Changing building method

[Meerkat]

Let's say you find the perfect boat in carvel, strip plank or cold moulded and you wanted to change it to a "dumber" method like lapstrake or S&G - how difficult would it be, especially lapstrake?

[Wayne Jeffers]

Meerkat,

Lapstrake would not be difficult, especially if the hull has no reverse curves. You'd need to line off the planks, of course. Getting them to look right can be a little tricky if you've never done it before, but certainly attainable. You'd have to figure out the proper scantlings, which should be slightly less than for carvel.

Converting to S&G is another animal altogether. First, the hull shape would have to be right. It's not something you want to try with a round-bottomed boat. ;) There was a good article on the subject by Ted Brewer (I think) in WB about 10 years ago, which described the process at length.

Wayne

[Meerkat]

Wayne; I think you're thinking of a Sam Devlin article on converting a Ted Brewer catboat to S&G for the actor who played the mailman ("Norm"?) on "Cheers". IIRC, Devlin consulted with Brewer on the changes.

FWIW, the boat is/was up for sale fairly recently here in the PNW.

[Meerkat]

Ok, so how would you actually DO this?

[Bruce Taylor]

I think it would help if you named a design, or at least a type of boat.

[Meerkat]

Ummmm....

Length on deck 24'0"
Length waterline 21'0"
Beam 8'0"
Draft 3'6"
Displacement 6,500 lbs.
Ballast 2,400 lbs.

http://www.boatdesigns.com/cgi-bin/store/web_store.cgi?page=allegra24.html&&cart_id=693272_13751

[Bruce Taylor]

Nice Flicka-esque boat.

To begin with, this particular boat is available as a stripper. Since strip is at least as easily mastered as lapstrake (and perhaps more forgiving to the DIY builder) I'd certainly think about that option.

Before adapting a ballasted sea-going boat like this one I'd consult extensively with the designers. This isn't like adapting a Catspaw to lapstrake...you're hanging over a ton of ballast on this thing. You'll need to know appropriate scantlings, of course, and have a pretty clear sense of what changes you might be making to the boat's displacement and center of gravity. Changing the framing could have effects on the interior that are difficult to foresee, if you're not already intimate with the design (particularly on a boat like this one, which makes the most possible use of its modest LOA). In short, I suspect this particular adaptation should be done by a pro, or at least with the assistance of one.

Before undertaking it, I'd ask myself if it were worth going to that much trouble to avoid mixing a few pots of epoxy.

[ 10-31-2002, 08:13 AM: Message edited by: Bruce Taylor ]

[cs]

I've been contemplating a design conversion myself but have hesitated to post until my plans come in (still not here :( )

What I'm going to do is convert from carvel to strip for the Mckie Roth Friendship.

I don't think that lapstrake would be easier than strip, but I don't know.

Chad

[Meerkat]

Bruce; thanks for your input - it was mostly just a thought - a friend is working up a design for me, but I can't help liking this little boat. I best wait to see what hizoner comes up with!

CS; consensus is that lapstrake is not half the trouble that stripping is.

See:
http://media5.hypernet.com/ubb/ultimatebb.php?ubb=get_topic;f=1;t=005829

http://media5.hypernet.com/ubb/ultimatebb.php?ubb=get_topic;f=2;t=002079

[Bruce Taylor]

I like it too.

I'd talk to Norm before writing off strip planking.

There's no question that, on a small boat, lap ply will get you on the water a lot faster. When you've made the hull of a small open vessel you've made most of the boat. However, on a larger boat, with cabin, berths, galley, ballast keel, engine and all the joinery these features entail, the shaping of the hull makes up a smaller percentage of your total work time. The extra fairing and milling might not be as onerous as it seems, at first.

Also, there's more than one kind of stripper (you there in the back row...what do you find so funny?). The threads you posted discuss glassed cedar composite. There are other kinds of strip construction (some not glassed at all, and some not even epoxied).

Norm?

[ 10-31-2002, 04:17 PM: Message edited by: Bruce Taylor ]

[htom]

Conversions to glued lapstrake plywood are going to be trickier than to strip construction, as plywood won't bend and twist like strips will.