WWII brought about many advances in waterproof glues for use in the aircraft industry.
It is interesting that this change appears to have started before the Second World War. The transition of canoe builders like Rushton from lapstrake to wood/canvas in the late 1800s and early 1900s was more obviously driven by economics. It is less clear why the market shifted back to lapstrake construction in the late 1950s and early 1960s when this is usually a more expensive way to build a boat than the wood/canvas and all wood techniques that had been in common use for many years before then. Let me offer some examples.
Old Town introduced an open 14 foot long lapstrake boat in 1932 and a 15 foot version with a long deck in 1941. Similar and larger versions of these boats remained in their catalogs until 1966. They introduced a 16 foot long canvas covered boat in 1928 that lasted until 1941. Their all wood version of this boat was in the catalogs from 1929 to 1957. I am less familar with the other builders but the following is a brief summary from what I've found in a quick review.
E. M. White added a canvas covered outboard boat in their 1923 catalog wihch lasted until their circa 1953 catalog. Their "Lapstrake Clippper" arrived in the circa 1940 catalog and similar boats remained until their 1962 catalog. They don't appear to have ever offered a smooth sided, all wood boat.
Thompson appears to have offered all wood "strip-built" boats from 1926 to 1956. Their canvas covered runabout was offered from 1932 to 1943 and the lapstrake "clinker sea skiff" model was offered from 1937 to 1961.
The circa 1926 Penn Yan catalog indicates that they were building all canvas covered "composite construction" boats and their 1933 one adds all wood or "Monowood" ones. Their lapstrake "Clinker model" appears in 1958.
There just doesn't seem to be a simple economic or other explanation for why all of these builders and others abandoned their existing boat building techniques to go back to lapstrake construction in a big way during the 1940s and 1950s. It appears that many of the outboard motor boat buyers in the mid-1900s liked lapstrakes and were willing to pay a premium for them. The interesting part is that most of the canoe buyers in the early 1900s faced the same decision and disagreed. It could be because the "lapstrake planing hull has a small advantage over a smooth bottom hull for racing on flat water. It is able to break the large surface adhesion into smaller areas" as described at
http://books.google.com/books?id=5g...=onepage&q=royces motor boat ourboard&f=false on page 49 of "Royce's Powerboating Illustrated" by Patrick M. Royce. The ability to "twist and flex" as described at
http://en.wikipedia.org/wiki/Clinker_(boat_building) in Wikipedia may also have been a factor along with many of the other advantages mentioned here previously. Interesing stuff,
Benson
