Jump to content

A very one design, the rebuild..


Recommended Posts

OK then,  this goes back to 1996, when I took a job in Saudi Arabia.  This was pre satellite TV, pre internet, days in Saudi. 

Needless to say within 2 days I was down at the company Baech, sailing wayfarers or lasers.. I was glad to find two boats being built inside the company accommodation compound,  just fifty feet from my allocated room. 

Once settled in and beginning to get bored,  I decided to build my own boat..  But what..

  Back around 1977 I was very interested in the mini America's cup boats, like the illusion,  international 2.4mR, and Deception,  classes.  However,  I wanted something shaped more like our local boats on the Norfolk  broads,  E.G. the white boat, http://www.ybod.org.uk/  not a pregnant whale. 

After 3 months, of sketches, models and scrapped ideas,  I came up with 16ft long, with the center section being 4ft wide,  1 foot flat centre at bottom , a 18inch radius curve,  up to a 9inch verticle plank. 1ft wide side decks, two foot wide cockpit. I and SWMBO would be sat tandem style,  with me steering with my feet,  and both of us handling the ropes.. 

While preparations were being made, I came home on holiday to find my clubs dinghy classes  had all but gone..  There just weren't any entrants,. partly due to a entire class being dsq d for roll tacking their way round the course, when there was no wind.

 At this point I'll point out our main dinghy class is allcomers B,  boats under 17.5ft..

Therefore on returning to Saudi I extended the design to 18ft, to enter Allcomers A boats over 17.5ft..

There are no photos of the boats construction, I arrived in Saudi the week after they blew up that tower block being used for USA troop accommodation,  our compound was about a mile away.  Taking my camera to Saudi in that security situation was not advisable... 

So what follows are photos and story of the current rebuild.. With a bit of back ground information.. 

Link to post
Share on other sites

First some notes on construction

The hull was constructed up side down of stitch and glue plywood. T,  several trestles were laid out,  next to the other boats under construction.  Onto which,  two longitudinal nine inch wide 16ft long planks  were set, the bow end stitched together.  Five foot from the bow they were 2ft apart to form the cockpit sides, that width was taken right back to the stern. 

Onto that was interlocked,  6 ring frames and a retrousse stern.

Then the two nine inch side planks were sown onto interlocking tabs, followed by the 1ft wide bottom plank for narrowing at the ends.

Then 4inch wide planks were sown on to the ring frames, each tailored to the previous plank due to the curves. The hull filled sanded, filled sanded, etc glassed over, Then the hull turned over,  decks fitted. 

Masts,  gaff and boom made,  a temporary sail made by a local car cover makers.. 

A steel lift plate was made by a local fabricators with ballast weights. 

Then the boat launched, a trial sailing made,  to large a turning circle,  caused by the rudder not being deep enough,  more ballast was needed which was expected,  you can always add more.. It's difficult to remove.. 

Then...... 

 

 

We were  moved to the mountains... 

So the boat wasn't sailed again in Saudi,  I got it shipped back back from Saudi in a container,  given a six week shipping time.. It arrived in two,  saw I had to rush around to hire a suitable tow truck.. 

It was then taken home and put in a shed... A week later I was "volunteered" to crew a Yeoman 20ft Keel boat,  18years later I'm still crewing that boat every winter.  The summers for 12years were spent mostly crewing / helming other yeoman I ended up national class chairman for 4 years without ever owning one. 

While typing this I've just received  a bad phone call, the father of the owner of the yeoman I crew in the winter has informed me my helm has been in a major accident on his motorcycle . Further typing to night is suspended.. 

 

 

Link to post
Share on other sites

I note that above I've missed out the fitting of some stringers.... 

Anyway  15years ago  my sailing club started a sailing school,  during the summer every Thursday afternoon / evening,  we have up to 80 children learning to sail,  this was soon extended to include teaching adults in the larger dinghies,  in keelboats , and now motorboats.  All to full RYA certification. 

This has now meant allcomers B is now one of the biggest classes. 

A few years ago I decided, which ever boat owner stopped sailing first summer or winter,  I would use that sailing season to get my boat sorted and on the water.. It was the summer  sailor who stopped after his wife had a cancer scare,  and he switched to motorboating which she would take part in. 

Allcomers A has one one hour race each Sunday,  I could compete in two more races but there would be nothing to compete for as the others went for class trophies. 

Allcomers B, has four races each Sunday although,  inside that there are class and allcomers trophies. 

I had made provision to remove the centre 2ft and that's what I've done.. 

This first photo was taken just after I had just "glued" the two half together.  Earlier photos were lost because the tablet computer they were on,  got broken.. 

The join is the clean patch round the middle. 

 

 

IMG_20180831_140024.jpg

Link to post
Share on other sites

How I approached the rebuild. 

The boat was placed on a wooden framework,  of 1/34 X 3 1/2 beams one foot off the floor. 

Two under the hull,  one each side just below deck level,  one each side of the cockpit combing,  two on top .

The skin was measured and marked up,  for the two cuts round the hull,  and the stringers. 

A week later I remeasured and checked the markings.  Then using a mini disc saw with adjustable depth.  The skin was cut off in sections. Then the skin strips on the stringers removed. 

At this point SWMBOs family had two seriously Ill Elder members,  eventually followed by their deaths this took much of our time for 18months, with 400mile return trips to visit them.  So no work on the boat was done for the duration.. 

A couple of pictures taken today... 

IMG_20190901_091040_1_compress71.jpg

IMG_20190901_091033_compress54.jpg

Yes the deck is going to be sanded off and revarnished 

Link to post
Share on other sites

Last summer I returned to the boat rebuild. 

The deck, cockpit and stringers,  were marked off for cutting,  these cuts were anything up to 2ft offset from the hull join.  Again a week later,  I remeasured  the markings before cutting... 

The cutting was quite intricate along deck to hull  and deck to cockpit  sides, requiring the use of a jigsaw,  hand saw,  and a Japanese pull saw. 

This left the centreboard box, this marked was off leaving 3inches each side of the old box. Cutting this fried a jigsaw,  it was built of layers of ply and glassfibre.  With a tufnol lining. 

Then 4 blocks of wood were arranged with yard long threaded rods through them. The blocks were arranged,  top and bottom of the ring frames either side of the cutting. 

I sat in the back with a spanner, tightening each nut, one at a time. Every so often there would be a creak  and the  halves would move together.. As they got closer, a board was put in the remains of the centreboard box to keep things lined up.   Eventually they were touching in places,  so i ran a grinding bit round the join making it even. Then a final tighten up. 

On the outside of the join,  all paint filler and glassfibre was removed. . Fibreglass tape was resined on,  sanded, filled,  then another tape was put on, sanded filled,  sanded filled,  and a base coat of paint applied.

That is the first photo shown.. 

Then stringers were doubled  and glassed over. A most uncomfortable time was then spent lying in the hull bonding all the joins on the underside of the decks.

Thickened resin was forced in the the hull join,  then glassed over several times. 

That was the end of last year's rebuilding, 

During the winter my unfortunate sailing compatriot,  gave me a kestrel dinghy mast and boom.  He was getting threats from his parents about removing it from their garden. He hadn't had a kestrel in nearly 20 years. http://www.kestrel.org.uk/

The kestrel is 15ft l6inches long,  and weighs about a 1/4ton including crew,  

My boat,  16ft long,  and should weigh 1/2 a ton including  me. 

The mast is 23ft long,  weighs 18lbs, a lot less than my wooden mast and gaff of about the same height. 

The boom is about 9ft long.. 

A picture,  the stern,  no the left-hand side isn't dark,  its a poor photo. 

.

 

IMG_20190901_091043_1_compress16.jpg

Link to post
Share on other sites

And so to this year, 

The remaining bit of centreboard box,  and the Two ring frames inside the cockpit sides were cut out. The stub of the box was ground down to level with the ring frames. Ply was inserted into the hole for the centreboard and bonded in. 

The old rudder was a cassette that dropped in,  this of course is excess weight.  So the cassette was removed and parts used to fill the hole the outside,  glassed over, filled sanded etc

The interior around the rudder box has yet to be sanded filled painted. 

The rudder itself is heavy,  the shaft is a section of scaffolding pole,  you use what is available in Saudi. 

The tabernacle was modified for the new mast,  I had a spare mast foot holder that fitted,  I then made a insert for the top to hold the mast. The old mast being 4 inches square at that point the new mast being 2.5 inches wide.. 

Come to that,  the stay plates you can see,  are round bars of Stainless Steel from the inside of a disused industrial air conditioner.. 

Today I made to size,  then bonded in bearers for the keel bolts,  photos will be next week. I take photos first thing leaving it to later, would guarantee me getting something sticky on this tablet. 

Link to post
Share on other sites

Many moons after I designed and built my boat, I returned to the UK, with the internet now available I found freeship. All the measurements were entered in, to the best of my lack of ability and the printout is shown below.  The figures produced by the programme also agreed with my many hours of calculations:).. I just wish the programme had been available in the first place..

 

blue moon 16.jpg

Link to post
Share on other sites

Where I sail is mostly a river club, In the summer Racing changes from week to week. One Sunday may be round the cans outside the club, another may be on a small broad  1/2 a mile up river, and if the tide is right we race a civilised 7 or 8 miles to one pub or another, have lunch then race back..

The variety of sailing is one of the reasons I sail with this club, there are perhaps a half a dozen to choose from within 20 miles.. Below is a link to the club website, the Video on the front page shows the club. The races from the club  go up river  for a 1.5 miles, on the top right of the video you can see Black Horse broad, where we race also.  https://horning-sailing.club/ The down river races go in the opposite Direction, down through the village.

At the most intense during regatta week we can have 100 sailing boats in the 1.5 miles from the club going up river. Ranging from Optimists  to a 45ft Broads Cruiser. This is acompanied by hire and private motorboats which should be filing down each river bank.

 

One of the things I spent many hours working on was how to control the jib.

Most of the mini keel boats just use a small conventional Jib, but they are normally in comparitively open waters.

So the decision was to have a Self tacking jib, But what arrangement to have?

Eventually I settled on one  seen on Broads cruisers and on the international canoe.

There is no Jib stay while sailing, the jib halyard goes to the front of the Jib club.

The pivot point of the club is about a foot behind the leading edge, so as you tension the jib halyard, you tension the luff and to a lesser extent the leech. 1:4 in this case at the moment.

Another oddity is the position of the jib is controlled by the Windward sheet, this is so you can goose wing the jib when required..

Hopefully below will be the picture of the arrangement on an international canoe..

 

intcanoe[1].jpg

Link to post
Share on other sites

The observant of you will have noticed I've just posted the wrong picture of the International canoe with only almost the arrangement I described. Now of course I can't find the correct picture . So here is a link to a  Swallow Yachts, Bay Raider Expedition 20, with this arrangement.

https://www.swallowyachtsassociation.org/?page_id=1087

 

 

Link to post
Share on other sites

The system mostly used on recent canoes isn't quite as you describe. The jib halyard arrangements are conventional and the jib tacks down on the centreline. The line to the end of the spar is a separate control line that is effectively a kicking strap/vang for the jib. Its not a club foot as per Hunters etc.

Link to post
Share on other sites

I'd agree the method I've chosen is not the same as most ICs with some sort of vang/ club foot  I saw at least one ( in photos) using what I've described. whether that was just a trial or something they were going to use permanently I don't know. The photo I wrongly posted of an IC uses a method as you described. 

I have the problem of converting a 30+year old aluminium mast for the purpose,  it's tapered for about  the top quarter and very slender . I'm very loathe to drill any more holes in the top quarter  so as to have both a halyard,  and a separate Vang control.  Already I have  to add a topping lift / lazy Jack system for the main as sitting inside, as I need to drop the main without burying myself in Sail, before heading for the quay .

I'm loosing a lot of sail area  going self tacking, several alternative systems were looked at such as. 

Having a bowsprit below the Vang / club foot,  to allow   a forestay forward of the jib, 

Disadvantage : extra holes in mast, the sail area would be slightly reduced as the jib would have to be above  the bowsprit and Vang / club foot.  it would put more forward pull on  the mast,   the boats annual  broads tax would go up ( calculated  max fixed length X Max width) .

Having the pivot  of the club at its forward edge, that pivot being just behind the forestay on the bow,  

Disadvantage : reduced sail area,  requires a track and possibly a down haul onto the track to control the leech, being such a narrow boat,  that would only cover very close hauled. 

 

I would welcome  any other solution to the problems that you or others could suggest.. 

Link to post
Share on other sites

Just about every possible jib arrangement has been tried on ICs at one time or another, so you might have seen the old style club foot. The classic arrangement for a forestay, as I'm sure you know, was to offset the forestay anchor off to one side so it cleared the jib.

What have you got in the way of holes/halyards/ fastening points in the hounds area? a spinnaker halyard would be ideal, but I've simply hung an extra block off the mast by passing a piece of rope through above the T terminals. If you use 2mm dyneema for all but the last foot or two the windage from an external control line running down the mast would be pretty nominal.

Link to post
Share on other sites

There is a very strange stiff thick  wire arrangement that used to hold the spinnaker top block forward off the mast by 3 or 4 inches just above the old jib forestay mount. 

One thing I've realized having woken at stupid o'clock this morning,  the topping lift doesn't need to the absolute top of the mast, I'm going to look at the side stay / mast fitting, just as I leave for work. To see if I can fit a plate each side to hold a block one side and tie off point the other.. 

It very easy to miss the obvious when there is no one around to bounce ideas off of. 

 

Link to post
Share on other sites

So out in the pouring rain walking the dog round the garden, and a diversion to inspect the mast, yes theres is room to attach the topping lift to the side stay mounting mounts just needs a couple of larger pin and split pins plus a couple of stain less extender plates of a couple of inches long. I can cut up and old dinghy stay plate for that..

Noticed, that the top of the mast has a small flat welded over the end probably that stops the end of the mast unbending and letting the main halyard sheave drop out. I wonder how much stress that is under.. I suspect not a lot..

 Could I rivet a plate to the top and have an eye forward of the mast?

This would mean changing from a fractional rig to a full height jib. it would regain more of the lost sail area, but would it over stress the mast?

I could hang a double block from the eye, use one sheave for the Jib halyard , the other for the vang / jub club control line..

Ideas Ideas...

It's a good job I haven't ordered the keel yet, as it will change the centre of effort..

Link to post
Share on other sites

Well, i did a lot of thinking about self tacking jib arrangements for my IC and in the end decided that the best compromise was going to be the arrangement everyone else has moved to. 

I eliminated the old style club foot with the tack part way along the spar as being too inflexible. If you have no adjustment of leech tension then the jib is almost never set right, and if you do then the addition of rig tension into the leech tension equation is a awkward complication.

 

Link to post
Share on other sites

I'm intending to have a furler and an outhaul on the club,  as I need to be able to get rid of sail area in a hurry .

Sat down inside the hull to steer, does mean going alongside  will be a tricky business even with the sail furled..

Link to post
Share on other sites

To my mind your spinnaker crane is ideal to hang a micro block off for the vang control. I'd probably try gluing a plastic fairlead to the mast so the return is alongside the spar, and not bother to run it inside the tube. Alternatively just attach another micro block or even one of those trendy low friction rings to a shroud anchor.

If you're going to furl the jib reckon you cant have the pivot back from the tack.

  • Like 1
Link to post
Share on other sites

Gust response.. I hadn't thought of that, one pair of hands and two ropes to ease rapidly at the same time. Although the hulls respose to a gust will be somewhat slower than an IC as it will have, I hope, 200-250Kg of lead and steel hanging off the bottom..

Thinking about it, I've chopped out / removed and added just about all I'm going to.  It might be time to get the strain gauge out again and use the crane (car engine type  two A frames with a cross bar) to weigh the hull with all it's gear, and separately... me. To see what ballast she needs, and to find out what the final Ballast /displacement / Sail area, ratios will be..

 

 A minor piece of information,  a while ago I managed to buy very cheaply an old set of sails for this rig. They are in good condition but tired. I wasn't going to risk a new set of sails, until all other bugs in the boat are Ironed out..

The main will be used As is.

The jib will require shortening along the foot, this will be nowhere as good as a new sail and the shape probably won't be right, But it will do for the trial period..

Once some sailing has been done new sails can be ordered, the main foot is short of the length of the boom by about a foot, so,  if needed that foot can be extended by say 9 inches if required.. (The booms of the period for this class, were made like that..)

She will have to have some method of reefing the main, probably sail ties, rather than holes in the main for lacing up..

If She needs more Jib, then I will have consider using a full height jib..

Link to post
Share on other sites

Congratulations to  Ian Dobson and Richard Wagstaff Helm and crew of a Fireball, they are now world Champions Having won the North American Championships followed by the Worlds at Pointe Claire Yacht Club of Montreal .

Richard's mother is our club Secretary, She and his late father who died last year have been great supporters of our club..

1st GBR 15161 Ian Dobson, Richard Wagstaff, in Orchitis

Link to post
Share on other sites
On ‎9‎/‎3‎/‎2019 at 10:19 AM, The Q said:

Where I sail is mostly a river club, In the summer Racing changes from week to week. One Sunday may be round the cans outside the club, another may be on a small broad  1/2 a mile up river, and if the tide is right we race a civilised 7 or 8 miles to one pub or another, have lunch then race back..

The variety of sailing is one of the reasons I sail with this club, there are perhaps a half a dozen to choose from within 20 miles.. Below is a link to the club website, the Video on the front page shows the club. The races from the club  go up river  for a 1.5 miles, on the top right of the video you can see Black Horse broad, where we race also.  https://horning-sailing.club/ The down river races go in the opposite Direction, down through the village.

At the most intense during regatta week we can have 100 sailing boats in the 1.5 miles from the club going up river. Ranging from Optimists  to a 45ft Broads Cruiser. This is acompanied by hire and private motorboats which should be filing down each river bank.

 

One of the things I spent many hours working on was how to control the jib.

Most of the mini keel boats just use a small conventional Jib, but they are normally in comparitively open waters.

So the decision was to have a Self tacking jib, But what arrangement to have?

Eventually I settled on one  seen on Broads cruisers and on the international canoe.

There is no Jib stay while sailing, the jib halyard goes to the front of the Jib club.

The pivot point of the club is about a foot behind the leading edge, so as you tension the jib halyard, you tension the luff and to a lesser extent the leech. 1:4 in this case at the moment.

Another oddity is the position of the jib is controlled by the Windward sheet, this is so you can goose wing the jib when required..

Hopefully below will be the picture of the arrangement on an international canoe..

 

intcanoe[1].jpg

just as an aside that canoe was designed and built in Norfolk as well...

  • Like 2
Link to post
Share on other sites

The good news Is my winter sailing compatriot has been moved from the specialist hospital of Addenbrookes to the local area Hospital of the Norfolk and Norwich. I'll try to go for a visit some time Saturday..

I've found a couple of older photos, 1 is as I came  back to working one her after the enforced Break. i.e covered over and the undergrowth encroaching.

The other is looking down the "tunnel" of the hull from the stern, you can see one of the lumps of wood and bolt heads in place that I cramped her up with iandithe just blocking part of the view.

 

IMG_20180708_084235.jpg

IMG_20180708_084632.jpg

Link to post
Share on other sites
On 9/2/2019 at 2:31 AM, The Q said:

Many moons after I designed and built my boat, I returned to the UK, with the internet now available I found freeship. All the measurements were entered in, to the best of my lack of ability and the printout is shown below.  The figures produced by the programme also agreed with my many hours of calculations:).. I just wish the programme had been available in the first place..

 

blue moon 16.jpg

It's a cool hull. Reminds me of 18th century warships.

Did the program give you some trouble replicating the shape right up in the bow? Sometimes that takes some fiddling.

Link to post
Share on other sites
59 minutes ago, fastyacht said:
On 9/2/2019 at 2:31 AM, The Q said:

blue moon 16.jpg

It's a cool hull. Reminds me of 18th century warships.

Did the program give you some trouble replicating the shape right up in the bow? Sometimes that takes some fiddling.

FreeShip is awesome. I have done exactly one boat design that was actually built with it, but I have modelled a bunch of other fancy stuff that I molded in fiberglass (including a custom tray for electronics. And I have a couple dozen designs that I fiddle with, for fun and the possibility that I -might- build one of them, one day.............

FB- Doug

Link to post
Share on other sites

Oh yes, I didn't get the bow shape right in Freeship, the hull cross section of the boat is a bit concave just behind the bow above the water line. I just couldn't replicate that, also in Freeship to get the underwater hull shape right, the centre three deck level cross  sections vary more  than the straight of the boat. I was mostly concerned with finding out if my displacement calculations were correct, as I have yet to have  the new keel made..

I too have had several other designs kicking around, on freeship, Doubt any will get built, I'm struggling to find time to finish the rebuild of this one..

I note my scan of the drawing of the sail plan the main didn't come out very well, It is there (just).

Link to post
Share on other sites
3 hours ago, The Q said:

Oh yes, I didn't get the bow shape right in Freeship, the hull cross section of the boat is a bit concave just behind the bow above the water line. I just couldn't replicate that, also in Freeship to get the underwater hull shape right, the centre three deck level cross  sections vary more  than the straight of the boat. I was mostly concerned with finding out if my displacement calculations were correct, as I have yet to have  the new keel made..

I too have had several other designs kicking around, on freeship, Doubt any will get built, I'm struggling to find time to finish the rebuild of this one..

I note my scan of the drawing of the sail plan the main didn't come out very well, It is there (just).

One trick I have learned in FreeShip is that the sections don't have to be perpendicular/straight. You can put the line of control points anywhere you want. You can also control the "pull" of the control points on the surface but the few times I monkeyed with that, it became an irretrievable unholy mess.

I like the hull, it looks like a great low-wetted surface river sailer, very maneuverable.

FB- Doug

Link to post
Share on other sites
38 minutes ago, Steam Flyer said:

One trick I have learned in FreeShip is that the sections don't have to be perpendicular/straight. You can put the line of control points anywhere you want. You can also control the "pull" of the control points on the surface but the few times I monkeyed with that, it became an irretrievable unholy mess.

I like the hull, it looks like a great low-wetted surface river sailer, very maneuverable.

FB- Doug

Yes I had several messes and had to return to the basic model.. I was always gettinng indicated leaks,,,

The low wetted area and manouverabiliy are some of my requirements, we've often not a lot of wind, and if you looked at the club video up above you'll have realized we do a lot of tacking... If you've not seen any of my other posts about the 3 rivers race, heres an example of our sailing

I'm in there in Y 219,  I now Officiate running anothe guardship elsewhere..

Link to post
Share on other sites
24 minutes ago, The Q said:

Yes I had several messes and had to return to the basic model.. I was always gettinng indicated leaks,,,

The low wetted area and manouverabiliy are some of my requirements, we've often not a lot of wind, and if you looked at the club video up above you'll have realized we do a lot of tacking... If you've not seen any of my other posts about the 3 rivers race, heres an example of our sailing

I'm in there in Y 219,  I now Officiate running anothe guardship elsewhere..

I love the videos of this race, and many years ago read about it in 'Coarse Cruising.'

One way to avoid the indicated leak problem is to always "extrude" edges into a new section... transom, gun'l, deck, cockpit, etc. You can start a new layer at the same time so you can make them a different color or seperate them in view windows. I have had very little luck matching new surfaces edge-to-edge.

Here's a couple of the ones I've been fiddling with:

6.6mCatboat_v02dsk_Linesplan.jpg.d1d4b3efafe69de6437a55f6aba6bbe7.jpg596a427b8a6db_Sp-RwBoat4raid04-1d_Linesplan.jpg.ffefc19cacdac37e682fe9d7a5352ea3.jpg

The catboat on the left was used as the basis for a radio-controlled model my father built, believing that he taught me everything I know he changed the hull design on the fly as he went. It ended up quite nice and I'm glad to give him the credit.

The other is intended as a beachable raid/expedition style daysailer/overnighter, as close to a sportboat as possible while still being safe and practical to take around rough edges away from civilization.The next iteration in progress has a bit fuller forward sections, a bit less flare, a deeper cockpit, and I'm working on the ergonomics of putting a sliding seat rowing station amidships. The hull out to the edge of the flares is one layer, the transom and gun'l were done as layers unto themselves, the deck and coaming and cabin bubble is one layer, and the bulkhead/cockpit is one layer. All were extruded from the whole edge of the prior layer starting with the hull.

I know it's not really a cruiser but I bet you could take your plan over to Cruising Anarchy and get Bob Perry's critique.... I have some notes I shamelessly picked up from there, if I ever get as far as planning a rig & foils...

FB- Doug

 

Link to post
Share on other sites
5 hours ago, The Q said:

Oh yes, I didn't get the bow shape right in Freeship, the hull cross section of the boat is a bit concave just behind the bow above the water line. I just couldn't replicate that, also in Freeship to get the underwater hull shape right, the centre three deck level cross  sections vary more  than the straight of the boat. I was mostly concerned with finding out if my displacement calculations were correct, as I have yet to have  the new keel made..

I too have had several other designs kicking around, on freeship, Doubt any will get built, I'm struggling to find time to finish the rebuild of this one..

I note my scan of the drawing of the sail plan the main didn't come out very well, It is there (just).

 

2 hours ago, Steam Flyer said:

One trick I have learned in FreeShip is that the sections don't have to be perpendicular/straight. You can put the line of control points anywhere you want. You can also control the "pull" of the control points on the surface but the few times I monkeyed with that, it became an irretrievable unholy mess.

I like the hull, it looks like a great low-wetted surface river sailer, very maneuverable.

FB- Doug

The problems are all due to the NURBS paradigm. Real materials do not behave like NURBS. To make a "fair NURBS surface you need as close to perfect rectangles of equal dimensions as possible. This is why you need to cant the curves at the ends.  The business with the weight on the points is useful but mmost of the time it blows up. Takes some time to learn how to use weighting of points effectively.

If you want to know how surface models work and not work, read Steve Hollister's papers on the subject:
http://newavesys.com/secrets.htm

Link to post
Share on other sites

With a bit longer cabin, the top one is very like many of the broads hire  sailing boats, though they tend to have a "Pop Top", that is the centre or whole of the roof lifts to give full headroom when moored. Canvas infills for the sides.. Either propped up by supports in the corners, or tilted up at the back hinged the front, rarely, some supported by the Boom.

 

Just noticed I've mistyped it should say I was there is Y 210 (not 219)

  • Like 1
Link to post
Share on other sites

I spent yesterday afternoon visiting my sailing compatriot, 

Fractured skull, Broken right wrist and hand now pinned and plastered, fractured pelvis,  broken right femur, now pinned,  broken right ankle pinned and wired in special holder..  He won't be sailing for a while. 

 

Today's boat work,  mast put up, boat loaded with everything needed to sail her. Boat lifted with strain gauge on.. 

287kg, of which 12kg is the support frame. So 275 kg,  add me 115kg, 390kg, design weight 500kg. So only ballast of 110kg. I need to add more.. 

I could loose at least 10kg from the all up weight by replacing the rudder with a foam sandwich one,  and a narrower shaft. 

I could loose  at least 15kg from the all up weight from me,   it would please the quack.. 

Next week the quest to loose more, where's the hole saw.. 

During this I got brambled, so out with the loppers and I also ended up clearing the large amount of accumulated wood,  some from the support framework when she was cut in half,  some from bits cut off.  All sorted into goodwood and firewood.. 

We then laid out the jib,  to find its not a full size kestrel jib,  luckily it was still bigger than needed, so a foot was cut off the err... foot all the way up to nothing removed at the head.   instead of the 4 foot off the foot of a full size jib. This does mean there will be less incorrect shape, than there would have been altering a full size jib. 

A couple of pictures with the mast up one grounded one hanging from the crane.. 

 

 

IMG_20190908_093217_compress86.jpg

IMG_20190908_092524_compress44.jpg

  • Like 1
Link to post
Share on other sites

Further inspection of the kestrel class rules show this jib is 26inches short on the leech too.  It was originally  34sqft against a class Max of 50 sqft.

This means that when I eventually get a set of sails made,  the jib will be taller and slightly bigger something I'll have to consider in the trials. 

Link to post
Share on other sites

Well today's work was originally going to be cutting the keel to shape.  But then I realized that can be done anytime,  while hull work requires good weather.. 


While uncovering the boat I managed to cut open my thumb on a old rivet on the boom not a good start.. 

The first thing was to lower the mast which had been left up since last week.,  I then measured up for the main halyard sheave and pin with some calipers. It's remarkably small.. 19mm with a 3mm pin. I'm going internet searching to look for a replacement shortly. 
It took nearly an hour and a half before I got going.. 


So the grinder ( and drill With flap wheel ) was employed cutting and grinding the rudder case and the aft compartment and generally smoothing things. .  Many stops to  allow clouds of dust and smoke to clear.. 


 After three or so hours the grinder slipped from my grasp and eat it's own cable.  The RCD and fuse did their stuff,  I spent the next hour stripping the grinder and replacing the cable.. Once tested it was back to work,  after a while I needed to change the disk.. It was jammed, I bent the special spanner, so was the end of that for the day. A new spanner stronger has been ordered.


A final Bit of work was filing the old rivets on the boom... 

The picture of the day, the jib club Vang propped up by a brick as it in its raw state today.. 

IMG_20190915_132205_1_compress51.jpg

Link to post
Share on other sites
On 9/6/2019 at 11:25 PM, fastyacht said:

The problems are all due to the NURBS paradigm. Real materials do not behave like NURBS. To make a "fair NURBS surface you need as close to perfect rectangles of equal dimensions as possible. This is why you need to cant the curves at the ends.  The business with the weight on the points is useful but mmost of the time it blows up. Takes some time to learn how to use weighting of points effectively.

If you want to know how surface models work and not work, read Steve Hollister's papers on the subject:
http://newavesys.com/secrets.htm

Isn't Freeship based on subdivision surfaces, not NURBS?

Link to post
Share on other sites

The answer to Above I don't know, I just use it, if Fastyacht wishes to reply please do..

Meanwhile,  BEHIND YOU !!!!

Capture.JPG

While our (Horning Sailing clubs) Barts Bash was on This intruder came through.. 58ft 23tons of Norfolk Wherry.. The oppie needs to go round the buoy, the Wherry needs  to go off left of picture round a 90 Degree bend about level with the buoy.

 

Barts Bash= https://www.bartsbash.com/

  • Like 1
Link to post
Share on other sites

     I always thought that Delftship and Freeship were both Sub-D based but it seems that there is a bit more to it.

I think I need to step into what's becoming quite a discussion here.

Fist of all let me make one thing clear: It is not the Delft University of Technology selling open source software here. I've been an employee of the Delft University for more than a decade and my task was (amongst other things) to develop a software system that was easy to use by the University's students and it should have full 3D support. The University also had the need of access to the sourcecode of the program in order to plug in all kinds of research software developed by the Uni. Those were the main goals of starting the development of DELFTship, which actually started in 1996. The original DELFTship program does a lot more than just hull modeling.

I've been trying out all kinds of methods for hull design, including wireframe modeling, NURBS modeling and other methods and it proved that Subdivision Modeling was by far the easiest and most flexible way to do this. I was so taken by this way of surface modeling that I wanted to share and promote this by writing an open-source program to demonstrate it's capabilities. I decided to write a new hull modeling program from scratch. It was inspired by the technology I had adapted in DELFTship but improved it many fronts. In almost two years time I invested 1300+ hours of my spare time into the FREE!ship project, an avarage of almost two hours a day, every day and I consider that my contribution to the open-source community.

By no means I had foreseen the way the project was recieved and the speed which with the popularity of the program grew convinced me there was indeed a need for such a program. Surprisingly (to me) this was confirmed by the fact that FREE!ship is competing very well in the poll "Best Marine design software" as the sole free version between some commercial giants. After 11 years with the University I decided it was time to take a leap of faith and quit my job and start my own business. I have a business agreement with the Delft University which allows me to commercialize the technology that I've been developing for them over the years as well as the name DELFTship.

The most logical way for me to do this is to improve and incorporate it into what used to be FREE!ship. The first steps have been made by incorporating intact stability and tank modeling. Currently I'm working on longitudinal strength and damage stability which I'm hoping to release soon also. My decision does not mean that FREE!ship is no longer open-source. As others have pointed out already the published sourcecode is still available to anyone to modify, publish or do with it whatever they feel like. I just decided to make my new DELFTship project closed-source for obvious commercial reasons.

I just want to finish this of by thanking all of you who have been so supportive over the last two years, and hope this will put some rest in the discussion.
 
  • Like 2
Link to post
Share on other sites

Thanks for all Your efforts with freeship, as Blue moon is probably the only boat I'll ever have got to design and build,  a paid for programme would not be economic for me.  But I wish you all success with Delftship. 

Link to post
Share on other sites

And Now for something completely different.. If you happen to be in North Norfolk UK  on the 6th of October..

The big Day approaches our own                                   Broadland Model Railway  Club      show..

2019 Exhibition

Aylsham Model Railway Exhibition 2019

The 2019 Model Railway Exhibition, sponsored by the Bure Valley Railway, will be held again in

The Jubilee Centre,

Aylsham, NR11 6JG

 Saturday 5th October 

between 

10.00 and 16.00 (10am and 4pm).

Main parking at the Bure Valley Railway, disable parking  at the Jubilee centre.

 

The following layouts and traders are confirmed for 2019:

All Cars Stop Here OO Hong Kong influenced tram stop

Arlingham 4mm EM 50s/60s ex-GE branch

Barrow Fells 2mm N West Coast mainline modern

Bedford Road 7mm O Diesel Depot

Blacklade 4mm OO 85-90 or 2000-2007 North Midlands

Broad Oak 4mm OO Eastern Region ex Great Central

BVR in minature 7mm O 9Aylsham Station 2010-15

Cobbold’s Wharf 7mm S7 East Anglia based on Ipswich docks

Coltishall 4mm OO 60s/70s Coltishall, Norfolk

Gillsbrook 4mm OO ex-GE 50s/60s Essex/Hertfordshire

Hartenberg N Bavarian Era2 Tramway

Iceni Cement 4mm OO East Anglia 60s/70s

Jusabit MPD 7mm O Early BR motive power depot

Operation Abyss 4mm OO Wartime dockside

Ringsford 4mm OO East Anglia 50s/60s

Thomas and Friends Child friendly hands on

Traders:

Bob Pearman Books

Bure Valley Railway

Coast2Coaster

Dave Rowlands

Joe Lock

JustinCase

Train Tech

Demonstrations

Advent Modellers

Loco Doctor

Nigel Fisher

DCC

Societies

B17 Steam Loco Trust

Class 47 Preservation Project

Friends of the BVR

North Norfolk Model Engineers

We look forward to seeing you all there in October!

 

Link to post
Share on other sites

Back to rebuild  time,  

A total of two carrier bags of excess wood have been removed from the rudder box area, cut off,   ground down, smoothed off, and 3X holes cut through unneeded thickness of beam. A new set of quality holesaws did the job easily.  A small section of the hog needs finishing, it all needs final sand and paint. 

 

Next time should see that finished,  then I'll move onto the next compartment. 

 

Still can't get angle  grinder blade unstuck,  maximum force is just elongating toothed spanner holes. Everything tried heat, hammering,  oil.  If  I can't unstuck it when I come back from Scotland then a new grinder will have to be ordered. 

 

Come 14:00 I was knackered, I had to force myself to continue until I completed some essential  resin work. Needing a sit down before covering the boat up. 

 

Authority has been granted to purchase a garden marquee,  20ft by 10ft this will extend the rebuild season.  As yesterday's conversations with my injured sailing compatriot confirmed it's highly unlikely we will sail this winter season, giving me much more boat rebuild time.. 

Link to post
Share on other sites
3 hours ago, The Q said:

Still can't get angle  grinder blade unstuck, 

Can you try breaking up the blade and removing the bits with a sufficiently small cold chisel? I'd also try a drift on the 'nut' directly, not using the holes.

Link to post
Share on other sites

Breaking the blade is a possibility, but annoying, as it's a quality one, probably a third of the price I paid for the grinder. The "Nut" is round to start with, I'd have to make some sort of slot in it for the drift to impact on..

I'll probably go on using this grinder, as is, with the wood cutting blade on it until it is worn out , then smash the blade off..

Link to post
Share on other sites
On 9/16/2019 at 11:15 AM, Rasputin22 said:

     I always thought that Delftship and Freeship were both Sub-D based but it seems that there is a bit more to it.

I think I need to step into what's becoming quite a discussion here.

Fist of all let me make one thing clear: It is not the Delft University of Technology selling open source software here. I've been an employee of the Delft University for more than a decade and my task was (amongst other things) to develop a software system that was easy to use by the University's students and it should have full 3D support. The University also had the need of access to the sourcecode of the program in order to plug in all kinds of research software developed by the Uni. Those were the main goals of starting the development of DELFTship, which actually started in 1996. The original DELFTship program does a lot more than just hull modeling.

I've been trying out all kinds of methods for hull design, including wireframe modeling, NURBS modeling and other methods and it proved that Subdivision Modeling was by far the easiest and most flexible way to do this. I was so taken by this way of surface modeling that I wanted to share and promote this by writing an open-source program to demonstrate it's capabilities. I decided to write a new hull modeling program from scratch. It was inspired by the technology I had adapted in DELFTship but improved it many fronts. In almost two years time I invested 1300+ hours of my spare time into the FREE!ship project, an avarage of almost two hours a day, every day and I consider that my contribution to the open-source community.

By no means I had foreseen the way the project was recieved and the speed which with the popularity of the program grew convinced me there was indeed a need for such a program. Surprisingly (to me) this was confirmed by the fact that FREE!ship is competing very well in the poll "Best Marine design software" as the sole free version between some commercial giants. After 11 years with the University I decided it was time to take a leap of faith and quit my job and start my own business. I have a business agreement with the Delft University which allows me to commercialize the technology that I've been developing for them over the years as well as the name DELFTship.

The most logical way for me to do this is to improve and incorporate it into what used to be FREE!ship. The first steps have been made by incorporating intact stability and tank modeling. Currently I'm working on longitudinal strength and damage stability which I'm hoping to release soon also. My decision does not mean that FREE!ship is no longer open-source. As others have pointed out already the published sourcecode is still available to anyone to modify, publish or do with it whatever they feel like. I just decided to make my new DELFTship project closed-source for obvious commercial reasons.

I just want to finish this of by thanking all of you who have been so supportive over the last two years, and hope this will put some rest in the discussion.
 

Now I'm a bit confused.

Rasp, are you Martin, or are you quoting a thread that Martin wrote at BD.net?

I realize that whatever free program I was thinking of is neither freeship nor delftship. So many have come across my bow for only so brief encounters. Carene? I dunno.
At any rate NURBS are fundamentally annoying. But "easy" until they aren't. NAPA had the most powerful way---but at like 1 million dollars and 30k a year or something, it ain't gonna happen....except at large deep pocket shipyards (why I once used it and was trained in it). That program used curves, and then patches, and while it could be a lot of painful cut and try, the result was you could do anything that can be done my hand. Not so with Nurbs!--unless you "fake" nurbs together with non-perfect edges/matches and kludges.

Link to post
Share on other sites

     No, I'm not Martin, his name is at the bottom of the quote. I've tried Delftship and Freeship but I started with Maxsurf and ended up using Rhino3D and ORCA3D since 2001. Actually ORCA doesn't go back that far but I think it was RhinoMarine for a while. 

     Yeah, there are some no-no's when using NURBS like stacking control points for chines and singularities to make three sided panels. I got all upset on the Rhino webforum when some guy started calling some of my surfaces 'degenerate' (forefoot 2 rail sweep to a point) and got all butthurt until he was good enough to reveal the error of my ways. Somehow MaxSurf encouraged stacking of control points for chines which would raise all sorts of hell upon import to Rhino.

     I've been using Fusion 360 for a couple of years and it plays pretty well with Rhino but I don't think I will be doing any boat hulls in Fusion anytime soon!

Link to post
Share on other sites

Further to my notes on the small jib, which I think was for high wind strength,  I've been reading up on kestrel jibs and many are moving towards blade jibs, particularly those who sail on tight waters for ease of use and quick tacking.

 

  This weekend involved a 402 mile drive to visit my parents,  so no boat work has been done,  however much thought on control layout has been done. Sketches have been done and rope routes planned.

Originally I was going to have a control panel in front of me, similar to the various mini 12M classes,  however so as to not feel so enclosed in the boat, and not have so many ends of ropes all in the same area,  I've changed my mind.

Now I will have most controls on the cockpit combings just each side and in front of me.
So they will be, in nearest to me order, on each side,  jib sheet,  jib in or out haul,  then jib vang on one side.

At the front of the cockpit just by the mast, will be jib and main halyard,  topping lift and Cunningham,  

From the boom in front / above me, in nearest to me order,  mainsheet,  outhaul, kicking strap.

The mainsheet starts on the boom,  to the aft cockpit bulkhead back to the boom,  then along the boom to the block in front / above me.

I'm still working on the design  for the rudder controls but it's looking like a inclined forward slightly rotating post with cross bars for feet.  Then just each side of me,  handles attached to the rudder control wires,  as an auxiliary control..

Also dropped into the cockpit behind me,  are a permanently attached  small fender and aft mooring rope on each side.
In the forward corners on the cockpit another fender each side  and the forward mooring rope.

Link to post
Share on other sites
  • 3 weeks later...

No work has been carried out for a couple of weeks, last weekend I started suffering from a heavy cold,  of which is still causing me some breathing problems . I did however get out to buy a 4M by 6M marquee, today I started assembling this around the boat. That should be finished next weekend.

Why not tomorrow?  It's the start of Snowflake Sailing Clubs winter sailing season.  Which starts with the Tri-icycle, this is a 20 Mile passage race,  boats from 14ft to 45ft, if weather conditions are right from HSC to Potter and Acle bridges then back to the club.  See the map, which is actually that for the bigger 3rivers race. 

3RR_Map2.png

Link to post
Share on other sites
  • 1 month later...

No postings for a few weeks, as not much has been done, it took 3 weeks to get the marquee fully up due to time limits , the ground frames  are loaded up with sand bags to keep it in place. The marquee is currently surviving 44 mph Gusts expected to reach 55mph tomorrow afternoon.

This weekend I  took my injured sailing friend to the SC for a day out... There were about a dozen dinghys out who braved the first two races before abandoning the third as the gusts, were by then exceeding 35mph.

The rescue boats were busy!! a couple of picture, the second shot with added Yeoman keelboat is on the most sheltered part of the course, there's a bank of trees right of shot. 

 

The majority of the grinding down of lumps and bumps , has been completed in the rear 3 Sections, using the new angle grinder and a dremel to get into the corners, it's still not pretty and could be smoother , but it will do for now.. A patch coat of bilge paint has been appiled for the moment. Next weekend, I should do the actual area of the join and the section forward of that. Before it gets really painful working up in the bows..

79371920_1354132488073211_1424120497183916032_o[1].jpg

79432463_1354132054739921_6120722700567576576_n[1].jpg

Link to post
Share on other sites
  • 4 weeks later...

Happy new year to you all..

The Christmas New Year break allowed more work to be done on the boat, but not as much as I would have liked ..
More grinding /sanding of the internals, plus 16 2.5 inch holes were cut into the tabernackle.

From that I'm now suffering, as to do it, I was lying in the boat across three frames, arms above my head , squeezing a drill with holesaw into the small space. That isn't quite finished yet as they need sanding and the bottom pair of holes need squaring off a bit to give access to the mast step adjustment pins.

I was doing a good imitation of a snow man each of the two days of sanding. Full gloves, overalls, respirator, goggles and hat were worn!! the boat has been hoovered out , which took several cleanings of the filters the dust was that light it wasn't settling in the bin..

Also two days were spent sewing, the Kestral secondhand jib I bought, needed six inches cut off the luff at the bottom, going up to no removal at the peak. This was done some time ago and it was pinned up at the time.

The orginal jib was only seamed up to the first panel join, above that it was a bare cut edge, it didn't appear to be heat sealed, So I've done the same.
 The old corner reinforcing was unstitched off the piece that had been cut off, and sewn back on the jib.
Then instead of buying a hole punch and cringle insertion tools, I had some spare webbing so I've sewn on two loops .. Sewing through 5 layers of sailcloth and 4 of webbing where they meet at the bottom corner was difficult and definately required the use of an Awl first..
This sail is only temporary, and will be used for the sea trials inland waterway trials, and possibly the first season while the basic setting up is done.

By coincidence this sail was originally made by  a partnership that used to be about 100 miles away, one of those partners now lives about 5 miles from my house on the way to the sailing club. He may well get the commission for the new sails..

 

 

Link to post
Share on other sites
  • 3 weeks later...

So far not a lot has been acheived so far this January, part of this and the last week end was spent helping clear a widows house (friend of SWMBO) of unneeded stuff left by her husband.  This weekend it  included a 3 ft square safe, and several railway sleepers.. Then also there was a power cut in the area, while I was mid sand of the boat...

Anyway, over the last couple of weeks I've been calculating keel size and weight.. Excell helps a lot!!
it comes out as about 175KG, so when the power failed I went on the great lead hunt. I've been accumulating lead for many years knowing I'd need it. So it turns out I've got 116Kg of lead sheet and 119Kg of odd shapes, no doubt a few pounds will be wastage once I start molding. No I've never been on a church roof!!

My current plans are..

The maximum keel depth is 3ft, there is no question about that, as it is the boat I sail now, also of 3ft draft, touches bottom occasionally when approaching river banks before tacking and leaves a brown mud trail when we start sailing each season on Black Horse broad...

I've chosen a NACA0012 keel shape which just gives room for the keel bolts, while remaining fairly slim so as not to give too much drag..

The wooden keel will be assembled in slices, the top and bottom piece will shaped to a pattern, and all the pieces assembled onto the keel bolts (threaded rod). Then planed to the patterns.

 Once that is done it will be disassembled , the keel bolts mounted in the boat, then each keel section will be bolted and glued into place .. once that it all done a final sand will be needed.

So the lead lump is 6 inches high, above that is 2ft of keel, a span 30 inches wide at the top and 22 inches at the bottom. Through which 7, 1/2 inch keel boats will be fed. (Only 5 all the way through)

I'll shape a male mold from extruded polystyrene,  the shape is quite complicated, It will be a "L" Keel with a small  "beaver" tail.

I can see extreme difficulty in moving a 175KG keel in the space I have, so the male mold will then be sliced into 6 pieces, each to fit in a wooden tray.  Once the poly is waxed, it will be held down in a tray and plaster of paris poured around , and left to set. Once set and the poly removed, the tray will be baked to rid it of any moisture, ready for pouring.

Each of the slices will have the necessary holes drilled through for the keel bolts and each nut will have a hollow so the nut can be left in place. then each slice will be bolted and glued into place one at a time..

So the lead lump is 6 inches high, above that is 2ft of keel, a span 30 inches wide at the top and 22 inches at the bottom. Through which 7, 1/2 inch keel boats will be fed. (Only 5 all the way through)

Unless someone can come up with any better ideas?
 

 

Link to post
Share on other sites

Not much boat work this weekend will happen,  partly because tonight I shall be fully kilted up, giving the Burns address at the sailing clubs Burns night dinner. 

I've been going over and over the keel figures above because something didn't  ring true. 

Eventually I realised during one of the many redrawings of the keel / keel position I'd lost over 6 inches of span. So that has to be added to the figures above. I'll go back to the main drawings I did and start from the basics again. Being able to get 40kg more ballast inside the keel span means the beaver tail will probably disappear as more of the keel will be aerofoil shaped.  

I've also been looking at a trim tab on the keel,  it's an added complication , but should give better lift from the keel. However those that have used such things indicate they are difficult to set up due to all the variables of wind, tide, speed etc.. 

Link to post
Share on other sites

My very minimally informed guess is that the trouble with a trim tab would be that the relationship between the leading edge and the hull doesn't change. So effectively what it gives you is like trailing edge flaps on an aircraft. More lift and more drag, but not a major change in water going past the hull. Like a lot of these things, its probably not hard to get it working a bit, but very hard to get it working properly all the time. I also have a vision of tacking up the river Ant and and having to tack the keel as well...  On the other hand one can imagine dialing up a high and slow mode to get round a bend in the river, which we already do with rigs, but I'm not sure if the difference would be measureable. You need someone who knows a *lot* about low speed aerodynamics I suspect.

Link to post
Share on other sites
24 minutes ago, JimC said:

My very minimally informed guess is that the trouble with a trim tab would be that the relationship between the leading edge and the hull doesn't change. So effectively what it gives you is like trailing edge flaps on an aircraft. More lift and more drag, but not a major change in water going past the hull. Like a lot of these things, its probably not hard to get it working a bit, but very hard to get it working properly all the time. I also have a vision of tacking up the river Ant and and having to tack the keel as well...  On the other hand one can imagine dialing up a high and slow mode to get round a bend in the river, which we already do with rigs, but I'm not sure if the difference would be measureable. You need someone who knows a *lot* about low speed aerodynamics I suspect.

 Trim tabs on the aft end of the keel should give you more lift, hopefully more than the opposition,  so they can't sail over you. . When America's cup boats sailed not flew, many of them had trim tabs, but they generally had wide open spaces to sail in and many people to operate the boat , 

 Obviously you know that being able to go along a river without tacking for longer would be a huge gain.  But  one of the thoughts against it,  is complexity of use.  For the Ant,  I'm pretty sure you'd just end up locking it off in the central neutral position. Tacking in a river just 50ft wide is bad enough without more things to play with.. 

Just 127 days till this year's 3 Rivers Race applications are open on 3rr.uk.

 

I'm tempted to fit a trim tab anyway,  worst case scenario,  lock it off in neutral and seal up the hinge points at the back of the keel. 

Link to post
Share on other sites
1 hour ago, The Q said:

 Trim tabs on the aft end of the keel should give you more lift, hopefully more than the opposition,  so they can't sail over you.

Subject to correction by people who know more, I think its more complicated than that... My loose understanding is that if you're going in a straight line the lift from the keel exactly balances the lift from the sails. However there's also drag, not only from  the keel, but also from the hull, and in order to produce lift from the keel it will be sailing at an angle of attack, which we call leeway. So if we increase the lift on the keel then drag from the keel also increases - with lift comes drag - but because the lift needs to balance the sails we either keep the same track with less 'leeway' - in other words less drag from both hull and foil - or else sail higher so again the lift reduces back to equilibrium. Which is the better thing to do probably depends on more variables than I can possibly get my head round...

Link to post
Share on other sites

I was simplifying it,  you are complicating it,  :D, either way it should in theory give better performance,  unless you over do the trim and cause too much drag.. 

Link to post
Share on other sites
  • 3 weeks later...

No work done on the boat this weekend I was battening down the hatches for Storm Ciara, which peaked at 90MPH in the UK 70MPH locally.

On the way in the storm blew the waters away from the coast and caused this.. Normal tidal range 2 ft.....262434790_84DB1B6B-C070-4532-B4FD-BBA6C76B047D.jpeg.87105ce48fe85723060445e3fceaf0d01.jpg.248a46f35a9ed5f43d705eff47cb1a9e.jpg

Now it's on the way out the wind is blowing the sea down the North sea raising the water level and causing this..

1698193216_Capture.JPG.3e0cb33ad54d352276c5af922450e5fd1.jpg.1ef7e7bea124086756fe465d4af35550.jpg

Yep flood warnings over the entire Broads..

At least I live on a white bit surrounded by the orange...

This will cause a fish kill, as the salt water sweeps up the rivers killing the fresh water fish..

Link to post
Share on other sites
  • 2 weeks later...

The Marquee sides and roof have stayed off, with Ciara followed by Dennis, and almost a week later it's still blowing near 50mph out there..
I've also had a severe dose of the Lurgi so nothing has been done..

I did get bored and played with some sailing metrics calculators..

LOA              = 16ft
LWL              = 16ft
Beam            = 4ft
Displacement = 1100lbs
Ballast           = 385lbs
Sail Area        =130sqft

 Which gives.

SA/Disp          = 19.5    12 is regarded as low, >20 Generous,
Disp / LWL      = 122.1    <100 ultra light < 140 Light< 175 Medium
Max hull Speed= 5.4 kts
Motion            = 15.7
Ballast / disp   = 35        33 = average 40 = stiff
Capsize resistance = 1.5    < anything less than 2 is good..
 

 

Link to post
Share on other sites

Last weekend just 4 pieces of wood were cut for the keel , I've moved into the garage to do the work. In doing so I needed to get the electrics working... After much examination of the garage wiring... 40 year old electrics and not built to standard in the first place...So I made it safe enough for the the moment, but now the house of strong ladies has delivered various bits to do the job properly, which will be the first task tomorrow.

 

I've spent hours going, over and over the keel design.

The recommended keel area for my style of boat and keel keel is 7 to 10 percent of Sail area.

The drawings work out to be 7.1 %

Someone on the Boat design forum reverse engineered the keel Area verses the Sail area for shallow draft boats, to produce a formula by typing in the values of various known shallow draft Boats, That formula can be used to check what you've got or planned, typing in Blue Moon's dimensions it comes  out at IIRC 6.5 % of Sail area.. close enough for me..

I also reread an article from Eric Sponburg / David Vancanti https://www.ericwsponberg.com/wp-content/uploads/keel-and-rudder-design.pdf,

This on page 78 talks about a small "wedge " / Extension of the keel hydrofoil shape ,fitted to the front of the keel to assist in vortex reduction, it won't be a tank tested, computer designed "wedge" But I'll include one on Blue Moon's keel using the information provided. I've since done other research on this wedge and it appears there is an official name for it.. It's a Dillet, this is also fitted to many aircraft in a slightly different shape...

The Storms continue this weekend with the 3rd Named storm in February, this is the windiest month I can ever recall, gale force 8 forecast for later today..

 

Link to post
Share on other sites

This weekend the top and bottom Pieces of the wooden keel were cut / planed to hydrodynamic shape roughly.. That was done with power tools, next weekend they will be finally shaped using hand tools. A spokeshave will be employed on the dillet, which is looking good already. The Dillet being incorporated into one end of the top beam.

The Keel itself will no longer be solid wood but top and bottom horizontal beams with vertical supports, ply skinned and filled with polyurethane sheet.. Why Polyurethane sheet?. 'cos can I get it for free, as it's the cutouts from our packing department.. Oh and it wil be glassfibre covered like the rest of the boat..

The garage was a bit windy to start with as Storm Jorge was blowing under the corrugated roofing one end and out the other.. so I spent some time clearing back Ivy then filled the hollows with expanding foam. There is a bit more to be done, but it's a lot warmer in there and I can now justify turning on a fan heater, which will be needed when I start glueing and screwing things together..

I came across a secondhand book , How to design a boat By John Teale,  it cost a huge £2.85  delivered in good condition.. It turns out the main example used is that of a 20Ft open Keel boat , very like the sort of thing used here on the broads and that which I roughly based my ideas on... I've been working through the book using his formula and like the previous metrics shown a couple of post ago.. It's looking good.. I must have had a lot of luck designing this boat by what I  thought looked "Right"..

Link to post
Share on other sites

I know this is going to be an unpopular question, but wtf is this doing in dinghy anarchy, anything that two normal people can’t pick up is not a dinghy, and yes I have lifted and turned over Finns, FDs and 505s with only 2 people and no sky hooks or gantries. I don’t know where this should go as it obviously isn’t a sport boat either, maybe cruising anarchy?

Link to post
Share on other sites
15 hours ago, Major Tom said:

I know this is going to be an unpopular question, but wtf is this doing in dinghy anarchy, anything that two normal people can’t pick up is not a dinghy, and yes I have lifted and turned over Finns, FDs and 505s with only 2 people and no sky hooks or gantries. I don’t know where this should go as it obviously isn’t a sport boat either, maybe cruising anarchy?

Awww, don't be a hater. Yeah it's not a dinghy.

If there's somebody over in SA or CA that would be interested, they can find their way here. You could even be helpful. Or just say fuck it, this is anarchy

I care more about how it's going to float on it's lines than being in the wrong forum

FB- Doug

  • Like 1
Link to post
Share on other sites

The broads half deckers are more like ballasted dinghies than they are like anything with a lid. And have you tried picking up a Wayfarer with two people?

 

Link to post
Share on other sites

My summer club doesn't  have dinghy classes,  but does have many dinghies. 

We have the following classes

Allcomers C,   up to 12ft

Allcomers B, 12ft to 17.5ft, the class Blue Moon would be entering. 

Allcomers A1,  above 17.5 ft  Bermudan boats

Allcomers A2, Above 17.5ft gaff rigged boats. 

Broads cruisers, sailing boats with a cabin to the Broads Cruiser Class regulations, 

Sailing cruisers,  boats with a cabin that don't meet the BCC regulations. 

If there are sufficiently same class boats, then class races will be run,  normally,  the Yeoman,  Reedling,  Rebel,  and Yare and Bure one design classes are planned to do so. 

 

The others in Allcomers B may include,  

The classes previously mentioned,  plus international 2.4mR, lasers, Splash,   enterprises , fireball,  various things from RS, The NORFOLK dinghy, which has a 68lb galvanised steel centreboard....  brass buoyancy tanks and is clinker built, it's darned heavy. 

Although we don't have any, I'd love to see you turn over the 17ft Dublin bay Mermaid with its 130lb centreplate , and weighing 415kg  without sails or people..That's over Blue Moons 500kg with sails and me.  http://dublinbaymermaids.com/resources/

 

I put this here because I will be mostly sailing against  dinghies,  not sports boats, Blue Moon doesn't have a cabin,  not cruising, Blue moon will be racing.

  • Like 1
Link to post
Share on other sites

Some work was done on the Keel this weekend, limited in time by having to work on a Inkle loom for SWMBO  and more Ivy clearance from the garage roof.

Anyway the Dillet was planed to shape and sanded down, the trailing edges of the top and bottom beams were similarly treated.

Then the pieces cut so far were dry assembled  with just screws. This allowed me to cut to size, two more pieces, which will form the majority of the leading edge of the keel.

There will be a lot of planing needed  there, then two skins of ply will be required.. Once all has been dry assembled and checked for fit, then strip the lot and glue and screw..

Next week I'll have enough of it built for it to be worth while taking a picture or two..

Link to post
Share on other sites

Again limited work was carried out on the keel this weekend
The leading edge of the keel was screwed together, then I started Planeing, one side is down to it's rough shape the other about half planed, before the plane let go in a big way, the rotating drum is jammed.

 The plane is around 30 years old, so it's paid for itself, parts are not available for all of it, so a new one will be purchased this week.

I then started making bits for the inkle loom for SWMBO, looked at the keel skin, looked at the keel, looked at the keel skin, looked at the keel, looked at the keel skin, looked at the keel.. Something not right..
Held up skin to keel .. keel too big..

Yep I'd forgotton to take off the depth of the lead ballast weight, luckily with the keel only dry screwed together it was take all the screws out , cut the verticles to the correct length and reassemble. Recheck against the skins and... That's OK..

I was back working on the inkle loom when SWMBO looked in again..

Saturday night was the winter sailing clubs Prize giving and dinner, the dinner went very well.

For the first time in 18 years we didn't win any trophies as we didn't sail due to my sailing compatriots injuries. There is bad news with that, the missing piece of bone in his thigh is not healing over and the broken bone is not healing. He's likely to need further operations, to rejoin the broken bits. once that his healed his thigh bones will need stretching to get it back to the correct length. I can see us not sailing next winter as well..

The review of the years events showed the club doing well , with the club itself winning two inter-club trophies, and the dinghy fleet being much up in numbers..

https://www.sfsc.co.uk/pages/

https://www.facebook.com/SnowflakesSailingClub

https://www.facebook.com/hashtag/probablythebestsailingclubintheworld?__cft__[0]=AZU8iMwIqO_zB8dl0lU3-5YFV_Osz9eUK7ZsxPwQdIQA6TKju9gLsV3zIwVBzW_NqhoeEAGXxEvm0PLDC7fBHXX_pbCq7jW1CD03YYUdUjO9KD5eIDMU0BS6a8XafE3zHNakGQ7sh9_qGdEdzb5zWgMsgwAhlww0ZKwgWqLvWOiDjg&amp;__tn__=*NK-R

 

 

Link to post
Share on other sites

Not many on here will have been going, But the Horning Boat Show 2nd May 2020 has been cancelled / postponed till 1st May 2021.. 

Coronavirus strikes again..

Link to post
Share on other sites

Not too much work was done this weekend , the nose of the keel was planed with the new planer  very good it is too, if a little heaver than the previous one.
Then the keel was glued and screwed together, so because that was setting no futher boat work was done..
Hopefully next week there will be less wind so I can get the marques covers back up which will then enable me to work on the rest of the boat, when not working on the keel...

Further Ivy removal from the garage was done, that meant the remains of facia came off..

Messers Bodgit and Run Garage builders extraordinaire struck again.. The wood above the window is made of no less than 7 pieces of wood. I'm picking up a new concrete lintle on the way home today, plastic facia boards and a few other bits and pieces. I want the stuff in, even if not used this next weekend, in case we get locked down and I can't go to work.

 I have by chance, a double glazed upvc window we cleared from a widows garage, it's just a little smaller than the current garage window that has a rotten wooden frame. So when the lintle is put in, up higher to replace the layers of wood, the new window wil be mounted tight underneath it, the space below bricked in..

Messers Bodgit and co , also Bu***erd up the roof, I noticed a line of light from the underside that shouldn't be there ( now revealed as I had cleaned that part of the roof). On inspection I dicovered this 4 ft piece of Asbestos corrugated roof had been cracked on installation..
 How do I know it was on installation? because all the others have their bolts in pairs.. This one, the bolt one end was offset onto the next intact ridge.. A repair has been done with a length of flashing tape to keep the water out.

Link to post
Share on other sites
  • 2 weeks later...
On 3/23/2020 at 11:26 AM, Steam Flyer said:

You know it's taken a long time, when you have to build a new building to continue building your boat in.........

:rolleyes:

FB- Doug

To true , I've been spending more time on that than the boat. 

The current state of the keel stub is , that both skins are on the keel, the core is filled with foam, the keel bolts are fitted and fixed in place. 

I've now to tidy up the nose of the keel,  smoothing in the skin to the nose.  Then carve a foam male mould for the lead lump, dry fitting that to the bottom of the stub, to check it fits,  before creating the female mould. 

As the temperature is warming up I may be able to start working on the hull itself this week. 

Time to wander outside and remove the 14 clamps holding 2ft Of skin onto the nose the glue should have set by now. . 

 

  • Like 1
Link to post
Share on other sites
  • 3 weeks later...

Progress has been slow due to other things, all the Ivy has gone from the garage roof.  Unfortunately that also revealed the ancient lean to bike shed of corrugated iron is terminally sick. So a new shed has been ordered to replace it.

  The fibreglass skin moulding for the keel bulb has been made, it's only a couple of inches wider than the keel. At the moment it's 4 layers of glass on the bottom and bow,  2 or 3 on the stern and sides.  

The moulding  was then measured for the bolt holes,  on measuring for the second set,  it didn't look right... 

I'd forgotten to allow for the slope of the nose..  Remeasured,  marked up placed on keel without  drilling,  still 1/4 inch out.

  Rubbed off markings, measured again placed on keel looked OK,  went for Muggacoffee. 

Remeasured placed on keel again,  still OK.  Sacrificed a new wood drill bit as they have a point to stop wandering. Holes drilled.... Keel moulding placed on keel,  bolt holes matched, slid down onto keel.  Moulding matched keel shape and position...  Much relieved.. 

At the moment I'm cutting sheets of lead to shape and dry laying them inside.  Once I've made them all, then I'll bond them in. I had hoped to cast the lead for better density,  but the problems are not worth the effort for me. 

 

Link to post
Share on other sites
Link to post
Share on other sites
  • 3 weeks later...

After trying several attempts at getting the required lead density using layers of lead it just didn't work.  So I had to spend some money to buy a lead melting pot,  this look a couple of weeks to arrive. After prying out the previous attempt,  I've now cast about half of the keel.  

The lean to bike shed was helped to fall down,  and has been replaced by a modified tin shed kit. Today I will be continuing to install  the floor.  While doing that the lead melting pot will be in use,  I did about 20kg yesterday while doing the first half of the floor.   When the shed is done,  my spare wood supplies will be moved from the garage to the shed,  this will give me room to assemble lead ballast to keel.                      Picture below of new shed.

On the Norfolk Broads then sailing clubs organise their annual regatta weeks  so in general only the weekends might conflict. The club the week before us (NBYC) the has now cancelled their regatta, the last week in July,  due to the virus . It seems premature to me to cancel this early as restrictions are being eased.  I would hope my club will wait till at least the beginning of July for a decision.

As it is, the company I work for has introduced a restriction on taking holiday that at least half must be taken by the first of September. So I'll book regatta week anyway and if it's off, spend a week boat rebuilding. 

IMG_20200520_131350.jpg

Link to post
Share on other sites
  • 3 weeks later...

Well, I'm back at work having been recalled last week. a huge backlog of equipment for me to calibrate, I'm sat here waiting for the machine to finish it's current 33 minute automatic run. (of 14 man hours work on this equipment)

So progress will return to it's glacial speed.

Since the last missive all the spare lead I had, has been melted and poured. So Saturday I started breaking Batteries, picking the two largest first, 24 cells, each had 19 plates in them, each of the 456 plates had 2 layers of mesh cloth on them, every other one was in a plastic bag. 

Each cell, when removed, was dumped in to a bucket of water / bicarbonate of soda. when the bubbling ceased , each cell was stripped, cutting off two thick lead joiners, then removing the bags and as much of the cloth mesh as I could. As each was stripped they went into a fresh bucket of bicarb and water. 

They are all now stacked to dry, liquid lead and water are an explosive mix...

The lead joiners were dried and melted so two pots of lead were poured. 

Next week the exciting task of cutting /breaking the plates into pot sized pieces and more melting.

Link to post
Share on other sites
  • 3 weeks later...

Well the lead recovered from the batteries wasn't worth the effort much to much slag not enough lead. They Are however worth 50p a kg at a scrap yard, I have about 10 batteries left, I'll take them in sometime. That will more than cover the £29 I spent of buying 10Kg of scrap lead delivered, which turned out to be A4 sheets of lead flashing. now melted and installed. the ballast now weighs 152 KG with the target being 150Kg, but I still have to drill the keel bolt holes..

I've also scraped the deck, with just a little bit of stubborn stuff left to remove, I decided I'd better get a move on stripping the decks, if I want to get several coats of varnish on this summer.

with the reduction of our distancing regulations  this side of the pond from 2 metres to 1 metre to 2 if you've got room, there is a chance that sailing /racing may recommence soon, which would be very welcome