Lapstrake canoes

You don't know which boat you should build to suit your personal needs? Please post your questions here and our many contributors will surely have some good advice.
Post Reply
Devon Jon
Posts: 2
Joined: Tue Dec 04, 2007 1:24 pm

Lapstrake canoes

Post by Devon Jon »

I am in the process of selecting a design of canoe to build. However, I am an advocate of lapstrake construction and have built dinghies this way before.
Does anyone have experience of modifying strip plank plans to suit lapstrake?
I realise that this may sound a little odd, but a well planked lapstrake hull is a thing of beauty and very strong and light.
User avatar
Scot T
Posts: 84
Joined: Wed Jul 14, 2004 2:45 pm
Location: Victoria, B.C., Canada

Post by Scot T »

I don’t think it is an odd notion at all. I am in the process of researching this very issue, as I can not tolerate the epoxy and have moved on to cedar/canvas and lapstrake construction techniques. I’d be happy to pass on what I’ve learned so far.

A good buddy of mine is a professional boat builder of small craft of various types. According to him, any design that was intended for or modified for strip building is perfectly acceptable. This would include all the designs in the Canoecraft book (both editions).

There are a couple exceptions he suggests would need a little “tweaking”. The first one is the new Freedom 15’3” Solo. This modification is considered only because of the unique tumblehome chine. His suggestion is to redraw it to a more traditional tumblehome curve (which would be very simple) or “Go for it!” and pull off some very creative advanced woodworking and follow the plan as is. I think that would be spectacular…not sure I’m up to it though.

The second issue pops up with the original traditional designs that have a severe hollow along the waterline near the ends. This would be found in the Bob’s Special and maybe various members of the Chestnut Prospector family (although, not so much). This area would need to be relaxed a little to allow for an easier time planking. I believe that these hollows have already been dealt with when Ted Morres revised the plans for his version of these classics so one would not have to be concerned if using these designs.

Rollin Thurlow has an interesting method for transferring from one construction method (wood/canvas) to another (lapstrake) here: http://www.wooden-canoes.com/canoes/skimmer.htm. He doesn’t say much about it but a lot can be gleaned from studying the photos. He uses 7/32” planking over ¼” ribs placed 4” on center. It is a pretty straightforward process as long as one subtracts the thickness of the planking (1/4” more or less depending on the dimensions being used) from the station forms. In Canoecraft the thickness of the ribs are already dealt with in the table of offsets as it’s the same thickness as the ¼” strips most often use for strippers.

I’m not sure how he deals with the garboards. I would suspect there is something to tack onto along the keel line…a keelson?

Hope this helps.
User avatar
Scot T
Posts: 84
Joined: Wed Jul 14, 2004 2:45 pm
Location: Victoria, B.C., Canada

Post by Scot T »

Sorry about the link. I added a (.) at the end. Try This.

http://www.wooden-canoes.com/canoes/skimmer.htm
Devon Jon
Posts: 2
Joined: Tue Dec 04, 2007 1:24 pm

Post by Devon Jon »

Thanks for that Scot, much appreciated.

Looking through the Bear Mountain catalogue I think the most suitable design is the Cottage Cruiser as it has an easy sheer line. I am planning to build in ply/epoxy, so with 4mm sapele ply it should be light. As you say , it would need a keelson to fix the garboards to, but this could be oak or iroko and would only be as wide as two plank laps [about 32mm or 1 1/4'' ]

The biggest job would be working out the planking to make the hull look fair.

I can't see any problems with building it this way, there is no need to sheath the hull with glass and epoxy and with a varnished finish should look stunning.
User avatar
Scot T
Posts: 84
Joined: Wed Jul 14, 2004 2:45 pm
Location: Victoria, B.C., Canada

Post by Scot T »

The design that I have in mind tackling is the William English 20, which is detailed in the first Canoecraft book (1983). It was a design intended for the original cedar strip technique. And I'd be doing it clinched lap.

http://www.collectionscanada.gc.ca/inno ... 820-e.html

It's a 16' narrow beam (31") vee bottom racing canoe. I think it would be a fun solo boat or set it up for sailing. I checked with Bear Mountain and they don't sell the plans anymore but it can be lofted from the offsets provided in the book.

http://www.heirloomcanoes.com/William%2 ... mpany.html

I don't think the Cottage Cruiser or the English would be too hard to get a nice flow to the lines. I prefer the look of an odd number of strakes (seven). There are some photos of lapstrake canoes on the web that use five (look too big IMO) or six per side and they look bland and cheap to my eye. That odd number just is an unconscious eye catcher. It also gives one a little more to work with to get a nice curve around the bilge.

When you get going I’d be very interested in the project.
Post Reply