• Announcements

    • UnderDawg

      A Few Simple Rules   05/22/2017

      Sailing Anarchy is a very lightly moderated site. This is by design, to afford a more free atmosphere for discussion. There are plenty of sailing forums you can go to where swearing isn't allowed, confrontation is squelched and, and you can have a moderator finger-wag at you for your attitude. SA tries to avoid that and allow for more adult behavior without moderators editing your posts and whacking knuckles with rulers. We don't have a long list of published "thou shalt nots" either, and this is by design. Too many absolute rules paints us into too many corners. So check the Terms of Service - there IS language there about certain types of behavior that is not permitted. We interpret that lightly and permit a lot of latitude, but we DO reserve the right to take action when something is too extreme to tolerate (too racist, graphic, violent, misogynistic, etc.). Yes, that is subjective, but it allows us discretion. Avoiding a laundry list of rules allows for freedom; don't abuse it. However there ARE a few basic rules that will earn you a suspension, and apparently a brief refresher is in order. 1) Allegations of pedophilia - there is no tolerance for this. So if you make allegations, jokes, innuendo or suggestions about child molestation, child pornography, abuse or inappropriate behavior with minors etc. about someone on this board you will get a time out. This is pretty much automatic; this behavior can have real world effect and is not acceptable. Obviously the subject is not banned when discussion of it is apropos, e.g. talking about an item in the news for instance. But allegations or references directed at or about another poster is verboten. 2) Outing people - providing real world identifiable information about users on the forums who prefer to remain anonymous. Yes, some of us post with our real names - not a problem to use them. However many do NOT, and if you find out someone's name keep it to yourself, first or last. This also goes for other identifying information too - employer information etc. You don't need too many pieces of data to figure out who someone really is these days. Depending on severity you might get anything from a scolding to a suspension - so don't do it. I know it can be confusing sometimes for newcomers, as SA has been around almost twenty years and there are some people that throw their real names around and their current Display Name may not match the name they have out in the public. But if in doubt, you don't want to accidentally out some one so use caution, even if it's a personal friend of yours in real life. 3) Posting While Suspended - If you've earned a timeout (these are fairly rare and hard to get), please observe the suspension. If you create a new account (a "Sock Puppet") and return to the forums to post with it before your suspension is up you WILL get more time added to your original suspension and lose your Socks. This behavior may result a permanent ban, since it shows you have zero respect for the few rules we have and the moderating team that is tasked with supporting them. Check the Terms of Service you agreed to; they apply to the individual agreeing, not the account you created, so don't try to Sea Lawyer us if you get caught. Just don't do it. Those are the three that will almost certainly get you into some trouble. IF YOU SEE SOMEONE DO ONE OF THESE THINGS, please do the following: Refrain from quoting the offending text, it makes the thread cleanup a pain in the rear Press the Report button; it is by far the best way to notify Admins as we will get e-mails. Calling out for Admins in the middle of threads, sending us PM's, etc. - there is no guarantee we will get those in a timely fashion. There are multiple Moderators in multiple time zones around the world, and anyone one of us can handle the Report and all of us will be notified about it. But if you PM one Mod directly and he's off line, the problem will get dealt with much more slowly. Other behaviors that you might want to think twice before doing include: Intentionally disrupting threads and discussions repeatedly. Off topic/content free trolling in threads to disrupt dialog Stalking users around the forums with the intent to disrupt content and discussion Repeated posting of overly graphic or scatological porn content. There are plenty web sites for you to get your freak on, don't do it here. And a brief note to Newbies... No, we will not ban people or censor them for dropping F-bombs on you, using foul language, etc. so please don't report it when one of our members gives you a greeting you may find shocking. We do our best not to censor content here and playing swearword police is not in our job descriptions. Sailing Anarchy is more like a bar than a classroom, so handle it like you would meeting someone a little coarse - don't look for the teacher. Thanks.
Sign in to follow this  
Followers 0
Connor.kainalu

Chines in yacht design

53 posts in this topic

In recent years the stylised look of the modern racing monohull ha come to include a plum or reverse bow, a square top mainsail, fractional jib, and vertical chines in the aft third. Are vertical chines really helpful speedwise? I know that corners are really bad on a yacht, but does the nature of the angle being parallel to the flow cause any difference? And has anyone experimented with chines angled inboard? And does the sharpness matter?

Share this post


Link to post
Share on other sites

You can count reverse bows on monohulls on one hand, so it can't be called a trend. I don't even know what a vertical chine is, perhaps you'll post a picture.  if such a thing exists, it's rare enough not to be a trend. I guess the designers would have the best answer for their purpose. The race course is the best measure of their effectiveness.

Share this post


Link to post
Share on other sites

I think he means vertical topsides above the chine. 

Share this post


Link to post
Share on other sites

I would think that having the topsides come up vertically from the chine would help to reduce wetted surface.  Any angle to the topsides at a chine would tend to increase wetted surface.  Angling the topsides outwards would also add weight, not only for the additional amount of topsides (hull) but also for the deck that would have to be extended to cover the now wider boat.  Angling the topsides inwards might reduce the deck width and weight, but would still add to the hull weight (due to the extended sides of the hull) and the wetted surface. Angling the topsides inward might also lead to reduced buoyancy as the hull submerged more... not necessarily what you want if you're surfing down a wave and might get pooped.  

Share this post


Link to post
Share on other sites

My guess is this is another rating aberration. Beam generally cost you in rating, so just wack it off 'here' and pretend it's narrower. Sharp angles traveling through fluids are rarely fast. 

Plumb bow and square top main there is some theoretical basis for, confirmed by experience. They are faster, and are also penalized. 

Share this post


Link to post
Share on other sites

Square top is an attempt to get an elliptical lift distribution spanwise. So that is based on actual efficiency.
Plumb bows on "box rating" boats are merely to maximise wetted length. No superior to some rake except for a small weight saving.
Chines are never helpful at sailboat speeds. Except for skiffs and other truly planing boats. This now includes some keelboats but none of the production ones.

Fads spread like wildfire.

Share this post


Link to post
Share on other sites

The chines are helpful with a Volvo 70 -limited by beam and water ballast. The chine allows you to get more water outboard but keep the waterline beam less. And they are at planing speed so probably shed water keeping wetted surface low when reaching. So sharp chines are good.

Share this post


Link to post
Share on other sites

IF BOATS WERE MEANT TO HAVE CHINES, FISH WOULD HAVE SQUARE FINS!

Share this post


Link to post
Share on other sites

Tell that to John Spencer.  Infidel / Ragtime, Whispers of Wellywood and a whole generation of his chined boats were awesome performers.

Share this post


Link to post
Share on other sites

Plumb bows I can live with reverse bows just don t seem right square top mains yea more sail I'm in and Chines make me think of homebuilt fireballs or steel cruising boats and I like to go fast I just believe you should look good while doing it and while I'm sharing my preferences for style on the water the modern cruise ships look like ugly wedding cakes or lost apartment blocks give me the old Brittania QE or even the QE 2 even the titanic looked good even if it couldn't turn

Share this post


Link to post
Share on other sites

Chines often allow he designer to flatten the buttocks aft and that's good for high speed sailing where you want a flat run.

On production cruising type boats chines add volume aft where berth flats commonly are. They can also add some form stability.

But in many cases they are like spoilers of Toyota sedans.

Share this post


Link to post
Share on other sites

Chined fish? Who knew.

Jk407Oz.png

Share this post


Link to post
Share on other sites

The chines on Ragtime had more to do with plywood than performance. 

Share this post


Link to post
Share on other sites
2 minutes ago, DDW said:

The chines on Ragtime had more to do with plywood than performance. 

That maybe but the chines didn't seem to hinder the performance any!

Share this post


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

Plumb bows I can live with reverse bows just don t seem right square top mains yea more sail I'm in and Chines make me think of homebuilt fireballs or steel cruising boats and I like to go fast I just believe you should look good while doing it and while I'm sharing my preferences for style on the water the modern cruise ships look like ugly wedding cakes or lost apartment blocks give me the old Brittania QE or even the QE 2 even the titanic looked good even if it couldn't turn

You know you can buy punctuation here, it's not that expensive.

Share this post


Link to post
Share on other sites

Hmmm.....there is some fad with this with everybody and there dog doing chines and all the Bunter type of builders so it's all bull shit. How boat a real boat hmmm? My friend Mr. Bieker might have something to say about that.

 

IMG_0002.jpg

IMGP6515 (800x536).jpg

Share this post


Link to post
Share on other sites

And a little boat called Dark Star too. We had a killer start at Straits that year. 

DKSTR.2.sml.jpg

d.star.4.JPG

Share this post


Link to post
Share on other sites

I love that Longboard, have for a few years. Hope you are at SOAR.

Share this post


Link to post
Share on other sites
1 hour ago, Norse Horse said:

I love that Longboard, have for a few years. Hope you are at SOAR.

Longboard and Dark Star are 1/2 on the Hein Bank/Swiftsure race. It helps that there was a lot of talent on both boats but it tells you something I guess. Love the SOAR regatta. Might have been at very first one in '80. If not shorty afterwards and competed for many years. As a matter fact my crew was actually thrown out the Cheftain beer parlor. And I don't have to tell that that takes some doing. My crew did. Now the regatta is at high cruising time so haven't come back for sometime. Too bad but? It's like the Gorge in saltwater.

 

 

Share this post


Link to post
Share on other sites
21 hours ago, Last Post said:

Tell that to John Spencer.  Infidel / Ragtime, Whispers of Wellywood and a whole generation of his chined boats were awesome performers.

plywood does that to a design.

Share this post


Link to post
Share on other sites
Just now, duncan (the other one) said:

plywood does that to a design.

Plywood, the Carbon Fibre of its age !

Interesting to note that John Spencers few round bilge designs were largely unsuccessful performers

Share this post


Link to post
Share on other sites
57 minutes ago, Last Post said:

Plywood, the Carbon Fibre of its age !

Interesting to note that John Spencers few round bilge designs were largely unsuccessful performers

Huh. Still love the Thunderbird logo on Ragtime on the main in the '70's. T-birds and still be reckoned with in racing PHRF.

Share this post


Link to post
Share on other sites

Chines are fast, they give you extra righting moment at low angles. RM is power.  They also stiffen the hull. 

Adding chines to composite hulls has been going on for a while now. 

Share this post


Link to post
Share on other sites

So if a Destroyer, an FPB 64, an Open 60/Volvo 70 and a Bieker Riptide 55 all have plum bows, is it nothing more than maxing out waterline or are their other characteristics such as wave piercing ability that makes  the shape more than just a trickle down trend for post '08 Clorox bottle cruisers?

Share this post


Link to post
Share on other sites
2 hours ago, Panoramix said:

Chines are fast, they give you extra righting moment at low angles. RM is power.  They also stiffen the hull. 

Adding chines to composite hulls has been going on for a while now. 

They also tend to create discontinuities in the waterline plane and sectional area curves which usually leads to increased wave drag.

Share this post


Link to post
Share on other sites
53 minutes ago, 12 metre said:

They also tend to create discontinuities in the waterline plane and sectional area curves which usually leads to increased wave drag.

Yes, I think that getting it right is quite hard. During the plywood era good designers were producing much better boats. 

Share this post


Link to post
Share on other sites

Chined boats seem to have more form stability, especially as regards to rolling. Very noticeable if you've ever been on a Rothbilt unchined skiff vs. a Carolina skiff, for example. They are very popular on midsize power boats- you can see a fair amount of hard chined lobster and tuna boats. Mr. Perry is right. Only downside is that they seem to slam more going through waves.

 

It's questionable how important they are to a boat which gets the majority of its righting moment from ballast and doesn't plane, but for bigger racing boats that go fast and get a lot of RM from beam I could see the need.

Share this post


Link to post
Share on other sites

Just because some fast boats have chines, doesn't mean that chines made them fast. The question for Mr. Beiker (or whoever) is, "design a boat with no rules except to be as fast as possible on all points. Will that boat have chines?"

I think it more likely that chines might make a boat faster that is constrained by rules, cost, crew weight, accommodation, styling, marketing, or other. 

The primary reason we see them on cruiser racers is they contribute to sales. History has proven that the yacht buying masses are slavish to style, and style is set by elite racers even though the solutions applied there may be irrelevant in other contexts. 

Share this post


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

Just because some fast boats have chines, doesn't mean that chines made them fast. The question for Mr. Beiker (or whoever) is, "design a boat with no rules except to be as fast as possible on all points. Will that boat have chines?"

I think it more likely that chines might make a boat faster that is constrained by rules, cost, crew weight, accommodation, styling, marketing, or other. 

The primary reason we see them on cruiser racers is they contribute to sales. History has proven that the yacht buying masses are slavish to style, and style is set by elite racers even though the solutions applied there may be irrelevant in other contexts. 

Something like the Bieker Riptide 55 was designed only to the owner's rule, to go fast. It had chines. Designed some 15 or so years ago (maybe more). It would be interesting to know what some of the other 'constraints' are that led to the hull shape (it had water ballast), or if their are further 'performance' considerations that led to the hull shape. (It also had that trendy plum bow thingy).

That said, your point is well taken, that the trickle down to cruisers may be irrelevant in terms of performance gain.

Share this post


Link to post
Share on other sites

Bieker cut his teeth in the I-14 class and you can see some of that heritage in the chined hull form of the Riptide series. There is a speed at which chines get some water release and reduce wetted surface but as boats get bigger that speed goes up. Case in point compare the Laser with the Force Five hull form.

Share this post


Link to post
Share on other sites
2 hours ago, DDW said:

Just because some fast boats have chines, doesn't mean that chines made them fast. The question for Mr. Beiker (or whoever) is, "design a boat with no rules except to be as fast as possible on all points. Will that boat have chines?"

I think it more likely that chines might make a boat faster that is constrained by rules, cost, crew weight, accommodation, styling, marketing, or other. 

The primary reason we see them on cruiser racers is they contribute to sales. History has proven that the yacht buying masses are slavish to style, and style is set by elite racers even though the solutions applied there may be irrelevant in other contexts. 

he did that already and you can see the result in the lagoon at Oracle HQ....

 

So, you need to add at least one rule - monohull....  

Share this post


Link to post
Share on other sites

Need to differentiate between underwater and above water chines.

Hard bilges accomplish the same things as underwater chines although to a slightly lesser degree, but without the additional wave drag issues.  The main advantage of underwater chines is to facilitate plywood construction.

Above water chines can increase heeled RM by allowing the Centre of Buoyancy to shift more outboard.  But with the heel comes additional wetted surface and a greater degree of immersed assymetry.  They can help promote planing - mainly by flattening out the aft buttock lines.

In summary, there are few absolutes in sailboat design - almost everything involves trade offs in one form or another.   In my view, this is the beauty of sailboat design.

 

Share this post


Link to post
Share on other sites

Chines are for sailing on and reduce wetted surface.

4_efcc2c9711.jpeg

Share this post


Link to post
Share on other sites

Then there is the Riptide 50 "Strum" (had the pleasure to race on that too) with no chine. 

Strum2.jpg

Strum3.jpg

Share this post


Link to post
Share on other sites

Chines predate plywood...Star, Fish, Seabird Yawl, Snipe. Simpler and easier construction...cheaper boat. If the chines are immersed when boat is upright, they have no effect on stability. Chines are faster on planing boats, when planing. Chines on FG cruising boats are a styling fad.

Share this post


Link to post
Share on other sites

And this is a little off topic but I thought I'd share this with the rest of class.

Paul the always the innovator without getting stupid about it as this the rudder/shaft arrangement I shot yesterday on Longboard:

 

20170618_142321 (600x800).jpg

Share this post


Link to post
Share on other sites

Chines can make for simpler construction if the surfaces can be simplified into single curvature or planar.  If properly designed, chines can allow for clean release of the flow below the chine at higher/planing speeds.  But, on sailboats operating at multiple heel angles, the designer needs to be very careful of the shape of the chine, otherwise it will be more drag if the chine dips below the water surface.  

As always, trade offs...

Share this post


Link to post
Share on other sites

Nice for a racing boat. Has the makings of a maintainence nightmare. A saildrive is pretty low drag, much cheaper, and very low maintainence. Windward Passage had a retractable prop when launched. IDK if they retained it over the years....likely not.

Share this post


Link to post
Share on other sites
3 hours ago, 12 metre said:

Above water chines can increase heeled RM by allowing the Centre of Buoyancy to shift more outboard.

 

That is only true if there is a beam constraint. I hard bilge turn, outside of where the chine would have been, has more righting moment still. If the designed max heal places the chine right at the waterline, then some laminate might be saved. But then the chine is going to have to have a very funny shape (reverse sheer with a wiggle at the bow wave?).

In the racing crowd, either there is a beam constraint and the chine allows the hull to act like it is wider that it would otherwise (which I think is your point), or the usage profile has a very high percentage of downwind planing, or the designer/owner thought it looked cool. 

Share this post


Link to post
Share on other sites

I heard a rumour about the rs aero's chines "digging in and preventing leeway" any truth in that?

Share this post


Link to post
Share on other sites
22 minutes ago, Connor.kainalu said:

I heard a rumour about the rs aero's chines "digging in and preventing leeway" any truth in that?

Possibly - to a small degree.  But the term "digging in"  sounds a lot like increasing drag and marketing hype to me.

Concept was used to decent effect many years ago on the Hobie 14 - but much more efficiently - and was the only element for side force (other than of course the rudder(s).

H14.jpg

Share this post


Link to post
Share on other sites
1 hour ago, Connor.kainalu said:

I heard a rumour about the rs aero's chines "digging in and preventing leeway" any truth in that?

 

Carve a ww kayak like a Necky Jive in and out of an eddy and you get an appreciation for how much power a chine can have.

Now try the same eddy moves in an Eskimo Topolino or old slalom boat with no chines. Make SURE you paddle is in the water bracing.;)

 

 

Share this post


Link to post
Share on other sites
2 hours ago, Connor.kainalu said:

I heard a rumour about the rs aero's chines "digging in and preventing leeway" any truth in that?

'Preventing' is a gross exaggeration. A slight reduction of leeway is more accurate, but it's a very inefficient way of doing so.

Share this post


Link to post
Share on other sites
12 minutes ago, RKoch said:

'Preventing' is a gross exaggeration. A slight reduction of leeway is more accurate, but it's a very inefficient way of doing so.

Situation: international 14: sometimes, if the reach mark is tight or we've over stood with the kite up, we'll "ride the chine" in a slow, controlled fashion. If you bleed off speed, by heeling, oversheeting the kite a bit and otherwise going slow you can get to a mark faster than going fast, dousing, and re-housting after the gybe.

That has fuck-all to do with cruisers. I like chines on cruisers. Fat ass, lots of volume inside.

Share this post


Link to post
Share on other sites
9 hours ago, Maxx Baqustae said:

Then there is the Riptide 50 "Strum" (had the pleasure to race on that too) with no chine. 

Strum2.jpg

Strum3.jpg

But she has never really shown true legs racing. Rates faster than a Tp52, but I don't think she could beat any of them.  Very roundshaped design vs the 35.  

Share this post


Link to post
Share on other sites
16 minutes ago, Irish River said:

But she has never really shown true legs racing. Rates faster than a Tp52, but I don't think she could beat any of them.  Very roundshaped design vs the 35.  

I hear you Irish but I don’t think it was supposed a full on world beater. I believe the agenda/design folio was not for that. I really don't know. I was just along for a kewl sailboat ride. 

Share this post


Link to post
Share on other sites

 

'Ride the Chine' 

and

'Digging in to prevent leeway.'

both make sense depending on what point of sail.

Share this post


Link to post
Share on other sites
On 2017-06-19 at 9:39 AM, fufkin said:

Something like the Bieker Riptide 55 was designed only to the owner's rule, to go fast. It had chines. Designed some 15 or so years ago (maybe more). It would be interesting to know what some of the other 'constraints' are that led to the hull shape (it had water ballast), or if their are further 'performance' considerations that led to the hull shape. (It also had that trendy plum bow thingy).

That said, your point is well taken, that the trickle down to cruisers may be irrelevant in terms of performance gain.

On 2017-06-19 at 1:23 PM, RKoch said:

Nice for a racing boat. Has the makings of a maintainence nightmare. A saildrive is pretty low drag, much cheaper, and very low maintainence. Windward Passage had a retractable prop when launched. IDK if they retained it over the years....likely not.

Virtually no maintenance at all - service universal joint every 3 years.  The retracting drive unit is so simple and under power pushes Longboard over 8 knots into any seaway - we have to throttle back as prop will launch boat over waves - unlike a saildrive.  When retracted - no turbulence or vibrations when planing downwind.  It's a beautiful piece of Bieker engineering. 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0