Hull shape vs chop

I have a less than rudimentary understanding of hull shapes - planing, V hull, transitional, displacement...  At my club the fleets are Laser and Sunfish.  An old-timer at the club suggested these are the best for our location.   I'm curious to get other feedback.  There are other clubs in the area that have thistles and some other things.   We have some typical chop in Galveston Bay - 6 inches to a foot I guess on a typical day with 1 to 2 foot rollers on occasion - lots of channel traffic close to the club.  Lots of bobbing up and down to get the boat off the ramp, past the piers and into the bay.  Breeze is typically pushing back to the club, so Lee shore if I understand the terminology right.  I'm new to this, so my experiences are limited.  

Looking at dinghy hull shapes, is one better suited to this than another?  I'm looking at and comparing pictures of different boats: VX-EVO with its very vertical wave piercing front end that transitions to harder chine as it moves aft, next the Melges 14 with a similar bow but maybe slightly less pronounced (plus it has the wings like a raider instead of the aft chine from what I can tell), Megabyte (shaped more like a Laser but with more hull depth and slightly more vertical pointy end), then Aero with angular chines and less vertical prow, Laser, and then Sunfish with low hull depth and damn near vertical sidewalls.  Curious about the soft curves vs chines and planing ability and what kind of combination you want with chop.  I suppose you want different characteristics for cross wind/wave and downwind sailing.  So, the hull shape is a marriage of features?  Ultimately is there an ideal hull shape for these conditions?  If so, does any of the boats listed above (or some other) embody those characteristics the best?

When people talk about planing upwind (and debates about when or if that's possible with certain boats), what hull characteristics are helpful for that in chop?  What shapes are the best for speed?  What shape is the best compromise of speed, stability, good handling characteristics?  I'm sure these are all loaded questions, but hopefully some discussion will help my understanding.

 
Probably more important to adjust your technique and rig set up to deal with the chop than overthink the hull shape, though would suggest that a heavy boat might be better at punching through the waves whereas a light boat might get knocked about.  Fuller sails, sailing free, plate up a bit might help.

 
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fastyacht

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Fav bit is "sunfish and laser best" weel ya, thems the only twp singlhanders in large numberx. Nothing sim aboit them lolz

 

TeamFugu

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Narrow beam will go through chop faster. I know that between the Muston Performance Skiff and the Swift Solo, the narrower Musto with it's hard chines frees the water faster than the curved wings of the Swift where the water tends to go up the hull all the way to the gunwales. A Laser will just be faster than a Sunfish for many more reasons than just hull shape. I'm sure the choice of other boats at other clubs has more to do with preferences of craft than speed through the waves. Likes tend to attract like. What makes an even bigger difference is the person with the wiggly thing in his hand. Steer to the waves. You don't want the boat bouncing and especially banging on the waves. I've been in lead mines where one person at the helm was doing 4.5 kts slamming into the waves. Same boat and a different driver, smooth sailing and 7.5 kts.

Chase the flat spots and avoid the big ones. About every seventh wave is the largest of the set. Even if you have to ease out a bit or pinch now and then, stay in the flat water as much as you can.

 

Steam Flyer

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If you want to say that each type of boat is a marriage of features, then you're 1- assuming a high level of proficiency in boat design and 2- a far more harmonious and complementary set of features than most boats have.

I'm not sure your questions have ever been addressed scientifically. But yeah, hull shape affects how it goes thru waves, both ways. So does the fore/aft weight distribution in a given specific hull.

... I've been in lead mines where one person at the helm was doing 4.5 kts slamming into the waves. Same boat and a different driver, smooth sailing and 7.5 kts.  ...
Just the timing of the motion of the helm will make a big difference; a helmsperson who can anticipate and "meet" the boat's motion will give the perception that waves are smaller & smoother, although the difference in speed might not be as much from just that one thing.

Hiking dinghies are not going to plane to windward. Well, a very few can, but those ones don't have classes here in the USA. And they won't do it in the face of much chop, anyway.

Sail a bunch of different boats, see which ones you like. Every boat is a compromise, how much you like (or dislike) them is subjective.

FB- Doug

 

RedTuna

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Breeze is typically pushing back to the club, so Lee shore if I understand the terminology right. 

When people talk about planing upwind (and debates about when or if that's possible with certain boats), what hull characteristics are helpful for that in chop?  What shapes are the best for speed?  What shape is the best compromise of speed, stability, good handling characteristics?  I'm sure these are all loaded questions, but hopefully some discussion will help my understanding.
Terminology is correct. Pic below is facing generally SE into the prevailing winds.  I haven't been there in some 25 years but I remember we had to walk our Hobie through the shallows past the breakwater.  Great fun once on the bay.  Consider a multihull, given your questions above.

seabrook sc.jpg

 

JulianB

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Back in the 70's - 80's we did a series of full size tow-tests using NS14 hulls, and some of that is in Dad's books.

The vee fwd make a significant difference to hull drag when going up wind at displacment speeds and we use that on the 29er and 49er plus various Sportsboats and the SKUD.

If you want I can dig out some notes??  

Chines aft up wind are almost irelevant upwain, they come into there own downhill at planning speeds.

                   jB

 
Consider a multihull, given your questions above
I'm planning to get a Wave or Weta for family fun (been actively combing ads - not much close by), race Lasers or Sunfish with the club boats, but just generally curious what the different bow shapes in particular do for the monohulls.  The VX Evo or Melges 14 sound attractive to me over a Laser for recreational solo monohull sailing, but the budget (and deep cockpit) on the Megabyte sounds better until you throw the Great Red Shark's mast problems in the mix.  Just generally trying to get an idea if the Melges or VX Evo bow would cut chop or waves better than say the Laser for instance. 

 
Too many questions but here are two simple answers: If you plan to race, then buy what everyone else races. If you plan to casually day sail for sheer pleasure, then buy the boat YOU like. Happy Sailing!

 
Too many questions but here are two simple answers: If you plan to race, then buy what everyone else races. If you plan to casually day sail for sheer pleasure, then buy the boat YOU like. Happy Sailing!
I plan to do both.  I'm an Mech Engr stress analyst by day and I tend to overanalyze everything, but am interested and comfortable getting into the details.  In the end, that's overthinking it for my needs and experience level, but just curious about the design process and how they arrive at the choices they do.

 
Hot and Soggy, If you have actually settled on a Wave or a Weta ( not just thinking along those lines ) I may be able to help. I have owned both and sailed them extensively, both in a racing environment and for pleasure. They are both excellent but also quite different. If you like, let me know how to contact you and I promise I'll talk your ear off. Maybe I can help you in the decision. 

 

fastyacht

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All that fascinating stuff that JB and Simonn and others wrote about more recent dinghies notwithstanding, the "science" of sailboat dinghy design is rather different historically.

Sunfish: Two guys from Waterbury who sometimes went to the beach at Madison CT got this idea to build a minimal sailboat. That was the sailfish. That was too minimal. So they made the sunfish. That knocked it out of the park. Hyrodynamics? HA! Aerodynamics? DOUBLE HA!

Something fun? Simple? Easy to rig? Decent sailing characteristics? Seat of your pants design? You betcha. Did they have a sense of proportion? Grace? Clever mechanical stuff? YES! "Struck a chord."

Laser: Former sailing / journalist turned Olympic sailor and 14 sailor gets this crazy idea with his friend Ian Bruce who knows how to build boats. More to it of course but basically, "hey, what if?" make simple beach boat loosely based on experience with sailing international 14s and Finns. The rest is history...

Hey, I get PAID to design little boats. (I get paid a lot more to design the really big ones. Thank you, big oil and big Ag). Hydrodynamics is important but in a relative sort of way. Everything is always a trade off. What are you trying to achieve? The most scientific little boat I ever designed (did tow tests) was 19 feet involved 2 hulls and I was not interested in resistance.

There is a long history of amateur yacht design. I have a book on the shelf about hydrofoil sailboat design that is many decades old. Yes, there was hydrofoil sailing in the`1950s. "Amateur Yacht Research Society."  Many engineers have tried to do this--to varying degrees of success. I know one very excellent engineer who makes very clever practical working things that are uglier than blue mud on a red headed stepchild. But you might do rather better. Haha.

 
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martin 'hoff

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I plan to do both.  I'm an Mech Engr stress analyst by day and I tend to overanalyze everything, but am interested and comfortable getting into the details.  In the end, that's overthinking it for my needs and experience level, but just curious about the design process and how they arrive at the choices they do.
Get the Bethwaite books. Ton of material to geek out about dinghy/skiff design. Go read (there and elsewhere) about Uffa Fox's designs. 

My other (somewhat offtopic) recommendation as an engineer is the Bruce/Coles Heavy Weather Sailing book. Yes, it's about sailing technique, for larger displacement boats but a sizable part of the book is about hull design. Perhaps outdated by now, but damn interesting.

 
One thing rhat does not cut waves is a sunfish boew
Well, that was my suspicion, but didn't want to discount what the guy at the club was telling me.  Thought there might be other reasons that a Sunfish might be preferable besides the bow from a design perspective, but figured it may have more to do with inertia/gravity of the class rather than design/use case.

 




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