San Juan sharpies

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San Juan sharpies

Post by TahoeSteam » Tue Mar 07, 2017 5:56 pm

Has anyone extensive experience sailing in calm and rough seas in San Juan sharpies... or any sharpie for that matter?

Experiences, Opinions? Likes, dislikes?
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Re: San Juan sharpies

Post by asal0312 » Tue Mar 07, 2017 7:54 pm

Never sailed in one, but this book has good information on sharpies (design, sailing characteristics etc.). It is available as a google e book.

American Small Sailing Craft, Their Design, Development, and Construction
By Howard Irving Chapelle
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Re: San Juan sharpies

Post by DetroiTug » Tue Mar 07, 2017 11:00 pm

Wes,

On Youtube there are some videos of the "Texas 200", a sailboat run they do in the gulf, I seem to recall a few of them were sharpies. Martin H, the guy that puts that on probably knows quite a bit about them. His boats are the JaniJ (motortug) and the Kanoo (sailboat). He has some very interesting videos as well covering some very common sense home boat building techniques in wood.

-Ron
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Re: San Juan sharpies

Post by TahoeSteam » Wed Mar 08, 2017 6:47 pm

Thank you gentlemen... Over the years I've drawn up several renditions canoe of stern hard-chined v-bottom hulls, but am also considering San Juan sharpies. Somewhere in the range of 36 feet long and 6 feet wide. I know the v-bottom would ride a little smoother, but HOW MUCH? I'd like something easily driven, easily built, seaworthy, and not unbearably rough. Construction would either be epoxy-ply or aluminium... and I'm leaning more towards the aluminum.
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Re: San Juan sharpies

Post by Lopez Mike » Wed Mar 08, 2017 9:48 pm

I've had some conversations with Sam Devlin about steam launch designs. His take is that if you want to have a plumb bow with a single chine hull and want to build it out of plywood, then it is impossible to have the chine follow the curve of the sheer. Ply or metal cannot follow a compound curve.

The solution is to let the chine stay at the water line all the way to the bow. In other words, a sharpie! We have at least one steaming in the N.W. It was built by laying up fiberglass sheets on a smooth flat table and then building a hull with them.
http://media.wix.com/ugd/3c78c8_c27e6f4 ... 3687bf.pdf

Yes, there will a tendency to pound when steaming upwind in a seaway. My experience is that I don't spent enough time in any sort of seaway for that to be an issue. And I navigate a fair bit in relatively open waters, i.e. the Straits of Juan de Fuca. I just don't go boating when the weather is rude or likely to be so.

When I replace my wretched hull I will almost certainly go that way. By the way, it is not that hard to build a curved counter section as an add on. The oldest steamer around here, Uno dating from the late nineteenth century, had such a thing added late in it's life. Looks like it came that way.
http://media.wix.com/ugd/3c78c8_7dd7038 ... 603e69.pdf
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Re: San Juan sharpies

Post by DetroiTug » Wed Mar 08, 2017 10:13 pm

Having built in wood and steel, I'd much rather build in metal. The issue is having the equipment to work in it, but that really only entails an appropriate welder - Mig or Tig for aluminum and steel and then a good Plasma arc like a Hypertherm. With those two coupled with a good little metal cutting bandsaw, then some various hand grinders, one can build about anything in steel or aluminum.

The real advantage in working in metal is that once the panel is fitted and fastened and welds ground out fair, it's ready for sandblast paint. Fit and fasten a panel plywood and the work has just begun, it has to be filled, and then to keep up with contemporary practice - a fiberglass or epoxyglass layer is laid over and then it has to be faired. Many harsh chemicals associated with Epoxy and the dust as well. Then the maintenance on each, an aluminum hull virtually zero maintenance. Aluminum is pretty cheap right now too.

I've been kicking the idea round of building a bigger tug, since I run in freshwater, it would definitely be a steel hull and then wood topsides. If I were running in salt, I would lean more towards the aluminum hull. Aluminum (for me anyways) is a little more difficult to work with, but not much.

-Ron
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Re: San Juan sharpies

Post by Lopez Mike » Wed Mar 08, 2017 10:38 pm

I hear you about the advantages of steel but I've always thought that the weight issues in smaller hulls would be a big deal. By the time I scaled down the plate thickness the hull would be so easy to dent. And if I made it thicker the weight would be really something.

Weight is my enemy for speed and fuel consumption. And I trailer a lot.

Above a certain size, metal is the only way to go. But for my 25 footer I dunno.
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Re: San Juan sharpies

Post by DetroiTug » Thu Mar 09, 2017 3:22 pm

Steel is heavier when it is compared by square foot. When I finished the 22 X 8 tug hull, it surprisingly only weighed around 1300 pounds as close as I could calculate. I watched the component weight closely and was careful not to over-build as I needed to trailer it. I think the same hull built in wood would have been close to it. Where the economy in weight is had with steel is the framing or scantling sizes, much smaller dimensional sizes can be used with equal or greater strength to wood. But as you say on a smaller craft and where the builder risks it a bit and uses larger framing spans or stations, thinner skin material i.e. 1/4 or 3/8 bottom and 1/4 or even 1/8 inch sides, go easy on or omits the glass overlays, those hulls can be kept extremely light. I've looked at plans and seen some of the small tug kits for steel hulls around the web and it's like they purposely add a bunch of unnecessary weight. Deadwoods and keels with big surface area from 1/2" plate. 1/4 X 3 for ribs, 5/8 and 3/4 diameter solid chines etc. it's just overbuilding. My lighter built hull has ran in to lock walls, over stuff (big rocks in Champlain canal), been in rough water, rough loadings and unloadings and it's sound as the day it was built. One big advantage mild steel has over wood and even fiberglass is it can withstand considerable damage and remain watertight.

Aluminum vs wood in a small launch, considering only strength to weight ratio, the aluminum would be the route to go.

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Re: San Juan sharpies

Post by RGSP » Thu Mar 09, 2017 3:25 pm

There used to be (and probably still is) a one-design class of sailing sharpies about 15 feet long, based at Wells, Norfolk, England, which used to be raced regularly both in Wells Harbour (which is fairly sheltered) and in the open North Sea. The North Sea is not a forgiving stretch of water: harsher than any bit of sea adjoining mainland USA.

From what I remember, their performance was very little different from any other class of medium performance racing dinghies.

They were designed to be very easy and cheap to build at home fom a few 8' x 4' sheets of plywood, and I think this aim was successful since the great majority were home built. Some of them were embarassingly scruffy, but handsome is as handsome does, and they worked pretty well. They were always kept on launching trolleys out of the water, which made the very crude hull design very obvious, but their owners and others who sailed them rarely complained.
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Re: San Juan sharpies

Post by TahoeSteam » Sat Mar 11, 2017 5:05 pm

I've done some aluminium welding with tight and a spool gun. For hull a spool gun is the only way to go. You'd spend 20 years welding up a 36' hull with tig!

The v-bottom hull I drew up would displace 6000lbs to be at the waterline. Figuring 1000lbs for machinery (lightweight watertube boiler, "lightweight" engine with cast iron Cylinder block but cast aluminium back columns and bedplate plus associated plumbing), 2000lbs for the hull (hull manufacturer stated 3000+ but they were building heavy for planing hulls that get pounded to death like their fireboats 1/4" sides and 3/8" bottom :o ) , 1000lbs for fuel and water, then add in the extras like life jackets, lines, canopy, dead meat, etc... pretty soon you start get close to that 6000 figure. That was for 36'WL, 7' overall width, 6' waterline width, and about 2' draft
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