Of Sharpies, Skipjacks, and Carolina Schooners

Troy: Do you have patterns for that model sharpie, including the panels' unwrapped shape? See http://www.boatdesign.net/forums/boat-design/free-plans-simple-model-32128.html

THANKS! It's a very handsome boat.

 

I changed the kick-up rudder on my small sailboat to a fixed blade with a long pivot rod rather than the usual pintles. This allows me to lift the entire rudder for shallows. Because the transom is at 22 deg it helps the rudder assembly slide up as it is pushed back to clear underwater obstructions: where I sail there are rocks and the bottom is not too far down. If I have to row the boat I can hold the tiller on the floor with my foot, when the tiller rests on the transom which holds it up but provides just enough immersed area to help tracking. This is useful since I also omitted the skeg that the designer called for. It's a car-topper so the rudder is removable. One cute feature I haven't tried yet; the transom and rudder blade angles are arranged so the top of the blade is horizontal when tucked against the transom: I am hoping this will prove helpful getting back over the stern if I go for a swim, whether vountary or otherwise.

 

This or that Thread?

Folks,

Right or wrong, this Thread has answered my fundamental question about how to finish a stern, but raises another.
That being,,, A highly competent custom Surf Board builder tells me, he uses a dimpled texture to break surface tension at the Boundary Layer.
( I haven't seen it and have no experience with it.)
Irrespective, a surf board surface and a sail boat surface are two different kettles of fish.
I have used " go fast paints", but now wonder if there is an easy, workable, durable surface texture option for hulls?
Is it worth messing with?
Notwithstanding, the recent reference > Laxauskas Doctoral Paper ( post 15) seems to imply it may be worth doing on ships. If it is in those hull forms, it would seem to be more so for a sail boat. Is there a viable solution for sail boats?
Should this discussion continue in this Thread, or start anew?

Bill PKS.

 

Bill, Stephen,

I've had the opportunity to sail several sprits'ls and two masted sharpies and raced and observed their performance against more modern boats, but still of basic traditional design. For what its worth, I'll offer the following observations. The traditional boats are all very reluctant in tacking and usually require some help in the form of backwinding the jib or rudder pumping. I attribute this to the long (fore and aft centerboard), the long immersed chine and a less than optimum rudder. The speed is restricted to displacement by the rocker and the relatively heavy weight of the boat limits the top speed that can be attained.

The more modern and lighter weight boats just sail away from the traditional ones. Their lighter weight, blade centerboards and deep rudders make them faster and much more maneuverable. These boats are available for anyone to sail at the NC Museum in Beaufort, NC at certain times. In addition to the design features listed above, the traditional boats are generally poorly rigged for ease of handling. Their boomless mainsails can be a bear to handle in higher wind and sheet blocks and cleats are often primitive. I never rig a topsail unless running off the wind since I doubt their value when beating. Some sharpies with the sprit booms are much easier to handle. The shad boat is also slow and maneuvers poorly. I have not sailed the periauger but I doubt it fairs any better.

This is not a diatribe against the traditional boats of my area but is a recognition that some advances have been made in sailboat design and construction. Those who still want to build these boats are free to do so but don't expect them to live up to their long outdated reputations (appologies to Mr Munro). Also, don't expect some small modifications to make them equal to the modern designs. They are what they are, which is mainly of historical value and for those who value this attribute above all others.

 

I agree wholeheartedly with you that traditional sharpies are what they are, and people shouldn't expect to miraculously tweak them into the latest and greatest of modern boats. It reminds me of what Bolger said about dories: that if you start trying to improve them for performance under sail, you eventually wind up with something that isn't a dory at all -- thereby proving it wasn't a good place to start from.

But I disagree that the value of sharpies is mainly historical. After all, the attributes which made them so attractive to begin with are still there, especially for amateurs.

Their construction is still easy, inexpensive and robust, and the materials are still available anywhere in the country. They'll still sail in skinny waters where most boats their size don't even think of going. And to me they're still surprising graceful and even beautiful, considering their simplicity. Properly done, a sharpie is a collection of fair curves all flowing harmoniously together.

Yep, I'm biased....

 

Thank you for the compliment, Stephen. Unfortunately, the only design for that boat is in my head; I have no plans for it. I'm building out my ideas, instead of drawing them.

But I started with the two sides. And I can give you the dimensions of those two side panels, if you want to make your own pattern. Everything past that is just eyeballing until you like the results, anyway.

The model is scaled to 1"=1' 0". I started with sides that were cut 29' 0" on deck. The bow is 3' 0" deep, and the stern roughly 1' 3". The sides were cut dead straight top and bottom; the curves you see are what happens when you bend panels around molds. I clipped each end at an angle; the bow is cut at 10 degrees, and the stern at 25 degrees. The transom is 3' 0" on deck, and 2' 0" across the bottom.

I started construction by temporarily taping the sides together at the bow, and to the transom at the stern. Then I inserted a mold amidships that measured 7' 0" on deck and 5' 9" on the bottom, and went from there.

I stuffed spreaders (sticks) in between the sides top and bottom, until I was satisfied with the shape of the hull. Then I cut and inserted molds at 2' 0" on center to hold the shape, while I put a bottom on. Once the bottom was on, I turned it over and started the deck framing.

Hmmm...when I try to write it all down, it comes out sounding more complicated than it really was. It involved a lot of fiddling and eyeballing, but the concept itself is pretty simple. Of course, it may be more of a project than your daughter wants to tackle, since there are no plans -- much less expanded panels.

 

Troy,

You missed the main point of my post. It is not the idea of a sharpie that is so dated. Its the traditional part. That is an overly heavy boat developed for work that has lost its place in the pleasure boat scene . We have lots of modern boats based on the sharpie concept that suffer few if any of the faults I mentioned. Here is one I built (the Loon) that can outsail much larger traditional sharpies.

http://www.bandbyachtdesigns.com/brs.htm

Still, if you want a traditional sharpie, go right ahead, build it and enjoy it.

 

Very nice boat indeed, Tom. thanks for the link. I spent some time wandering around and enjoying the rest of your site, too.

I agree there's no real point in slavishly copying the original working sharpies -- unless you own a set of oyster tongs, know how to use them and have a place to do so. And even then, there's no reason to build with traditional materials, aside from the sheer fun of building and owning a boat that's historically authentic.

By the way, the first three Woodenboat Magazine issues each had an article about some guys who did just that: built a traditional sharpie for fun. The first article was about its construction; the second was a photo essay of it sailing; and the third was a discussion of its handling characteristics.

The pleasure boat based on my model will be plywood construction, and the design has been modified from the original working boats more than you might think. It'll have a little less rocker and draft, somewhat more beam, watertight flotation compartments fore and aft, and masts in tabernacles. And of course it'll have a cockpit and a cabin; an outboard well in the bridge deck; a composting marine toilet in the head; etc.

I cheerfully admit I could probably have a better sailor and more onboard comfort if I strayed even farther from the traditional design, although I expect this one to perform reasonably well. But I'm impractical enough to also want a craft with retrograde looks....the dreaded term "character boat" comes to mind.

 

Good on you Troy. No one really has to have a pleasure boat, we just want them. Well, some of us may really have to have them, and in great number. If a boat does not appeal to you at first glance, it may not get a second one. There is no denying the appeal of the long lines and low topsides of a sharpie. Build one that has this appeal but built in lightweight material like plywood and give it some healthy ballast low down so it can carry a decent amount of sail power, more modern foils that bring the handling up to standard and it should make you proud.

 

The problem with modern foils is that the term usually seems to translate as, "long narrow things, sticking way down below the rest of the boat."

I've had good luck with traditional-style pivoting centerboards in the past, although on smaller boats. They don't stick down that far to begin with. And since they have a shallow leading angle, they kick up easily when they hit a sand bar or you're beaching the boat and don't have an extra hand to raise them.

I obviously don't want fixed dagger boards in the waters where I intend to sail; I'd probably lunch them first time on the water. I've thought about using a pair of smaller pivoting boards instead of the single larger one, and housing them in the settee/berths to either side of where a traditional centerboard would be.

But if I make them like shorter, narrower versions of the usual centerboards, I'm not sure they'll grab enough water to do the job, even with both of them down. And if I design them to drop down to a more or less vertical position, they'll be too far forward.

Then of course, I haven't even mentioned the rudder yet....

What I'll probably wind up doing is building the traditional-style centerboard and rudder, and seeing how the boat handles. If I'm not happy, I'll consider alternatives.

 

Pretty from the Sheer down.

Tom , Troy, Stephen, and Messabout,
I grew up in the 50's on Bogue Sound ( across the moat from Beaufort) sailing Spritsails, Comets, Sailfish, Sotts, and even plasticized cardboard fish boxs. Later, larger boats and windsurfers.
Several friends still have Spritsails, and I bum a ride occasionally.
My point in this was to use the Flatbottom Sharpies and the Skipjack hull forms ( irrespective of weight and foils), to help get my mind around hull speed for a larger project, particularly , how to deal with rocker and how to end the stern.
Troy’ s comments on the reserve buoyancy in the counters of working boats, Stephens reference to Britton Chance’s Mariner , finding the Laxauskas paper re Ships sterns, and Messabouts musings on sterns, brought me to some conclusions on the subject. Now I’m into the Boundary Layer.

Tom, Foin' lookin’ Skiff. I was thinking about a production 14’ Skiff ( iI-14) with two rigs. One for the family and one go-fast , on the idea that surfer dudes get married, have kids but still like the water.. (Also a tent). But so far I can’t find that there is much market for it ( or anything.) The 14’ was because there is no license required (yet.) ( See the PDF.)

Troy, Looks like you have reduced rocker, which ( with light weight) may be the most citical point for a quick hull,,,,and it looks good too..

Perilous thoughts,,,
Capt'n Nat, said 'Pretty does as Pretty is'. (or something like that) , but most folks only see “ Pretty” from the sheer up.
Seems to me, as water is much thicker than air, Performance is mostly from the Sheer down.
A larger issue. I see all the "hard crabs" clinging to visions of gales off the Horn, and engineering for 60’ waves in a hurricane on Diamond Shoals .
So, although most all sail boats will never venture across the Atlantic, or even out into any bad weather, the mystique of the "proper" snug craft braving a gale in the North Atlantic has become the standard for design engineering for sailboats; consequently, the boating public is buying Power Yachts and Trawlers.
Others design soft chine "beginner" boats, that scare -off mom and the kid on first step. And then we wonder why they buy jet skies.
Seems to me there should be some way to differentiate the intended use of a Sail Boat without denigrating the Boat.

Think I'll start a new Thread on the Boundary Layer.
Bill PKS

 

An evil thought?

I built my small sailboat with a daggerboard because the design said so and I did not really know enough to change it. However in the shoal waters where I sail, a pivoted centerboard makes more sense. There may be an impact on performance but I don’t race so I don’t care a lot. But ...

Your idea of a pair of boards has got me thinking. The boards need not be identical other than the usual obsession with symmetry. There can be a long skinny board for reaching and suchlike and a shorter one for downwind and shoal work. Unless the boat is intended to be sailed on it’s ear the effect of an off-center board is negligible. I found that out when I tried a sail rig with a Bruce foil on an outrigger: much the same on either tack.

Both boards can be pivoted inside compact trunks hidden by accommodations. They don’t have to be the same shape; the shoal board could have the common triangular shape to keep the center of area fixed at all depths. Since the long board would be either fully up or fully down, it can have an efficient profile with a high aspect ratio.

If the boards are held down by ballast they'll need to be swept back. Alternatively if a non-ballasted boat is preferred some kind of spring-loaded hold-down device can be devised. For the long board, an over-center spring seems a good idea to provide a high resistance to drag that reduces rapidly as the board is pushed back by an obstacle.

The purists are going to be outraged, but it’s all underneath so who’s know once the boat’s in the water? It’s a little more effort and probably heavier too, but not much. In fact it’s starting to sound like such a good idea that it’s probably already been done.

 

Some of Bolgers designs split the lateral resistance between a large rudder and a board forward much like the Chinese did. These tend to have hard bilges,
relatively flat bottoms, and fairly steep buttock.
http://timkeeshen.tripod.com/thebuildingofstvalery/index.html

I dont know how this would work in a chine design .

 

Stephen D; I agree wholeheartedly with your take on pressure distribution. Somewhere, sometime, someone must have done some real measurements for pressure differentials with respect to stream placement. If that information shows up now it will diminish our fun discourse.

Whatever we call it, Bernoulli or otherwise, we are delving into a study of kinetic energy differences. Marchaj explains that wave generation is a KE thing. He does the explanation quite lucidly. Incompressible water piles up because it has no other way to go, much to the detriment of our boat.

This thread could easily morph into a discussion about bow half angles. We have water moving along a curved (well usually curved) surface. No doubt there are some interactions of both positive and negative pressures. Skinny entry, it seems, would be better than a bluff entry as a result of displacement/time considerations which brings us again to F=Ma. And then there are the multihull folks, some of whom tell us that a hull should have a few parallel sections near mid hull. That notion is no doubt linked to particle recovery time. That design feature is most easily applied to long skinny hulls and is not a realistic option for small dinghy like monos.

Troy: Nifty model! As you describe it, you have done the boat the way the old timers did it. Sides cut with parallel straight edges are an economy of labor, but they do produce a creditable boat. Do it by eye...Thats the way we are told that the old builders did it. Float boats of the northwest are still doing it like that. Flare is closely related to rocker and it generates itself. Neat! Who needs plans? The almost famous Six Hour canoe, a product of the mind of Mike O,Brien, does something pretty similar. The side planks have at least one edge dead straight. Makes a pretty boat too. It is a flat bottomed little thing with double ends. Makes me think of the commodores Egret in miniature. Any picking on Troy's model would include a raked stem so that flare can be carried right out to the stem. Drier boat maybe?

 

Troy, Bill, Terry,

Take a look at the Belhaven on B&B's website I listed above (the centerboard arrangement, not the boat). This is a very neat solution to the problem of a centerboard intruding on the interior of a sharpie or other small boat. We build almost all these boats with an offset centerboard to some degree and it does not seem to bother performance enough to notice. There is really no need for dual boards either, one will do the trick. Several of these boats are called Core Sounds and the name should ring a bell. They do well in the shallows with a normal centerboard and a kick up rudder.

I designed a 30' sharpie some years ago with one CB under the forward V berth and another under the cockpit to keep it out of the cabin. Never built it and think the Belhaven example is a better solution anyway. I'm not a fan of the rudder taking a lot of the lateral resistance. I once broke a rudder off in strong wind just off Royal Shoal on the way to Okrakoke. If there had been a heavily loaded rudder like on St Valerie, I would not have been able to steer well enough to get the boat into harbor without auxiliary power.