going straight. This centerline lift adds directional stability similar to
the feathers on an arrow. When the boat begins heeling and the speed is
increasing, the leeward rudder is immersed in the boat’s pressure wave on
the stern and the windward counteracting lift characteristics are reduced.
The lift of the leeward rudder is also increased by the square of the
speed and as a result whether helm is now induced by speed as opposed to
rudder angle. By not having to crank in a lot of rudder angle drag is
greatly reduced and the boat balances similar to a full keel boat. It is
possible in even robust conditions to set the sails and leave the helm for
extended periods of time before steering corrections are made. Also most
rudders have a very narrow drag bucket. This is why those helmsman who are
truly talented can excel because they are able to control the direction of
the boat by keeping their rudder corrections inside the angles of the
rudder’s drag bucket. Those of us less talented make our steering
corrections outside of the drag bucket and will slow our boat down. By
having mildy asymmetric dual rudders the drag bucket is effectively
doubled so those of us that are less talented helmsman now have a much
larger drag bucket in which to make our steering corrections. The rudders
tubes are autoclaved sections with a wall section of .875 inches (22mm)
mounted in heavily reinforced tubes with dual sealed bearings.
Deck Plan – The deck plan and sail controls were designed to accommodate
shorthanded cruising. There is a winch island aft of each helm station.
This configuration allows the helmsman to effectively tack and jibe the
boat with the sail controls close by. No more having to run around the
front of the wheel to trim the mainsail and jib. By having a separate
helmsman area aft it allowed the cockpit to accommodate high secure sides
unencumbered by winches and sail controls. The off watch crew or guest in
the cockpit are no longer in the way when the boat is being sailed. The
cockpit seats are six and a half feet long so that a second crew member
can be sleeping in the cockpit while the helmsman keeps an active watch.
This feature can be appreciated on long passages with a short handed crew.
The walkways on the side decks are secure and wide open. The sails are
raised and lowered at the mast. The only way one person can truly lower,
raise and reef the sails is with the winches the halyards at the mast. In
order to lower sail with the halyards at the cockpit two people are
required. By placing the winches on the tabernacle above the deck they are
conveniently placed for winching up the main and asymmetrical sails. The
boat is also designed to be reefed at the mast. It was felt that a simple
slab reefing system operated at the mast was far more reliable than a
single line reefing with their double internal blocks that have a much
higher probability of jamming and greater internal operating loads. When
you want to put in the third reef the wind is approaching extreme
conditions and the last thing that is needed is to be fussing with your
reefing mechanism. You want the sail secured quickly and easily and to get
back into the cockpit.
There is an arch over the aft end of the cockpit. Electronics such as the
radar and antennas can be mounted on this arch but the real purpose of the
arch is to serve as the hard point for a dodger. Special coamings are
incorporated into the deck forward of the hatch to accept this dodger.
When fully deployed the dodger would enclose the entire cockpit. In the
tropics this dodger would act as a bimini and when motoring up the inside
passage to Alaska on a drizzly day the covered cockpit effectively extends
your interior space.
In the forward section of the boat is a sail and storage locker. The
asymmetrical spinnaker has a bin in this locker so that it can be raised
and lowered directly out of the locker. One person can easily douse the
asymmetrical by collapsing it with the sock and then loosen the halyard
and stand in the sail bin and pull the sail directly into the bin as you
ease the halyard. The asymmetrical spinnaker can produce motoring speeds
in as little as eights knots of true wind. Being able to use this sail
effectively can make passages through the equatorial areas and the Pacific
High much more pleasant and fast.
Forward of the sail locker is the anchor locker. The primary anchor is a
66lb. Bruce on a 100 feet of 5/16 inch high test chain which is attached
to 300 feet of 5/8 inch nylon rode. This anchor is a massive anchor for a
boat this weight and is often used on boats weighing three times as much
as the RT55. The anchor locker has a Lewmar Concept II anchor windlass
controlled by a hand held control. The Lewmar Anchor Windlass has a
special rope chain gypsy so that when raising or lowering the anchor there
isn’t any reason to fuss with switching between the rope and chain
gypsies. The anchor locker is tall, narrow and deep so that the chain and
rode will feed easily. Also the anchor locker is totally self contained
with its own overboard drains so that there is no water intrusion to any
other areas of the boat during heavy weather. The anchor is securely held
in place by a special custom fitting that fits into the bow prodder.
In order to accommodate one of the more difficult problems of storing a
useable dinghy, a dinghy garage is provided in the stern of the boat. This
area will provide for a 12 foot special designed hard dinghy or else a
Rigid Bottom Inflatable with the tubes can be deflated and stored in this
area. At the end of your long passage you can now have easy access to a
useable dinghy.
Engine – The Riptide 55 is powered by a 70 hp Isuzu 4JB1. This engine is a
non turbocharged engine and is a common industrial engine used all over
the world. In generator service this engine is rated at 20,000 hours
between rebuilds. The injector pump and the injectors can be disassembled
and reassembled without any special tools, a real benefit in any third
world country. At 2000 rpm in flat water this engine produces motoring
speeds of approximately 8.5 knots with a two bladed max prop with fuel
consumption being a little over a gallon and a half per hour. At 1800 rpm
fuel consumption decreases such that the range is almost a thousand miles
with the 133 gallons of fuel. Top speed is well over 11 knots at 3000 rpm.
The engine is located close to the center area of the boat and the galley
sink is over the engine compartment. The engine is well ventilated from
the deck and has a large exhuast fan. The engine compartment is
modularized such that the galley sink is removed from the top easily and
all the panels can come off. In less than half an hour the engine is fully
exposed and could be removed. For routine maintenance there are access
panels on all four sides. Oil can be changed, valves adjusted and belts
tightened with ease. The engine compartment is heavily insulated for noise
control.
Interior Accommodations – The RT55 was designed to be comfortable at sea
as well as port. The combination of the forward owner’s cabin and aft
state rooms gives a good combination of port and sea berths. The forward
owner’s cabin is spacious with a full size centerline double bed (no
having to crawl over your partner when getting in and out of bed).
Excellent ventilation is provided by the overhead hatches and overhead
vent. Aft is two cabins each with double berths and there own sinks and
vanity. At sea the aft cabins provide comfortable and secure berths for
the off watch crew.
The RT55 features one generous sized head with a separate shower stall and
centerline head for ease of use no matter what the conditions are. The
feeling of openness and airiness is increased by the added ceiling height
of the mast tabernacle. Enclosed in the mast tabernacle is a vent fan and
hatches that can remain open on the leeward side to provide ventilation.
Opposite of the head are lockers for additional storage and spares. Aft of
the head is a salon which serves as a generous gathering place. Across
from the salon table is a settee which serves as a nice reading area or
sea berth with a lee cloth. Aft of the salon is the galley and nav station
areas. The galley is “U” shaped in order to be secure in all conditions
and the sink is almost on the centerline. There is a 5.7 cubic foot
refrigerator and separate 4.5 cubic foot freezer. These boxes are cooled
by evaperator plates that are driven by a high efficiency hermetically
sealed 110 volt unit. Also in the galley is a microwave and three burner
Force Ten stove. There is extensive storage and locker space. Over the
sink is a special dish drying cabinet to store your dishes at sea or in
port. This locker is designed to place your wet dishes in directly from
the rinse and to allow them to air dry so that they are ready for the next
meal. Across from the galley is a pantry area for the storage of food and
staples.
Next to the pantry is the nav station. This area is designed to be large
enough to serve as the ship’s office and communication center. The nav
station table is large enough so that a full size chart can be studied and
the vertical area adjacent to the nav table is designed to take a full
complement of communication and navigation instrumentation. In between the
nav station and pantry is the electrical panel which is divided into three
DC load groups and a separate AC panel.
The interior walls have a light colored architectural finish to give light
and style to the interior. The galley, salon and nav station area feature
mahogany skinned veneers over nomex cores for a lightweight and dramatic
interior finish. The head area and other cabinets are Awlgriped for
durability. The overhead liner is a leather look vinyl for durability and
is trimmed in mahogany. The counter tops are of high pressure laminates
for style and durability. The cabin sole is painted in Awlgrip and is
light textured for nonskid footing and is extremely durable and easy to
maintain.
Systems – Electrical and plumbing systems are designed to provide long
term cruising capability. The RT55 carries 133 gallons of fuel (503
litres). 120 gallons (454 litres) in integral tanks and 13 gallons (50
litres) in a day tank. The integral tanks have clean outs in the tops. The
use of a day tank minimizes problems with dirty fuel and algae growth.
There is a fuel transfer pump which can be operated from the cockpit. The
fuel is filtered with a 30 micron Racor filter as it is pumped into the
day tank. Between the day tank and the engine is a 10 micron Racor filter
where at the engine the fuel is filtered to the manufacture’s
specification by the engine filter.
The electrical system consist of three battery banks and two alternators
to charge the system. The house bank has three 8D gell cells in parallel
for a 660 amp capacity. There is additional storage space for a fourth 8D
gell cell if desired. The house bank has its own dedicated 200 amp Balmar
high capacity alternator. There is a Group 27 engine starting battery and
a Group 27 electronics buffer battery. The engine battery and electronics
battery are charged by a 35 amp alternator. A 2500 watt Heart Inverter
will supply 110 volt power when not at the dock. The inverter has a 130
amp 12 volt charger built into it.
The water ballast system is driven by a 1/2 hp (.4 kw.) 12 volt motor.
There are six 110 volt electronically operated ball valves to control the
water distribution. The whole system is controlled by a Koyo Programmable
Logic Controller (PLC). Protecting the pump is a flow sensor. In the event
of a valve failure the valves can be operated by hand and in the event of
a total power failure the system can be evacuated by the manual bilge
pump. In an emergency situation the pump can be disconnected from the
(PLC) and can serve as a very high capacity bilge pump. The system is push
buttoned operated at panels located in the cockpit.
The head is a Lavac unit and is electrically activated. The Lavac unit was
chosen for its reputation for reliability. The head is operated by vacuum
and there is no moving parts. The pump is a large bilge pump and is
extremely rugged and has a clean out provided. Directly in back of the
head is a panel that controls if the sewage is pumped overboard or into
the 54 gallon (204 liters) integral sewage tank. The pump on the Lavac
unit also serves to pump out the sewage tank overboard and is operated by
the control panel in back of the head. There is a dock side pump out
provided.
The fresh water system carries 90 gallons (340 litres) in two 45 gallon
(170 litre) integral tanks built into the cabin sole, 20 gallons (75
litres) in an aft tank and 11 gallons (41 litres) in the water heater for
a total of 121 gallons. It is anticipated that the aft water tank will
serve as the tank to receive the output from a water maker. There is a
water distribution manifold on the intake side of the pressure system to
control which tank is being used. In addition to the pressure system are
four manual pumps. These pumps are located in the galley, the aft cabins
and the head. These pumps will serve as backups in the event of a
pressure failure but also can be used to conserve water usage by turning
of the pressure system.
The salt water system is an on demand pressure system with three taps. One
in the anchor locker for anchor and deck washdown, one in the stern for
deck wash down and one in the galley.
Dimensions
Length overall: 56.0
Length fairbody: 54.5
Length waterline: 53.0
Maximum beam: 14.7
Draft:  9.6
Displacement: 21,000
Ballast: 9280
Water ballast:1600 lbs per side
Sail area: working = 1480, maximum offwind = 3094
I:  60.5 J:26  P:57.6  E:20.5
Hull color: Blue
Engine
70 hp Isuzu
4JB1 Transmission
Hearth HBW 250
Fwd. Reduction Ratio – 2.01/1.00
Shaft – 1 3/8″ Aquamet 22
Strut – Cast Bronze
Propeller-Max-prop
Accommodations
3 stateroom, one forward, 2 aft
One head, lavac electric
Separate stall shower
Heating system: 30000 BTU Webasto DBW90 with four radiator fans
Hotwater – ll gallon Torrid with Stainless Steel Jacket. Tank is heated
by either shore power or Webasto Heater.
Galley
5.7 cubic foot box in galley for refrigerated items cooled by an
evaporator plate
4.5 cubic foot freezer box in galley cooled by an evaporator plate
All boxes have at least four inches of foam insulation surrounding them
Compressor is a Glacier bay system, water cooled.
Force 10 three burner stove with oven and broiler in Galley fueled by
propane.
Four 10lb. aluminium propane bottles with regulator and solenoid in
helmsman seat lockers

Tankage
Fuel:  133 total gallons, in two 60 gallon integral tanks and a 13
gallon stainless steel day tank
Water: 120 total gallons, in two 45 gallon integral tanks and one 20
gallon tanks
Holding: grey water, 20 gallons
Holding: black water, 54 gallons, integral
Electronic and navigation equipment
WS Sensor – B&G
Speed Sensor – B&G
Depth Sensor – B&G
Fluxgate Compass –B&G
Cockpit Displays – B&G
Four Dual Displays in Cockpit
Radar – Simrad
GPS – Garmin 120
VHF – Icom
AIS-Vesper marine
Electrical system
Shore power: 110v
House Bank – Three 8D Prevailer Gel Cells
Engine Starting Battery – Group 27 Prevailer Gel Cell
Electronics Buffer Battery – Group 27 Prevailer Gel Cell
Alternators and Charging
Main Alternator – Balmar 200 Amp directly charging the house bank
Secondary Alternator – 35 Amp charges the engine starting battery and
electronics buffer battery.
The secondary alternator can charge all banks and the engine can be
started and the electronics can run just from the house bank.
Shoreside charging is done by the 2500 watt Heart Inverter which has a
built in three step multi level 130 amp charger.
120 AC system
Shore Power is supplied by a 30 amp supply
110 AC can be supplied by either the 30 amp shore power supply or the
2500 Watt Heart Inverter.
The Inverter drives both the 110 refrigeration and the electronically
actuated ball valves.
The Inverter is managed by the Link 2000 mounted directly in the panel
and charging is supplied by the inverter.
Distribution
Distribution is by two custom panels by M and I Electronics. One panel
is for the 12 volt DC distribution and one panel is for AC distribution.

Deck equipment
6 – 8″ Schaffer Aluminium Cleats
30″ High Schaffer lifeline stanchions with boarding gates
Custom made bow and stern pulpits
Swim Step off of Dinghy Garage
4 – Lewmar Coastline 040
4 – Lewmar Coastline 010
6 – Lewmar Coastline 020
2- Lewmar Atlantic 010
1- Custom Sail Locker hatch by Lewmar with Kevlar and Nomex cover
instead of acylic for weight savings
All hatches except for the sail locker hatch have special order white
frames with custom rose bronze acrylic windows.
Sails and rigging
Sails
Main: 880 square foot Fusion by Quantum. Carbon fiber/Technora/Mylar laminate. Mast Track System is by Antal with Batten attachments by Sail
Power Systems. Mainsail has three sets of reef points.
Jibs: Working Jib is 600 square foot fusion by Quantum, with foam padded luff for
furling.
3 spinnakers of various sizes and weights
1 Code Zero mylar laminate on furler
1 Storm Jib
1 Storm Staysail
1 Storm trysail
Winches
Jib Sheet – Harken 56STA
(2) Main Sheet – Harken 53STA
Main Traveler – Harken 45STA
Halyard – Harken 45STA Electric
Spars and rigging
Spar – Carbon Fiber Spar by Hall spars, dual spreader with running backstays. Six Lewmar Halyard Clutches
on mast. Lazy Jacks with internal mast feed act as topping lift and
assist in furling.
Standing Rigging – All standing rigging is rod rigging by Navtec with the exception of the removable inner forestay, which is Kevlar
Runners – Running Backstays are Kevlar by Navtec.
Boom – Carbon fiber boom with foam core reinforced with plywood in high
stress areas.
Running Rigging – All Running is by Samson as noted below:
Main Halyard – 7/16″ UltraTech
Jib Halyard – 3/8″ UltraTech
Spin Halyard – 5/16″ Spectron dacron cover
Genoa Halyard – 5/16″ Spectron dacron cover
Mainsheet Sheet – 1/2″ XLS
Main Traveler – 7/16″ XLS
Running Backstays – 1/2″ UltraTech
Jib Sheets- – 9/16″ XLS
Spinnaker Sheets – 1/2″ XLS
Pole – Carbon fiber bow launched asymmetrical spinnaker pole. Pole is
extended by single line pull.
Water ballast
Port and Starboard Ballast Tanks of 200 gallons each
Electronically activated by instantaneous push buttons in cockpit arch
mounted in custom panels by M and I electronics.
1/2 hp. 12 volt Leeson motor driving a centrifugal pump rated at 60 GPM.

6 electronically actuated ball valves by Harrington
Effector Flow sensor on pump intake controls fill, empty, transfer
cycles and protects pump.
Koyo Programmable Logic Controller controls and coordinates the
automatic operation of the system.
Steering
Dual rudders. Rudders are asymmetrical to provide mild lift.
Rudders are by Advanced Composites and have 3.5″ outside diameter shaft
with an autoclaved carbon wall thickness of .875″.
Steering system has dual outboard pedestals and is a rod linked cobra
system by Whitlock with rack and pinion inputs in the pedestal heads.
There are two 36″ destroyer type wheels.
Each pedestal has a Ritchie Compass mounted in the pedestal.

bravo. somebody else mentioned this may be one of the best boat reviews ever written. I concur. and on some other thread people are musing about building their own perfect boats. so. wtf. why would I want to design and build my own boat when Paul can do it so much better. lol. what a machine! absolutely spectacular.

 

[ProaSailor]

why would I want to design and build my own boat when Paul can do it so much better.

So true.  And yet...  I've met a few boat builders who believe that only those who build boats are qualified to call themselves sailors.  Sounded like arrogant idiot talk to me but personal beliefs are like that, deep and unequivocal.

Design and Engineering Process – The RipTide 55 used a paperless design
and engineering process. The design, drawing and engineering process was
integrated into one process and was all done on the computer. 

 

[MFH125]

But,  help me with the SA/D above, I'm getting wonky low numbers for U and D wind.  The SA is square feet right, and weight in lbs?

You're right, those numbers have to be in square feet and pounds.  With a displacement of 21,000 lbs. and 1480 sq.ft. of upwind sail area, that's a DLR of 63 and SA/D = 31.

Those numbers seemed, ummm... optimistic, so I checked Bieker's website which gives a more reasonable displacement of 24,000 lbs and an upwind sail area of 1362 sq.ft.  That's a DLR of 72 and a SA/D of 24.

My guess is that 21,000 is the lightship displacement, and 24,000 lbs the half-load displacement.  1362 comes directly from the I,J, P, and E values, so presumably 1480 sq.ft. includes the mainsail roach (maybe some jib overlap too?) -- in which case the SA/D at half-load is 28.

 

[MFH125]

How about TEJST, a Swedish sailing canoe?





More info here: http://www.lunne.se/lunne/Tejst.html

 

[Matagi]

Stefan Züst did a very fine interpretation of a sailing canoe, he is one fine boatbuilder.

 

[slap]

6 minutes ago, Matagi said:

Stefan Züst did a very fine interpretation of a sailing canoe, he is one fine boatbuilder.

Looks a bit like a smaller modernized 110.  

 

[Cruisin Loser]

Looks a bit like a smaller modernized 110.  

My second sailboat, after my Beetle Cat. 

 

[MFH125]

22 minutes ago, Matagi said:

Stefan Züst did a very fine interpretation of a sailing canoe, he is one fine boatbuilder.

I like the sliding rowing seat that fits over the centerboard case.  Saves the weight of an outboard, and gives you something better than leaning over the side paddling with a floorboard.

 

[Whinging Pom]

They look a bit porky to be a sailing canoe ...

I had a go in one years ago. Like sailing a proa with no ama.

 

[Jud - s/v Sputnik]

Hogfish Maximus

Lots of cool qualities to admire. The name, maybe not so much

http://chrismorejohn.blogspot.com/2015/07/hogfish-maximus-details.html?m=1

 

[Voiled]

Lots of cool qualities to admire. The name, maybe not so much

Hey, i like that name. And she deserves a better picture:

 

[Jud - s/v Sputnik]

Hey, i like that name. And she deserves a better picture:

View attachment 479089

I was partly jesting - I like the name in that it’s suitable, and original.  But won’t appeal to the yacht crowd

Nice shot!  
 

BTW, is the hull glass over ply?

 

[Voiled]

Found this on that other site:

"The bottom of the Hogfish designs are made from 3 layers of marine grade plywood glued with 2 part epoxy. Then glassed over with 4 layers of 1 1/2 oz. Matt with a 10 oz. cloth to finish. I use polyester resin. On HFM I used vynelester as that's what I was building my flats boats with."

 

[SloopJonB]

View attachment 479089

The name is every bit as graceful as the boat.

 

[Jud - s/v Sputnik]

The name is every bit as graceful as the boat.

But she’s well proven as an ocean-crosser and a very capable cruiser, which ultimately is really all that matters...

 

[Kris Cringle]

If you have any friends with the new 'bongo board' sole adjusters;



,...there is great Christmas gift for winter practice to help you stay on deck next season. It's not like riding a bike! 

 

[longy]

^^ Typical owner - doesn't know how to adjust his own gear. Could at least level out the board.

 

[MauiPunter]

You would hope that it goes the other way as well if you wanted to steer from the lowside.