Historical multihulls

Hi Richard, sheet plywood hulls have longitudinal stringers on similar spacings as the plank widths of a lapstrake hull, which are considerably larger, so, more material,so heavier than the amount of extra ply in a glued lap. You are right about the fairing issue, all those laps need to be very fair curves otherwise they would stand out like dogs balls when you get a shiny paint job on it, so it probably demands a higher skill level even though it is not difficult work. I hadn't thought of the noise aspect, good point.

Steve.

 

IIRC, there were still stringers in the hulls (but the last time I went on a Spronk it was in 1982 so I may be wrong)

 

If you go further back there are many examples of lapstrake and caravel boats built on the same model with the lapstrake proving quicker. On your National dinghy it may well have been a weight difference that tipped the balance.

As I read the Spronk discussion he made them with glued lap and frames and others with the stringers and ring frames. Done with stringers it is very easy to get fair planking lines right off the stringers as you build saving time. The small amount of wood in the overlap is still lighter than the other methods. I think the biggest plus is using less epoxy for a round hull. I don't think you'd notice much noise difference at speed. Once the Nicol is running past 9 knots the noise is there anyway. It would be more noticeable at slow speeds i think but not enough to really make much difference.

 

Actually you can use temporary stringers that don't stay in for lining off the planks and you rout the planking to them. I wouldn't speculate whether it would be lighter or faster but I do think its a viable method for building long, skinny, light and to my eyes, attractive hulls. Back about 1980 I built all the templates and assembly jigs for building a 21ft Nelson Zimmer designed lapstrake plywood runabout as a full production boat, for a startup operation called Murphy boats. It was similar to boats like the Thompson, Skiffcraft etc. It would be much easier to build long skinny hulls.

Steve.

 

Yes, that is a good method of lining off. The best reason for building lapstrake is undoubtedly liking the way it looks. The weight can be measured though.... the speed would need testing but Spronks held the record for the passenger mile in the Caribbean for quite a while. A ply dory hull shape would be lighter but then it isn't a round hull.

I like the Thompson method of fastening for the glueing. The planks are glued and use machine screws with nuts for the fasteners. You can fit and drill dry then glue and assemble with power drivers for speed. No misalignment or shifting as can happen with clamps.

I learned lapstrake the traditional way on small craft. With wide beam you end up with some pretty wild plank shapes for sure.

 

documentary on the 1980 OSTAR following Mike Birch and Bob Lush.

http://www.nfb.ca/film/singlehanders#temp-share-panel

 

I love these old documentaries, it was cool to see, tied up to Bob Lushes boat in some of the pictures was American, Tony Lushes modified yachting world diamond, One Hand Clapping.

Steve.

 

Great documentary, a good companion to the American film of the US sailors in the race. Birch's boat is a Newick 3 Cheers MK2 or 3. I always thought he was closer to North America when the boat was damaged, it was surprising he still kept coming. I know at least 3 boats were built at Walter Green's yard for the race including the winner Moxie but don't remember if Olympus Photo was among them. I've always wondered if he hit a wave wrong or if a wave with a chunk of drift came up and hit the wing.

 

Someone on another forum was talking about old US steamships from the 1800's

Some of you may not know that almost the first steam powered vessel ever built was a powercat. It was launched in 1788 in Scotland

See here

http://en.wikipedia.org/wiki/Patrick_Miller_of_Dalswinton

and here

http://www.gutenberg.org/files/31179/31179-h/31179-h.htm

So if anyone says to you "your powercat is a dangerous modern invention" you now know what to say.....

Richard Woods of Woods Designs

www.sailingcatamarans.com

 

Really old multi's...

Here are a few historic multi's...

Photo 1: Ceylon, circa 1890's. Check out the interesting rig.
Photo 2: Marshall Islands proa, circa ?
Photo 3: Bora Bora, circa ?
Photo 4: The file name for this image says "Tepuke 31".

I just started reading this great thread so hopefully these are the first time these photos have been posted.

 

Many thanks Richard. Beautiful and illustrated paper about the 18th cent power cat in Gutenberg (one of my favorite sites...)
Also thanks Magenta for the pics. I remember a You Tube video I saw ages ago, I'll try to find it. The Polynesian praos are marvels of design and building.

Some video I've found in a very fast search. There are plenty.
http://www.youtube.com/watch?v=KXt4PL2R1aU Tepuke
http://www.youtube.com/watch?v=LQ0VS6jubDk Outrigger Marshall Island's-National Cup Race
http://www.youtube.com/watch?v=WHhgGeH8YZw Guam Chamorro Voyaging Canoes
http://www.youtube.com/watch?v=I7nXev2Jt7g Sacred Vessels: Navigating Tradition and Identity in Micronesia Part 1 of 2 (1997)

Les last video is very interesting as it has sequences of the construction and they masters of the adze...For those who are interested in ethnology and traditional boats.

 

This just popped up over at SA, thought I'd bring it over,

http://www.youtube.com/watch?v=n83xc0qx5J4#t=915

 

Neat video of Bullfrog.
Tripods are such a great invention.

 

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Great-thanks!

 

The te puke is a proa design from the Solomon Islands, mainly the Reef Islands and the Duff (Wilson) Islands.

http://www.pacifictraditions.org/vaka/launch.html

Nthropologist Dr Mimi George was a former partner of the late Dr David Lewis, who was laregly responsible for the promotion of ancient Polyneisan navigation techniques, and of their multihull craft, back in the sixties and seventies.

He wrote numerous books about various voyags and voyagers. Google him for more info and titles. All a good read.