ocean cruisers made of plywood...

hi!

i would like to know what you think of ocean going cruisers (sloops with cutter-rig) in the length of 12-15 m (40-50 ft) made of fibre reinforced plywood...

i personally have absolutely no experiences whatsover with this material and would be thankful for any input on material characteristics, strength, thickness of construction and such...
if one could point out advantages and disadvantages it would be great...
or if it is just plain dumb and not adviseable as well...
thank's

 

There are many designs that could be made from ply, but I think that most of the advantages of ply are lost as the size goes up . If you interest is in a chine hull, then steel or aluminum make more sense IMO . If round hull , there must be some molded ply boats around . There was a boat called a Newporter 40 that was plywood sheathed in glass.
the keelson was made of laminated ply .

 

Have a look at www.yacht-design.nl/satellite. They have some very nice designs in plywood.

 

thanks for the info...

but i am actually not looking for a plywood yacht.. i am just curious about the material for the above mentioned purpose..

i know the advantages, disadvantages, the strength and the week points of steel, aluminium, wood, FRP in any kind or form and even ferrocement but just nothing about plywood constructions...

i know it is widely in use for smaller boats like dinghys of all shapes and sizes up to a certain length... the concept of using plywood for ocean going passagemakers is somewhat new to me and i am a curious person...
so i simply would like to know how this material is performing at a greater scale and if it is recommendable...

 

check these out

http://schooneribis.blogspot.com/search?updated-min=2007-01-01T00%3A00%3A00-05%3A00&updated-max=2008-01-01T00%3A00%3A00-05%3A00&max-results=4[/URL]

 

http://www.devlinboat.com/

 

check this multi chine ocean boat out

http://translate.google.com/translate?hl=en&sl=fr&u=http://fr.wikipedia.org/wiki/Pen_Duick&ei=jmvgSoWuG47ZlAfIhdSEDw&sa=X&oi=translate&resnum=2&ct=result&ved=0CBUQ7gEwAQ&prev=/search%3Fq%3Deric%2Btabarly%2Bpen%2Bduick%26hl%3Den%26safe%3Doff

http://commons.wikimedia.org/wiki/Fileen_Duick_II_%282%29.JPG

 

It is a good material. At that size it is still competitive in price and weight with metal boats.

 

A friend built a 37 footer out of hard chined plywood in the early 70's and cruised with his family around the Pacific for 7 years. The family are all now cruisers, so it couldn't have been too rough. The boat cost him $7,000 to build ,so it didn't owe him anything.

 

RM Yachts make production plywood, hardchine yachts: http://www.fastoceansailing.com/contenu/,home,1

Dudley Dix has some radius chine, plywood designs: http://www.dixdesign.com/radply.htm

 

how thick would the hull be for a 13,5 m or 45 ft yacht?
and what would be the kg per m² or lb/inch² if you prefer...
can this stuff take the load of a 3-4 ton keel at 2.0 m draft and how or what with do have to strengthen the keelson (is this the right word?)?

and thanks crag... because of the RM yachts i got actually very curious about this material...

 

The thickness of the hull depends on the framing system. The greater the frame spacing, the thicker the hull plating.

The ABS Offshore racing yachts rules include strength calculations for boats made out of plywood.

http://www.eagle.org/eagleExternalP.../Rules&Guides/Current/37_OffshoreRacingYachts

 

I would like to fully concur on that!
We have seen much larger boats made of ply. Though in my personal opinion somewhere in the mid 50ies metal becomes the more handsome choice.

Regards
Richard

 

Plywood is a wonderful material as long as it conforms to a standard such as BS1088,a boat built of ply is a different boat than one built of metal as it is possible to build very light in plywood.There are many,many plywood Searunner trimarans cruising the oceans of the world that are 30-40yrs old.John Spencer of New Zealand designed many larger plywood boats including the 69ft racing schooner "New World", the 73ft ocean racer "Buccaneer" and perhaps the most loved raceboat on the US west coast,The 2 times transpac winner 65ft ULDB "Ragtime" which last year at 42 yrs of age won the LA to Tahiti race,the coastal classic in NZ on IRC and the Sydney Hobart race on IRC.its a Great material.
Steve.

 

Yes, Rags has many miles on her now 45 year old plywood hull (launched 1964).

After sailing the Tahiti race, at time in nealy 40 knots of wind, she was cruised to NZ, raced in the area of her birth, sailed over to AUS, raced the Hobart, was shipped back to the US, and then sailed her 15th Transpac (that's 30 years of Transpacs), then was sailed back home from the Islands.

When you consider the current mast in Ragtime is probably more than 10 feet longer than the original, and the modern bulb keel is making much more righting moment, it is a tribute to her materials and construction that she is still stiff and fast.

A boat like Rags has been pushed much harder than any cruising boat would be, and the plywood material is still doing fine after nearly a half century of duty. Seems to me this is a good indication that a plywood cruising boat should be possible.