30' plywood sharpie

Discussion in 'Boat Design' started by davesg, Nov 4, 2009.

  1. PAR
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    PAR Yacht Designer/Builder

    For quite some time you've (this thread) has drifted away from real sharpies and focused on highly modified things that really aren't sharpies.

    It's difficult to guess at the sea keeping qualities of a craft like this (or any for that matter), without some understanding and experience.

    By this I mean a 30' anything will bridge most of the chop it encounters in all but open water, so it's not bashing it's way through anything. It's not going to fall off waves and slam hard into the next. This isn't to say you couldn't get caught in a situation where you might, but it's very unlikely you'll take a 30' boat out in 15' seas, which is the case you'll need to really see some slamming on vessels this size.

    Bolger's flat bottom box boats took this (and other design considerations) to the purest forms. Dead flat bottoms and slab sided craft, with seemly ridiculous length to beam ratios, not for nothing, but to employ the advantages found in the physics. A 5' wide 30' long boat will glide effortlessly along with next to no power to motivate it to hull speed. Hell, you can just about piss off the stern of a Tennessee and get her to do a knot or two. At this length he also knew the wave trains the craft would meet, wouldn't ever exceed it's ability to slice through, assuming of course the skipper wasn't "Gillian" himself.

    Sharpies as the hull form as really known, is a louse sea boat, unless fairly well burdened, much like a dory, needing half it's weight in fish or oysters on the bottom planks to "steady up". A modified sharpie (one that's had some belly removed and been "beamed" up") acts more like a skiff and is still a rotten sea boat. Of course, place a ballasted board in her, seal up the decks, limit cockpit volume, install tall cabins with lots of crown and you'll recover from the eventual capsizes.

    The skippers of 19th century sharpies where real sailors, so they could handle a 30' boat, with it's 2" thick file planked bottom and 3 tons of fish in the hold, along side a freighter to perform a rescue. These boats and skippers where nothing like what is being passed off as a sharpie today (let alone the skippers).

    Take a better look at those Chapelle drawings. You'll note the runs where "tucked up" a lot more then modern variants. Why? While we're on the subject of the run, these buttock angles just wouldn't permit even the remotest possibility of getting up on plane. They can fall off or skid down the face of a wave, but plane, oh please. You'll also note the amount of rocker reflects the dramatic reduction of displacement worked into the modern sharpie lines. This means the modern variant will not slice through as it's three times as heavy ancestor did, but rather attempt to bash it's way over.

    Knowing this, many not as familiar with the type, have dropped the stem into the water to help cut down on a perceived pounding issue. Of course this sets up a huge lee surge wave train and the boat has to be sailed flat for any performance, rather then using the narrow beam to advantage and burying the forward chine underway, but keeping the entry clear to clean up the flow.

    I guess what I'm saying is get a ride on one of these big traditional and modern sharpies. I've shot breakers in the old school 30' boats and been in really ugly weather in both styles. If we where light, we let in some water in hold and rather then put the board down, we lifted it up. Just enough board was down to keep us tracking fairly straight, but no more. This let the boat "skid over the tops" and swells or breakers would just run under us. Too much board and the boat would do all sorts of undesirable stuff. The new boats behave like what they are, much lighter, beamer, flat bottom skiffs. Survival skills will be similar, though more difficult because of the additional beam, faster roll moment and quicker motion.

    I think what has set me off so much (sorry) is that Egret isn't a sharpie. It's beam/length ratio is 3.1:1 which hardly qualifies it as unusual, let alone a sharpie. Yes, it has a sharpie sheer and other styling clues, but it's a skiff and will handle like one. Even the Sharp End 900, is only 3.75:1 beam/length, making it slightly narrow for a modern vessel, but not so much. Reuel's sharpies are a much better interpretation of the type with Ibis's at 5:1 beam/length ratio. Of course he's had to make "adjustments" for modern living, so the stem is buried and cabins are tall. Even the Bruce Kirby concoctions are considerably wider then typical sharpies standards. The NIS 31' is 3.2:1 beam/length for example.

    The Presto and the sharpie share a common portion of their name, but really aren't very similar.

    Okay, my rant's over . . .
     
  2. troy2000
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    troy2000 Senior Member

    OK, my turn. If I remember right, the beam on Munroe's Egret was only about 5 1/2' across the bottom, whch is the beam that counts on a sharpie. I'm not sure how that translates into 3.1:1. Lessee...got a calculator right here.....yep, more like 5:1. Even at the gunwales, the ratio was only about 4:1. Nor was that beam carried very far fore or aft; it narrowed fairly quickly, and was hardly in the same class as the average square-sterned flat-iron skiff.

    You're right that Egret wasn't a traditional sharpie; no one has ever made any secret of that. Munroe incorporated dory elements into her, too: double ends, a lot of flare, more freeboard, and more rocker than the usual sharpie for her length. She's been referred to as a sharpie-dory or a shorie. But I would in no way, shape or form call her simply a "skiff."

    Nor is what I'm designing simply a skiff. It's going to be very close to the proportions of the original working and racing sharpies. It'll have a long narrrow hull, a sharp plumb bow, and a tucked-up stern.

    I don't have a ton or two of oysters to dump onto the cabin sole; I'll have to make do with some permanent inside ballast instead. I'll be keeping the cabin low and the rig simple, both for stability and for windage.

    And you know what? It might not be a sharpie by your definition when I get done with it, but Chapelle would have no trouble identifying it. He drew and published similar boats, and called them sharpies. I don't think he used the term lightly, although he did make a distinction between a good sharpie cruiser, and some of the clumsy, top-heavy, over-rigged abortions that were also built and called by the same name, saying some of them were downright dangerous.

    You made some good points, but I think you're trying to take in a little too much territory. Just because Glen-L and John Atkins designed some pretty skiffs and called them sharpies, that doesn't mean everyone who builds a modern sharpie is building a simple skiff instead. Nor am I building a skiff. I know the difference.

    I also think it's going to sail just fine, thank you.
     
  3. souljour2000
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    souljour2000 Senior Member

    I haven't studied the Sharpie nearly as much as many of you but I can see how the overall design is very successful for working fisher-folk.With that long skinny "sailing canoe" profile you could leave at 4 or 5 a.m. and ghost out of the harbor on the outgoing tide and night breezes off the land....fill your hold and by the time things get rougher in the afternoon...your stability factor is greatly increased by your catch allowing you to handle a stiff afternoon breeze or T-storm-induced waves if you get caught out without too much pounding on the way home....in the summers most coastal areas have onshore breezes that build until they reverse in the form of t-storm outflow from the land...fishermen would most often have a building but following sea on their way home...a stern design that recognizes that and can accept that nice push-along would have made sense...smart fisherfolk would be back and mending the nets by the time most t-storm outflow off the land made things froggy....if not then the narrow bow entry and length under load would punch thru any big waves as long as you or "Gilligan" keeps an angle into them ....overall an excellent coastal vessel design...for the recreational sailor maybe water-ballast tanks would seem to be a desirable feature...to give you that "hold chock full of oysters/fish to the rafters" stability PAR talked about...
     
  4. troy2000
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    troy2000 Senior Member

    Bolger liked water ballast in his sharpies. He also liked a lot of rocker, slab sides instead of flare, high freeboard and leeboards.

    I'm sure he had good reasons for every one of those features, and I had all the respect in the world for him. But try as I might, I can't get past the looks of most of his sharpies. If I'm going to bust my tail building something, I'd just as soon it be something that looks graceful and pretty to my eye.
     
  5. frank smith
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    frank smith Senior Member

    I think it depends on the design . You are right that they are light flat bottomed boats , but Chapelles double ended 30' could be built for coastal use . I would want one that had a bit of dory in her , good rocker and outside ballast .
     
  6. frank smith
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    frank smith Senior Member

    Good rant . There is a lot of mythology about the sharpie , But not much in the way of first hand knowledge. Any info on the handling of a sharpie , and how changes to form affect handling is a help .

    NIS 31 is really a presto type
     
  7. souljour2000
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    souljour2000 Senior Member

    PAR....have you published any books yet? Your "rants" might be a construed as a tad acidic at times but damned if these threads don't need a healthy dose of "smelling salts" billowing from the bilges from time to time and I like it when you do post one of these classics...

    Thanks for the "Gilligan" reference too...that was also classic...
     
  8. Boston

    Boston Previous Member

    I been reading about how to sail these things
    apparently since they slide around so easily sail handling is a key element in slow maneuvers. For instance you can saddle up to a dock sideways or even bring in her stern with kinda a sliding maneuver, with one sail let out to luff while the other is close sheeted. kinda makes the boat pivot around its middle with the tiller hard over to where the rudder is perpendicular to the keel

    there are some unique sailing characteristics to these boats that I was completely unaware of. Although the more I learn about them the less I believe they would make a comfortable live aboard unless you were talking a vessel of say 50+ and even then I suspect they would be "noisy" on the water

    Gilligan
     
  9. PAR
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    PAR Yacht Designer/Builder

    The unique sailing habits you're reading about are mostly rig related. Unless you've had some time in a cat ketch, you just can't understand how different this can be at times. One of my favorite and a common maneuver was the pirouette. You could come up to a dock or beach, release the sheets and land softly, if timed just right, stopping right where you wanted. Then to get off, you'd "back 'er out" and the boat would literally spin around, usually within 2 boat lengths or less and sail off 180 degrees from which it came in.

    The Chapelle and other "antique" sharpies where not light, especially by modern standards, though in their day they were. These where wooden boats designed to carry heavy loads. I'm not kidding when I say a 30' sharpie would have had 2" thick bottom planks. This was done also to offer some ballast, but mostly because of the weights and shoal abuses they would receive.

    If you took some of Bolger's designs and added some shape to the stem and stern, even leaving the sides plumb, they'd look a lot better.

    When designing these boats it's very important to understand how and why they work as they do. How much rocker (and why it's important), what shape to employ in the rocker, the shape of the chine in plan and how it relates to the rocker used, where to place the displacement and why, do you keep the stem clear or drop it into the water (again and why you'd consider this), plus many other factors make what seems to be a fairly simple design, considerably more complicated then first blush.

    A 30' sharpie is a fairly comfortable boat in deep water, though nothing like what a modern sailor would consider "reasonable". A modern sailor would say it rolls too much, it's too wet a ride (they are wet), there's not enough freeboard, there's not enough headroom, there's not enough elbow room, it's too tender and they'd be right when compared to modern craft or modified sharpies. They have a predictable motion and are not jerky, which is a huge improvement over a modern boat. They move through the water, not over it and slamming doesn't happen unless you're doing something wrong or heeled over good, in a healthy blow and what boat doesn't pound then. These boats as a rule (especially the boats with a buried bow) don't like to turn and as a result they've had some pretty interesting things done to their rudders. Unfortunately, the rudder has little to do with this design feature, so leave it alone to be on the safe side. With a heavy load they can get hard mouthed in a blow.

    It's important to understand which design type you have and sail it accordingly. If the bow is free, then sail it with some heel and keep it "engaged", but if the bow is buried, then you better keep it flat or she'll ***** about it in a blow when heeled over. It's usually difficult to keep a boat flat as the wind builds in strength, which is why most good sharpie designers don't bury the bow (note Bolger's bows). On the other hand, you can make shape concessions and develop a different entry, with the stem buried, but you better have a good idea what's going to happen to your lee wave train, if you want a responsive and fine handling boat.

    I think if most of the posters here had the chance to spend a week on a real sharpie, you'd probably come away not liking it as much. Some of the complaints mentioned above would just eat at you. On the other hand a student of design could make a modified sharpie (what I generically call a skiff), with slightly more elbow room, maybe using some flare to accomplish this, without ruining the hull form, plus other "adjustments" and have a more palatable boat for modern uses. It should be noted that the more plumb the sides, the faster the boat will be, which is why Bolger kept them at 90 degrees, of course the added advantage that the chine logs can be simply cut on a table saw too, also was a factor.
     
  10. Timothy
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    Timothy Senior Member

    PAR . I have to agree with you about the cat ketch rig.I have been sailing one now for almost 30 years now, and I don't think it can be beat for cruising, if your the type of sailor who dreads turning on the engine. Its enough that I have to run it to charge my batteries. Although I have never sailed one I have been speculating based on the sailing characteristics of my own boat that Bolger got it right with the cat yawl ,as I think the mizzen realy adds little to speed, a lot to heel, and really is at its best when employed for manouvering and sea keeping . And although the center of effort is raised a higher aspect mainsail allowed by a small mizzen ( nigel Irens Roxanne) should be beneficial for windward work. When you were describing a more skiff like sharpie for cruising, I was wondering if a hull something like a stretched Goat Island Skiff would fit the bill? I would also like to ask you if you think a hull with more flair on a skiff like sharpie would lend itself to side tanks for movable water ballast? Sorry in advance if these questions are ill conceived.
     
  11. Timothy
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    Timothy Senior Member

    PAR . I have to agree with you about the cat ketch rig.I have been sailing one now for almost 30 years now, and I don't think it can be beat for cruising, if your the type of sailor who dreads turning on the engine. Its enough that I have to run it to charge my batteries. Although I have never sailed one I have been speculating based on the sailing characteristics of my own boat that Bolger got it right with the cat yawl ,as I think the mizzen realy adds little to speed, a lot to heel, and really is at its best when employed for manouvering and sea keeping . And although the center of effort is raised a higher aspect mainsail allowed by a small mizzen (Nigel Irens Roxanne) should be beneficial for windward work. When you were describing a more skiff like sharpie for cruising, I was wondering if a hull something like a stretched Goat Island Skiff would fit the bill? I would also like to ask you if you think a hull with more flair on a skiff like sharpie would lend itself to side tanks for movable water ballast? Sorry in advance if these questions are ill conceived.
     

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  12. PAR
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    PAR Yacht Designer/Builder

    If you take a look at the racing sharpies of the late 1900th century and compare them to the GIS, you'll see they both have very moderate amounts of flare in the top sides. Again, the fast way is plumb or nearly so. The GIS has very little flare, maybe 5 degrees or so, working from memory.

    The GIS's success is light weight and good power to weight, which is always a winning combination. Her flat run and fine entry let her pick up her heels and scoot fairly well in moderate wind strengths. Modern sharpies try the same thing. If you stretched out the GIS, you'd lose relative bearing area and would have to live with higher weight per sq. ft. of sail area, because she'd be more tender and unable to "stand".

    The maneuverability qualities of the cat ketch aren't specific to this rig type, but because the mizzen is taller in relation to the main, it can have a more positive affect on "sail steering". A yawl's tiny mizzen is at a disadvantage in this regard, though it's usually enough to back you out of a slip or keep your head up while tinkering on something. Also the taller mizzen on ketch permits a more effective mule to be flown from it's masthead. This is a powerful light air sail and can really improve abilities.

    Everything is a trade off, so from a design point of view, you have to decide what's important to you. A low aspect divided rig, spreads enough area on a basically tender hull form in the sharpie, to make it a viable option. The GIS gets it's performance from a low aspect standing lug, with plenty of area to get her scooting good. Put this same area in a Bermudian rig and you'll be on your ear all the time. You'd point higher, if your weren't dragging your rail and light air performance would be better too.

    If I was designing one, I'd be working on what I want, not the hull form. What your desires and needs are will dictate what hull form to employ in the design. Building a 30' sharpie is just about as difficult as any other 30' divided rig cruising boat, so it better be well suited to your needs ultimately, sharpie or not. Personally, in this size range there's no advantage to slab sided, flat bottom boat construction. In fact, structurally, it's weaker and heavier then other options, that also look a lot better (round bilge). In smaller sizes it is damn handy to cut a piece of plywood and have half of your bottom planks in one pass with the jig saw. On 30' ketches, this isn't going to happen, so you should be really sure of what you're building.
     
  13. troy2000
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    troy2000 Senior Member

    Par, I once built a flat-bottomed canoe that I had entirely too much fun with. It started out as a Caddo Lake batteau, with 1x12 sides on a fore-and-aft planked bottom. Over the years I added a 6" strake to the sides; a pivoting centerboard; a gaff-rigged main; a boomed jib; a spritsail mizzen; and a rudder with a yoke tiller and steering lines.

    It was horrendously over-canvased, of course. Most of the time I sailed it jib and jigger, standing in the middle of the canoe and hanging onto the tiller lines while I leaned into the wind. Yes, I fell over and got wet on a regular basis; I learned to carry a big fuzzy towel and a change of clothes in my pickup.:)

    I know you can't extrapolate directly from small canoes to fullsized sailboats. But it seems to me the yawl rig has advantages for singlehanding a sharpie, if you make the jib self-tending...and if you have a good downhaul on the mainsail, so you can yank it down in a hurry instead of trying to reef it.

    What would you think of such a rig on a 30' sharpie with a fairly traditional hull?
     
  14. Boston

    Boston Previous Member

    I once built a
    thing
    from scraps and junk left over from my grand daddy's shop out on the cape
    nearly drowned on it and ended up walking miles through the salt marsh back to shore
    was all cut up on eel grass and barnacles by the time I made it home
    after that they let me begin learning in the boat shop how to work with wood
    after many years
    I hope to one day build again some "thing"
    and sail away into the distance
    never to return

    B
     

  15. troy2000
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    troy2000 Senior Member

    I was a full-blown adult when I built that canoe. But you know what they say: "I may have to grow old, but I don't have to grow up.":p
     
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