View Full Version : Lapstrake sharpies?
troy2000
11-09-2009, 11:31 AM
Did anyone in the past ever build sharpies clinker-style, instead of carvel-planked? Or has anyone done so in more modern times? If not, why not? Especially considering the history of straight-sided Dory boats in this country....
Anyone have any opinions on the advantages or disadvantages of doing so? Assuming of course the sharpies were built with traditional planking, instead of plywood.....
gonzo
11-09-2009, 11:33 AM
Yes, I have seen a few. I like the looks.
alan white
11-09-2009, 12:38 PM
I've always thought sharpies, being shoal draft boats, had relatively flat bottoms and a squarish chine section. This consequently lent to simple flast panel construction using carvel planking and caulked or battened seams, and a faster build time with less waste.
As a result, clinker construction wouldn't have been an efficient build method. The dory lap would have been an exception where adjacent planks could be riveted together between frames.
A modern sharpie would take advantage of plywood construction, and there again, the most efficient method of construction would be flat panels and not clinker.
troy2000
11-09-2009, 02:35 PM
I've always thought sharpies, being shoal draft boats, had relatively flat bottoms and a squarish chine section. This consequently lent to simple flast panel construction using carvel planking and caulked or battened seams, and a faster build time with less waste.
As a result, clinker construction wouldn't have been an efficient build method. The dory lap would have been an exception where adjacent planks could be riveted together between frames.
A modern sharpie would take advantage of plywood construction, and there again, the most efficient method of construction would be flat panels and not clinker.
I was always under the impression that the Grand Bank dories were lapstraked mainly because that was the faster and easier method for an experienced production crew, given flat sides and hard chines (aside from it being easier to keep them tight when drysailed nested on a schooner deck, of course).
Am I wrong? Is it easier to cut, fit and caulk carvel planking instead?
In modern terms, I think sheet plywood construction wins hands down, for practicality and ease of construction. On the other hand, some properly proportioned lapstrake planking could look darned good.....
alan white
11-09-2009, 03:53 PM
I was always under the impression that the Grand Bank dories were lapstraked mainly because that was the faster and easier method for an experienced production crew, given flat sides and hard chines (aside from it being easier to keep them tight when drysailed nested on a schooner deck, of course).
Am I wrong? Is it easier to cut, fit and caulk carvel planking instead?
In modern terms, I think sheet plywood construction wins hands down, for practicality and ease of construction. On the other hand, some properly proportioned lapstrake planking could look darned good.....
Carvel planking would be faster to build, I'd think, than lapped planks, when the panels are flat (like plywood). It may be that dories in rough usage stood up better if lapped and riveted or clench-nailed between frames.
But a sharpie must have been easier to build carvel. PAR knows a lot about those boats. I'd be interested in what he has to say.
You've all managed to nail it down. We must remember what sharpies are (okay were), expendable workboats. By the very nature of their trade, any extra effort wasn't "cost effective". Even the metal work on most, like the "slippery" rudder shaft and it's fitting where usually mild steel. Sure it would rust, but slathered in goo until it was too bent to work any more and made thick enough to absorb any corrosion, with a strength reserve. These boats died a quick, painful death for the most part.
As they became "yachted up" some had their topside "rolled". I've only seen one or two like this and they were larger sharpies (25' - 30'). Of course it increased the complication of the build, but it was lighter.
A carvel guy will recommend carvel, a lapstrake builder, lapstrake. Lapstrake is fast and easy, once you get your head are the peculiarities of the type. Carvel is similar in this regard and much easier to repair. Lap is slightly faster, mostly because all the work can be done on the bench (where it's easier), rather then on the boat like in carvel. Both have their merits.
Most sharpies where "dory lapped and fastened". A technique still used today on many different types of boats. Advertisements in the first half of the 20th century would have exploited this. Terms like "dory fashion" would have been the catch phrases for small craft ads. They would also have told of the virtues of file planking.
I personally think any boat will look better as a lapstrake. They also make the coolest sound underway.
troy2000
11-10-2009, 01:16 AM
Par, what do you mean by having their topsides "rolled"?
Instead of being "slab" sided as if made of plywood (conical or cylindrical development), the sides have compound curves, which is possible with lapstrake.
gonzo
11-10-2009, 06:04 PM
You can give the first strake a lot of flare like that.
troy2000
11-10-2009, 08:31 PM
I see....thanks. Looks like I need a better dictionary, or more time around people who speak the language.
Here's a random thought on keeping dry-sailed lapstrake boats tight: how would it work if you skinned the sides in 1/4" ply, then applied lapstrake over that? If you used fairly narrow planking that didn't move too much when it got wet or dried, you could fasten your laps right through the plywood....
It would work, but you'd have wedge shaped pockets of air between the two skins and you'd also be married to the slab sided look. Of course those pockets would eventually harbor beasties that intend ill will toward your planking. Lapstrake planking, either traditional or glued lap isn't that hard to do. The novice has difficulty getting a brain around it, but once they do they quickly get the hang of it. In other words, I don't see the need to plank a boat twice, just for a faux look.
troy2000
11-10-2009, 11:34 PM
It would work, but you'd have wedge shaped pockets of air between the two skins and you'd also be married to the slab sided look. Of course those pockets would eventually harbor beasties that intend ill will toward your planking. Lapstrake planking, either traditional or glued lap isn't that hard to do. The novice has difficulty getting a brain around it, but once they do they quickly get the hang of it. In other words, I don't see the need to plank a boat twice, just for a faux look.
Well, I did say it was a random thought; it crossed my mind about thirty seconds before I typed it.;)
I'm married to the slab-sided look anyway, if I'm building a fairly classic sharpie hull. So that doesn't bother me.
Maybe I could consider the wedge-shaped air pockets to be reserve buoyancy?:p You're right though; even in a dry climate, it's easier for water to get into wood-enclosed spaces than it is to get it out again....
I have no problem wrapping my mind around traditional lapstrake; it's the only method I've ever used. It's carvel planking that scares me....
Getting back to the subject: I'm looking at building a sharpie that will mostly live on a trailer. Obviously, plywood is the practical choice. Then again, if I just wanted to be practical I'd buy a Clorox bottle with a sloop rig, and be on the water next weekend. If I were being really practical, I'd forget the sails and concentrate on making a camping cruiser out of my old 19' Astro runabout. There's almost enough open space in it to hold a square dance, and you can't get more reliable than a 235 Chevy engine hooked up to a Mercruiser stern drive.
But if we're going to balance practicality against the insanity of wanting a sailboat on desert lakes to begin with, here's another thought: a thirty-foot sharpie at rest will only have about a foot of the hull in the water at the deepest point. Possibly even eight inches, if we fudge the old designs for recreational use; the originals were designed to carry a load. So how about just making the garboard strake out of plywood, making it a little wide, and bedding the lap between it and the next strake up?
Or maybe if I'm going to go that far, I should just give up and build the whole thing with glued lapstrake plywood. Somehow though, I just don't get the same jollies out of planing plywood that I do from smelling and handling the shavings from pine, cedar or other woods....
Johnnylee
11-11-2009, 03:09 AM
Great info guys, thanks for sharing
gonzo
11-11-2009, 03:31 AM
There are plenty of designs for lapstrake plywood. They are usually epoxy glued at the seams. The laps are structural
On most sharpie designs, you could use a common curve for the topside planks and have a "rolled" topside that would look good done lapstrake. Say a segment of a 16' diameter circle (just an example). Rest this circle segment against the chine and sheer marks at each station and draw the curve. Line off the hull for your planks and butt the lowest strake against the garboard (fillet the inside).
troy2000
11-11-2009, 09:03 AM
That's a very interesting idea, Par. If I go with planking instead of sheet plywood, I'll seriously consider doing it.
And by the way, I think I blew my vocabulary again. When I talked about making just the garboards out of plywood, I was speaking of the first plank, the one that fastens to the chine. But I guess the first plank is only a garboard on a round-bottomed hull, where it fastens to the keel. What would the first side plank on a chined hull be called?
troy2000
11-19-2009, 01:06 PM
Another question on planking, whether it be carvel or lapstrake. Chapelle says that working sharpies were generally '3-plank' boats; they had three planks to a side.
My question? The sides on those sharpies tapered from three feet or more at the stem, to not much more than a foot at the stern. Were those three lines of plank tapered and carried from stem to stern, or did the first (and maybe even second) strake die into the chine, and use stealers to get rid of the long, pointed ends?
gonzo
11-19-2009, 01:53 PM
You have a first, bottom plank with a lot of shape in the bottom edge. The other two are parallel.
troy2000
11-19-2009, 02:57 PM
You have a first, bottom plank with a lot of shape in the bottom edge. The other two are parallel.
Keep in mind that I'm pretty much a lone nut case out here in the desert, surrounded by fiberglass ski boats. I haven't had the advantages of hanging out in traditional boat crowds all my life. So I have a fair amount of book learning, piled on top of my experiences with my own creations. Like most self-taught people, that means there are probably gaps in my education big enough to drive a Mack truck through....
But unless I'm wrong, there shouldn't be much shape in the bottom plank either. I've built smaller skinny skiffs and flat-bottomed sailing canoes in the past, with sides that were shaped dead straight at the chine and the gunwale. The sheer and rocker came from how the bottom and the topsides beam were tweaked at stations, not by cutting curves. My dories, on the other hand, had shaped planks...sometimes to an extreme.
Never mind all that, though. You're saying the three planks in the traditional sharpies were carried from end to end?
gonzo
11-19-2009, 03:02 PM
The Chapelle sharpies are all three planks. He even had the layout for them in some plans.
troy2000
11-19-2009, 03:19 PM
The Chapelle sharpies are all three planks. He even had the layout for them in some plans.
Thanks. I hadn't noticed a planking layout in the Chapelle plans I've been looking at. Of course, I've also been bellyaching about the illegibility of what I've been looking at.;)
I started working on a scale model of what I want last night, so hopefully I'll have something tangible to show for discussion shortly. Of course, work is getting in the way, and the family expects me home for a couple of days for Thanksgiving. It's most annoying when life interferes with what I'm really up to....
I changed my mind about the size of the model, though. I was going to build it at 1-1/2"=1'-0". Then reality reared its ugly head again. I'll be dragging it between two houses, the motor home I stay in while working, and work itself, and doing that in a Nissan Frontier King Cab that will also have my Beagles, guns, tools and dirty laundry in it. I decided it would be insane to carry a 45" model sharpie around under those conditions; one 30" long is going to be bad enough.
The planks were not usually parallel, though they looked like it. The hull is "lined off" and the distanced portioned up. The shear plank was typically slightly taller (wider) then the second one down. It was also often slightly thicker too. All reduced in width until after midships, then increased in width (again) towards the stern.
gonzo
11-19-2009, 04:26 PM
The ones I've seen in North Carolina, including new motor skiffs, get the upper planks edge set.
boat fan
11-19-2009, 06:31 PM
That's a very interesting idea, Par. If I go with planking instead of sheet plywood, I'll seriously consider doing it...
Why could you not use this with plywood also ?
gonzo
11-19-2009, 06:35 PM
You can lapstrake with plywood too.
I don't understand the question. You can lapstrake compound curves regardless of the the planking material. Unlike other methods of building, lap doesn't require or need edge set to work, so long as the planks are shaped properly.
gonzo
11-19-2009, 06:40 PM
Sometimes when you cut a board it springs and it take a bit of edge set to get it back.
boat fan
11-19-2009, 06:56 PM
I don't understand the question. You can lapstrake compound curves regardless of the the planking material. Unlike other methods of building, lap doesn't require or need edge set to work, so long as the planks are shaped properly.
Yes PAR excactly.That was my point,
If I go with planking instead of sheet plywood, I'll seriously consider doing it...
In the quote above ,the way this is written , it sounded like troy 2000 would only use it with "planking" i.e. Solid lumber lapstrake.....?
I would use your method with Plywood.
Using that universal arc would look excellent !
troy2000
11-19-2009, 08:04 PM
Yes PAR excactly.That was my point,
In the quote above ,the way this is written , it sounded like troy 2000 would only use it with "planking" i.e. Solid lumber lapstrake.....?
I would use your method with Plywood.
Using that universal arc would look excellent !
I didn't mean to imply I would be restricting myself to solid wood planking; glued lapstrake ply would do just fine. But of course, sheet plywood wouldn't work; you'd never get it to wrap around the compound curves.
boat fan
11-19-2009, 08:59 PM
O K , understood troy.......just a matter of my interpretation....internet can be like that sometimes my apologies.........:)
I think if you built it like PAR`s drawing in glued ply lap , it could look stunning.
Yes, you can get lapstrake planking to fit around compound curves, both solid lumber and plywood planking. One of the nice things about plywood is the ability to cut really odd shapes and have reasonable cross grain strength, where solid lumber planks would need to be steamed to other wise fit. I can lapstrake a football (American) with plywood or solid lumber, but it would be easier with plywood.
The "universal curve" isn't a new idea. It's commonly referred to as a common curve section. Decks are often done this way for the crown and boats with "arc bottoms" too. Of course it's shape limiting, but can make a fairly bland slab sided hull into a more shapely one, with reasonable ease.
Given a choice, I'll plank a lapstrake with plywood every time. It's not prone to splitting, holds fasteners better then the usually species of softwood used in lapstrake builds. It's tough, you can cut odd shaped garboards without having to hold you jaw just right and used in a glued lap build, about as light a boat as you'd want or could build with any other method.
boat fan
11-20-2009, 01:18 AM
Given a choice, I'll plank a lapstrake with plywood every time. It's not prone to splitting, holds fasteners better then the usually species of softwood used in lapstrake builds.
Yes , no cupping or splitting is nice , I would even go to the trouble of capping each plank edge on the exterior .
One question on lining off : Is it best to follow line of flare angle , or do you divide along a vertical line from chine to sheer ?
There are a lot of ways to do it, but none are any more "correct" then any other. I've seen them done on the "diagonals" which actually works out fairly well, others very carefully use percentages of the vertical distance at each station, others like myself give the sheer a little extra for looks, then split the vertical distance equally at the stem and from the tune of the bilge up at midship and the transom. Ultimately, you have little choice but to just give yourself a ball park range and then "make them sweet" by eyeball. You have to make allowances for the shape of the boat too. Some places the curves may require smaller width planks, others may permit wider. There's no substitute for a lining batten. In fact, when I design a lapped boat, I line the profile off by hand and scan these into the machine. The computer screen is too small to really see how well a lined off hull actually looks, you have to have it big enough to see. Since I don't have a 36" monitor, I do it by hand.
Is it best to follow line of flare angle
I'm not sure what this is . . .
boat fan
11-20-2009, 04:06 AM
My question ( lining off ) was specifically for sharpies PAR ,
it`s clear now that it`s actually more art than anything else.
The red line was what I meant by flair angle..
Yep, it can be worked out with ratios, percentages, etc., but the real test is if it looks good by eye. The act of lining off is an eyeball thing and one of the testaments to a builders skill.
View Full Version : Lapstrake sharpies?