Benefits Of The Lapstrake Hull Design

[Far2hip]

As a newbie to the boat scene (in regards to ownership. I've been the pilot and docking ace for many others, lol), I was given and old 1962 Traveler Polaris 14 foot runabout and one of the things that really caught my eye was that lapstrake hull design. Just looks beautiful. I have read a few things about the benefits in stiffness and keeping down misting for a drier ride, but can any of you shed some light of experience of advantages between the smooth vs. lapstrake designs? This may have come up before so if this is one of those newbie repetitives, no offense taken if directed to another post stream. Thanks!!

 

[mf70]

You know the primary benefit already.

 

[GA_Boater]

Wood boat simulation, that's all.

 

[jbcurt00]

Marketing

And as you noticed, lapstrakes are nice looking.

 

[Frank Acampora]

The strakes on the bottom "grab" the water for better turns and the hull handles better in rough water. However, on a 14 foot boat you certainly won't see much advantage--almost any water is rough for a boat this size.

 

[Ned L]

As was mentioned, in 'plastic' (fiberglass) it is mostly to replicate the look of wood construction. I suppose given the convolutions in the surface it will create a slightly stiffer panel than smooth glass of the same thickness.
.... Now if you want to talk about wood boat lapstrake construction I'd be glad to do that. I currently have three, from 9 ft up to 33ft, and love the work and restoration of them (white cedar planked, not plywood). Also, just sold a 'glass lapstrake racceboat that does 70.

 

[Willyclay]

Ned L, don't want to hijack this thread but do you happen to know if the Barbour lapstrake boats built in New Bern, NC in the 50's & 60's were plywood planked or some other wood? Thanks!

 

[Far2hip]

Hijack away my friend! I love learning all this stuff! Frank, do you think I may realize the benefits of a drier ride in a smaller boat like this at all?

 

[Grub54891]

Ned L, don't want to hijack this thread but do you happen to know if the Barbour lapstrake boats built in New Bern, NC in the 50's & 60's were plywood planked or some other wood? Thanks!

Wow, I have a Barbour boat. I could never find out if it was a kit or mfd ride. It needs to be restored now, next project, but she is a good looking boat when polished up!
She has lapstrake sides and plywood top, and bottom.

 

[Ned L]

Ned L, don't want to hijack this thread but do you happen to know if the Barbour lapstrake boats built in New Bern, NC in the 50's & 60's were plywood planked or some other wood? Thanks!

All the lapstrake Barbour boats I have been familiar with were Plywood lapstrake, .... Actually sheet plywood bottoms, sawn frames & hard chines.

 

[Willyclay]

Thanks Ned L. Great info about great old boats. This is what makes this forum the best resource around!

 

[Ned L]

The laps in lapstrake construction may tend to act a bit like splash rails and keep a bit of spray down, but honestly I think the effect is that small that it isn't really noticeable (in any size boat).

For a real brief synopsis of lapstrake boat building in the U.S. (for boats larger than just little runabouts) I would say that the technique came over to the U.S. from the Scandinavian countries (Denmark, Sweeden) and from the UK (Scotland) and landed in New Jersey. The construction technique was ideal for the requirements of the commercial fishermen in 19th century New Jersey. You see, the Jersey shore is a 110 mile long stretch of continuous beach with only about 4 - 5 inlets along it, and an extremely fertile fishing ground. Being very close to New York City this created a real demand for Jersey caught fish in the 19th & early 20th century. All that beach and so few inlets forced the boat builders and fishermen to develop a type of boat that could work off the beaches and be ?dry sailed?. Lapstrake construction is a light, flexible type of construction that can take some drying out while still staying tight (all of which you want for working through the pounding surf every day). ........ Lapstake construction has absolutely no caulking when built new.
As 20[SUP]th[/SUP] century came (and the marine engine) the boats that fished off the beaches were perfect candidates for the early engines. The small boats of the 1800?s (16 ? 20ft) grew in the early 1900?s to average about 30ft (running off the beaches every day), and in the 1940?s some grew to 42feet, still working off the beaches of the Jersey shore every day. (These were the ?pound boats? of the Jersey shore.)
Also in the early 1900?s, as recreation became more common, the boat builders of New Jersey adapted their boats to the pleasure boat market and developed the ?Jersey sea skiff? that became popular all up and down the east coast, and was often copied (Chris Craft and others copied the popular Jersey sea skiff ).

When building a traditional lapstrake boat, the keel plank, stem and transom are set up, a series of molds are set up and the hull is planked, then the ribs are steamed and bent into place afterwards. All fastenings are copper rivets.

 

[Ned L]

Here are some pound boats in Long Branch N.J. in probably the 1920's. These boats are about 32feet and were kept on the beach every night.

In N.J. lapstrake boats were built up to about 50 ft. This is a custom built 47ft sport fisherman ("Glenn Echo Too"), built for a customer in Bermuda.

 

[Grub54891]

My Barbour is real lapstrake sides, just the plywood on the bottom and top.

 

[Willyclay]

My Barbour is real lapstrake sides, just the plywood on the bottom and top.

Always wanted a Barbour! Pix?

 

[Grub54891]

I'll have to pull the cover, pull it out an d clean it up, all that jazz. I plan on doing it before fall as I like to run the motor occasionally.

 

[Ned L]

If anyone is interested in seeing how lapstrake boats are built might check this out that I posted a couple of years ago.

http://forums.iboats.com/forum/boat-...e-jersey-shore

And if you would like to see the impact of the Jersey shore on lapstrake boat building might like to check this out that I have running on another forum.

http://www.thehulltruth.com/boating-...fishermen.html

 

[JimS123]

"Old" boats (wood of course) were plank or strip construction, and all tended to need soak time or they leaked. Now, I'm talking about "regular" boats like we all have, not millionaire yachts.

Lapstrake was a big improvement. Later models that used 5200 between the laps almost never leaked. Most used clinker nails with washers, not rivets.

These improved boats had excellent buoyancy (because of the wood) and could handle even heavy water. No boat has ever been built that could equal a pre fiberglas runabout.

Along came fiberglas, and many copied the design strictly for aestetics. The dense glass never performed like the old woodies. To compensate, more and more HP was added.

So, what do we have today? Heavy boats with high HP and high gas consumption. Acceptable "Performance" requires trim tabs or hydrofoils or adding even more HP.

I like the analogy of an old airplane....if the motor failed it could still "fly", and coast down if necessary. Today's jets are held in the air by pure thrust alone. Cut off the engine and they fall like a rock.

Ahhh for the good old days. "If God had intended boats to be made out of fiberglas, he would have created fiberglas trees."

I have a deep V tinny and a glass I/O. My little Lyman with a little OB outperfoms both in heavy seas in Lake Erie.

 

[Willyclay]

Well said JimS123!!!

 

[Ned L]

....."Lapstrake was a big improvement. Later models that used 5200 between the laps almost never leaked. Most used clinker nails with washers, not rivets." ......

Well,....... To say lapstrake was an "improvement",.... The technique is more than a thousand years old, not exactly new.

Chris craft used Thiokol in the laps, not 5200. Chris Crafts were also all plywood planked. I think most other builders built with dry seams.

A copper rivet is a copper common nail with a burr driven over it (a copper washer that is properly called a "burr"). A "clench nail" is a copper nail that is driven through the lap and bent over and back into the plank in a "J" shape.
Some builders used just wood screws in the laps (Oldtown), and some used machine screws with nuts on the inside. I don't remember what Lyman used.