Boat design/construction method question

[Jim C in VA]

I have a bit of a twist on the “which boat?” question that is often discussed in this forum—to my great enjoyment. My somewhat related question is “which boat construction method?” To be a bit more specific, I should say that I’m focusing on modern plywood construction. I’ve done some reading—Iain Oughtred’s book on clinker plywood construction and Payson’s book on instant boats, for example. I’ve also watched boat building videos by Arch Davis and Chesapeake Light Craft. Still, I’m rather unclear as the advantages and disadvantages in building, tool requirements, material requirements, final weight, time to build, and other factors among the various methods I’ve read about—glued lapstrake, stitch and glue, tack and tape, screw and glue, and so on. Is there a book or article out there that would help me learn about key differences and how/why they matter? I’ve tried searching the archives but have not been successful. (Perhaps I wasn’t searching on the right terms.)

Understanding the practical building and other differences would help me narrow my search for a good first sailboat to build. I have a fair amount of woodworking experience. My hobby is building 18th century period furniture so I am comfortable with hand tools and fairing curves. However, I have never worked with epoxy, fiberglass, or marine plywood.

My sail boat requirements:

1. Must be beautiful. (Purely subjective, but I like traditional craft—my first boat was a Beetle cat)
2. Comfortable for a family of 4 as a day sailor
3. Trailerable
4. Easy/quick to rig and launch
5. Able to mount small motor for windless days
6. Shallow draft (beachable would be a plus)
7. Reasonably straightforward to build for a first time builder
8. Readily available information resources/advice – from designer or other builders.

I plan to sail in the Potomac River and in protected areas of the Chesapeake. I’d also like to take the boat to Rhode Island, my home state, each summer to sail in Narragansett Bay.

Boats that seem to fit the bill include the Core Sound 17/20 and perhaps Arch Davis’ Penobscot 17. I really like the look of Iain Oughtred’s designs, but do not know if they are too complex for a first time builder or lack the “support group crutch” I might need. John Welsford’s Navigator/Pathfinder also look very intriguing. (I’m ready to move down under after viewing all of the NZ photos!) Although I love cat boats, I think that Bolger’s Bobcat is too small.

A completely different approach I’ve considered is perhaps building two of Chesapeake Light Craft’s Skerry. That way, my family and I would go out in two small boats and give my kids more of an opportunity to sail. It presumably would also make my first boat building experience a bit easier. I figured I could trailer one boat and car top the other. However, I’m less inclined to go this route and build two Skerrys because folks have said it is too heavy to car top on a regular basis.

Anyway, back to my original question. If you can point me to a resource or resources that discuss and compares the various construction methods I would be very grateful. And if you’re not too tired of the “which boat” question, I’d be pleased to hear your comments on my boat considerations or suggestions for designs.

Thanks!

[Keith Wilson]

I like building glued-ply lapstrake boats perhaps more than any other method, although traditional carvel planking is not a viable option because my boats live on trailers. Advantages as I see them are as follows:

- Almost any hull shape is practical; one isn't limited as with sheet ply.
- Can be very good-looking, and very traditional-looking from a moderate distance.
- Relatively light and strong.
- Minimal use of epoxy and fiberglass; I don't sheath the individual planks, just the bottom.
- Minimal sanding and fairing. Epoxy softens with heat, so drips can be removed easily with a heat gun and scraper.
- Minimal framing, very clean interior.
- Lapstrake boats sound nice in the water.
- Not a lot of tools needed, and no big power tools - you can do absolutely all the planking work with a saber saw, a low-angle block plane, and a chisel to cut the gains. I'm sure you're used to keeping your plane sharp, so I don't have to tell you that.

Disadvantages, or at least things to watch for:
- Good plywood is pretty much required. One can get by with ACX fir with other methods, but not lapstrake.
- You have to build a mold, unlike many types of sheet ply construction where the panels themselves define the hull shape. OTOH, this means the critical work is done on the mold, not with $60/sheet plywood. Goofs are cheaper.
- Plank lines show on the finished hull. You have to do a good job lining off the planks, or the result is ugly.
- Requires LOTS of clamps, although you can make simple ones yourself easily.

Several recommendations: Get both Tom Hill's and Iain Oughtred's books. (I haven't seen Brooks's yet.) I prefer Tom Hill's method, in which the stringers on the mold define the plank shapes. His method of cutting the plank bevels makes an exacting job incredibly easy.

I recommend System 3's T-88 glue for lapstrake construction. It's an epoxy that was originally developed for wooden aircraft construction that has been around forever. It's a 1:1 mix that is quite thick and is used for gluing only; no precoating with unthickened stuff, no mixing fillers, just slather it on and clamp.

If you are reasonably careful. know how to use tools, and are used to making reasonnably accurate joints, I don't think that a glued lapstrake would be any prolem as a first project.

The Bobcat is indeed too small for four, even if two of them are small. John Welsford has several boats that would work well, as does Iain Oughtred , and the Penobscot 17 is really nice too. You might also want to look at Bolger's lapstrake Chebacco boat (there's a taped-seam version too). It's a 19' daysailer with a spectacularly comfortable cockpit and a minimal cabin, although a somewhat larger boat.

[ 08-13-2004, 11:00 AM: Message edited by: Keith Wilson ]

[Tom Dugan]

Probably the first step is to get some boatbuilding experience. Don't worry, it doesn't have to be your own boat. :D

Come to the Alexandria Seaport boatshop on Tuesday nights and get some experience under your belt. The Herreshoff dinghy is getting finished off now, and it'll show you how a traditional lapstrake boat goes together. There are plenty of old hands who show up on Tuesdays who'll be glad to answer questions and show you the ropes. Plus there are a few boats "out back" (aka the Potomac River) that might help in your choice.

Just show up around 7 PM, park along Union Street north of the Torpedo Factory and look for the timberframe building floating along the waterfront between Founder's Park and the Charthouse restaurant (actually at the end of Thompson's Alley).

And start getting used to the idea that a boat is not a piece of furniture. :D Tolerances are, umm, somewhat less when boatbuilding.

-T

[Jim C in VA]

Thanks for the tip! I found the website and the boat building photos--very nice! Was that part of a class? Or a some type of club project? I'll definitely plan to stop by. But are you sure these folks would want to talk to someone who wants to build a plywood boat?

BTW, how sloppy do you get to be when building a boat? ;) In furniture making, a few thousands of an inch makes the difference between a perfect mortise and tennon joint and a sloppy one. On the other hands, two turned table legs can differ by 1/8" or more and the most people will never notice. I kinda figured that on a boat that gaps in the hull would require the crew to spend a bunch of time bailing! :D

[Keith Wilson]

How sloppy can you be? Well, like with furniture, it depends on what you're building and where the joint is. Traditional construction needs pretty good fits between the planks, otherwise you get awfully tired of bailing. Epoxy-glued construction is a lot more forgiving, at least for function - aesthetics, well that's your call. Paint and putty covers a lot of mistakes which varnish will reveal. Taped-seam construction is the sloppy builder's friend, since the seams are formed with resin and fiberglass tape. 3/8" gaps before taping are not uncommon. A big difference (and I have a lot more experience with boats than furniture) is that once the mold is made, you don't work to measurements much - as long as it fits together and looks good, all's well. Boats have very few straight lines, and a fair curve take precedence over almost any measurement.

Tom's offer sounds WAY too good to refuse. smile.gif

[ 08-13-2004, 04:35 PM: Message edited by: Keith Wilson ]

[Tom Dugan]

Gaps in the hull are generally a Bad Thing. :D

You set up your molds as accurately as possible - certainly to 1/32nd if you can. But then you start attaching wood to them and you do the best you can. For instance, bending planks around the stations at the bow imparts a lot of stress. If you keep a small boat symmetrical to 1/2" or so, you're doing pretty good.

Some day-to-day work at the ASF is in environmental education with local (VA and DC) schools. Some of the day-to-day work is by the staff and a number of "apprentices" - kids who've had minor brushes with the law but can be straightened out with some guidance. A lot of the kids leave the ASF and go on to do good things. Some don't.

There's a fairly large core of volunteers who come in during the day (retirees) and the Open Shop on Tuesday nights to do some boatbuilding. We were also the ones to run the first Family Boatbuilding events at the WoodenBoat shows in St. Michaels, MD and South Haven, MI, as well as the Smithsonian Folklife Festival this year. Many other places along the way, too.

What was your question again? Ah, yes! Umm, the Herreshoff dinghy got started in a lofting class way back when (, then the construction class, which is what I think the pics are from. But that was only a 7-day class and the hull only got half planked. (Actually a pretty good effort for a week's class). The boat's only getting worked on on Tuesdays now, I think, but we're up to fitting the centerboard trunk and thwarts. A couple of weeks ago I was getting started on knees, too.

Anyway, if you look at the Bevin Skiff section on the website you'll see there's no aversion to plywood. I've been able to learn the fundamentals of everything from plywood/epoxy boatbuilding to cedar lapped planks over oak steambent ribs in that shop. You just have to hang around long enough. :D

-T

PS - This is starting to look like thread hijack. We now return you to your original question...

[Tom Dugan]

To add to what Keith said I'll quote Joe Youcha: "Build to the boat". There comes a point in building a boat that the shape is just what it is, and you build to that.


Tom's offer sounds WAY too good to refuse.
So ya comin' down, Keith? smile.gif

[Keith Wilson]

Long drive for a Tuesday night after work.

[George Roberts]

Jim C in VA ---

While lapstrake plywood is a good method ...

I prefer to use a plank on frame approach. Narrow softwood planks glued together over hardwood ribs. If you do the work well, this type of construction lives well on a trailer.

I prefer it because you get more buoyancy - plywood is more dense than softwoods.

[Jim C in VA]

Originally posted by Keith Wilson:
[QB]I like building glued-ply lapstrake boats perhaps more than any other method, although traditional carvel planking is not a viable option because my boats live on trailers. Advantages as I see them are as follows:

- Almost any hull shape is practical; one isn't limited as with sheet ply.
- Can be very good-looking, and very traditional-looking from a moderate distance.
- Relatively light and strong.
- Minimal use of epoxy and fiberglass; I don't sheath the individual planks, just the bottom.
- Minimal sanding and fairing. Epoxy softens with heat, so drips can be removed easily with a heat gun and scraper.QB]Thanks Keith. This type of comparison is really helpful. (Less sanding is always A GOOD THING in my book.) I also appreciate the tips on the epoxy and boat suggestions. I just joined the John Welsford group on Yahoo to try to learn more about his boats.

--Jim

[Venchka]

Attend the October wooden boat get together in St. Michaels, MD. You will see and maybe even sail enough wooden boats to help narrow your choices. Geoff Kerr is usually there with his Caledonia yawl. There are several Caledonia and Ness yawls in the D.C./Northern VA/MD area. Richard Cullison may be there as well and you can pick his brain. Good luck!

Along the lines of the CS-17 is I.O.'s Fulmar and perhaps Iain's new design SKUA. SKUA hasn't surfaced on the internet yet. Details can be had directly from Iain. His mailing address will turn up in a search of this Forum.

I am partial to the Caledonia yawl to meet all the needs you decribed.

Good luck!

Wayne
In the Swamp. :D

[Jim C in VA]

Wayne,
I have Iain's address and plan to send off a check for his catalog. The Caledonia Yawl is a beautiful boat. I spent some time on the Crazybird website and one comment was that there was not much in the way of details for finishing completing the insides. However, it's good to hear that there are a few CYs in the DC area. Where can I find out more about the event in St. Michaels?
--Jim

[Jim C in VA]

Wayne,
I have Iain's address and plan to send off a check for his catalog. The Caledonia Yawl is a beautiful boat. I spent some time on the Crazybird website and one comment was that there was not much in the way of details for finishing completing the insides. However, it's good to hear that there are a few CYs in the DC area. Where can I find out more about the event in St. Michaels?
--Jim

[Dave Fleming]

Did I read that right?

You work to THOUSANDS of an inch in making Wood Furniture?

M'gosh what do you use for measurements, dial caliper, micrometer, venier caliper?

Working to Hundreds of an inch is too much for me.
Wood moves almost constantly how do you prevent or work around that with such exacting dimensions?

A Bicycle Playing card is approx: .010 inch in thickness for reference purposes

[ 08-14-2004, 09:15 PM: Message edited by: Dave Fleming ]

[Norske3]

The "Cal" is indeed a beautifil boat...light, strong and fast as a witch with afterburn......saw one at the Portland Boat Show....the builder I talked to lives in Yarmouth Maine.

[ 08-14-2004, 10:08 PM: Message edited by: Norske3 ]

[Jon Etheredge]

Working to Hundreds of an inch is too much for me.
Wood moves almost constantly how do you prevent or work around that with such exacting dimensions?
Dave, Dave, Dave...(shaking head) you're behind the times man smile.gif

You should see the tools that guitar builders are using these days. I worked for Bill Collings at Collings Guitars (http://www.collingsguitars.com) for a few years. At the time I worked for him, he was bringing a Fadal Milling Center (CNC milling machine) online to carve necks, fingerboards, bridges, inlays, etc. He has two (or more?) online now. These machines work to thousandths. Martin and Taylor are both using similar machines as are many other guitar builders.

Collings controls wood movement while the instruments are under construction by keeping the shop at a constant 70 degrees and 50% relative humidity. When you add in the air filtration system he has to eliminate airborne dust, it makes for a nice working environment smile.gif

In my home shop, the accuracy is another story though. I agree with you that working wood to just hundredths of an inch in an uncontrolled environment seems like it is pushing it a bit.

[Dave Fleming]

Jon, I wonder what Krenov would say about this working to the gnats arse in dimensions thing?

'Gitters' 'n such I can understand but breakfronts, sideboards? I dunno, I really must be out of touch.

Sigh...

[Bruce Taylor]

You should see the tools that guitar builders are using these daysAs Dana Bourgeois put it, "CAD is the sharpest tool in my shop." It's the realization of something Bob Taylor has been saying for fifteen years: "CNC is the future of lutherie." As tooling prices come down I'll bet a lot of the smaller shops that specialize in custom one-offs will go to CNC as well. I don't think they'll be putting guys like Jose Romanillos out of business, though. People will gladly pay to have his fingerprints on their instrument.

I measure thousandths, when dimensioning veneers for rosette mosaics, soundboard thicknesses, and so on. When a purfling line is out by a couple of thou, the eye can detect it & the fingers can feel it.

Speaking of fingers...cabinet makers work in thousandths, whether they know it or not. They might not pull out the dial calipers when cutting a joint, but they do make minute adjustments to the fit, taking shavings that are roughly .003 in thickness and feeling the results through the callouses on their thumbs. The more experience we gain, the more likely we are to fly without instruments.

Or so sez I, to quote "Doc" Fleming. :D

[Jim C in VA]

Originally posted by Dave Fleming:
Did I read that right?

You work to THOUSANDS of an inch in making Wood Furniture?

M'gosh what do you use for measurements, dial caliper, micrometer, venier caliper?

Before anyone gets the misimpression that I'm some kind of engineer or machinist, I should explain. Some parts of furniture making are that precise--mostly joints. The fingers can feel, and the eyes can see very small gaps and misalignements. Also, traditional glues do not span gaps very well. But I'm not measuring such units, just fitting with a sharp plane or chisel until my eyes or fingers tell me its right.

Most other parts of furniture have big allowances for varying dimensions. I don't do much measuring after the basic piece is laid out. Parts are simply cut to fit--its what ever the wood wants to be.

Okay...I'll go back now to learning about to build boats and why I should pick one method over another in considering potential plans.

Thanks everyone for all of your advice!

[Dave Fleming]

Agreed the finger tips are the best measuring tools for woodworking.

Eyes can be deceived but close your eyes and gently stroke a joint or surface. Amazing what you feel is it not?

[Venchka]

Originally posted by Jim C in VA:
Wayne,
...one comment was that there was not much in the way of details for finishing completing the insides. However, it's good to hear that there are a few CYs in the DC area. Where can I find out more about the event in St. Michaels?
--JimI don't quite understand what you mean about details for finishing the inside of the Caledonia yawl. Admidtedly I gave the builder, John Anderson, his head for a few changes here and there, but the basic parts are are well detailed on the plans. Given the pace of building such a boat, if you get stumped a letter to Iain will set things straight.

Having said that, I have seen 3 Caledonia yawls up close and personal. Each had slight differences inside the planking. That's the beauty of a custom built hand made boat. Each builder can impart his own personality.


Originally posted by Norske3:
The "Cal" is indeed a beautifil boat...light, strong and fast as a witch with afterburn......saw one at the Portland Boat Show....the builder I talked to lives in Yarmouth Maine.That was probably Bill Boyd. 2 hours on his boat HERON in Rockland Harbor at WoodenBoat Show 2002 followed by a few hours talking with John Anderson and PRESTO! Elisabeth Grace was conceived.

That didn't sound right. Y'all know what I mean. :D

Wayne
In the Swamp. :D

[Venchka]

Chesapeake Bay Maritime Museum (http://www.cbmm.org/wh_calendar.html)


October

Mid-Atlantic Small Craft Festival
Saturday, October 2, 10am–5pm
One of the nation’s premier small craft events! Hundreds of amateur and professional boat builders and enthusiasts bring their skiffs, kayaks, and canoes. Take part in demonstrations and workshops, or simply chat with the owners and watch these one-of-a-kind vessels race. Included with Museum admission.

[santone]

How about building a Woodpussy? This 1940's Phil Rhodes design (13" 6" Marconi rigged catboat)is staging a "renaissance". Less than 100 still survive, mostly fiberglass. This 430+lb. boat will easily accommodate 4 folks for an evening cruise around a small Island to see the sun go down. There are three fleets where Woodpussys are raced with great enthusiasm. Visit the new class website at www.uswpca.org (http://www.uswpca.org) and check out the forums. Be sure to view Mark Angliss' comments regarding the plan to have several home builders construct new boats using Mark's suggested cold molding techniques. We project that we can complete a new boat with sail and trailer for less than $4000. there are a few of us who will be ready to go by the Spring of 2005.
Regards,Woodie