Seabbatical's D55 "DRUA"

There isn't a lot of information available about the evolution of multihulls in ancient Polynesia.  The book Canoes of Oceania seems to be the bible.  It says that the Figian double canoe (Ndrua) was the largest and finest sea-going vessel ever designed and built by natives of Oceania before contact with Europeans.  Boats of over 100ft were constructed and sailed the Pacific. About the time of Captain Cooks second and third voyage of discovery (about 1773) he noted that most of the catamarans had been replaced with the Drua style of Fiji.  Also called the Alia in Samoa and the Kalia in Tonga. I believe it was the highest development of the sailing multihull in Oceania.  I think we will see a return of these boats in the future.

Below and in the image gallery are photos of the Seabbatical Drua commencement of construction with the cutting of the foam for the hulls. Check back often as the build goes forward in Peru


I think it was Dick Newick who said that you can have a fast boat, a cheap boat and a spacious boat but you can only have two out of the three.  I decided that we would pursue the ancient Ndrua to make a boat that hopefully gets us a little further down the curve in terms of a faster boat with more volume for a reasonable price.

From an engineering perspective there are many advantages to this type of boat.  You can carry more of the cruising payload, tanks, batteries, motors to windward and that lets you have more righting moment and allows you to carry more sail area for a given displacement.  For very little extra cost you can stretch out the Leeward hull.  This quickly drops the Displacement Length for the boat and gives performance and comfortable ride of an equivalent length catamaran.  But the catamaran needs two long hulls.  It needs stronger beams connecting them because you will have higher torsional loads.  Designing a boat that sails in both directions also adds some complexity.  But I think we have found eloquent solutions to these challenges. 

I hope you follow the design and build process of the Seabbatical 16.  I think you will find it interesting.  Many of the new cats talk about how revolutionary there new concept is.  After reading everything you wonder what is new about it.  I think our project to build the first commercial cruising proa is quite unique.  Right now the material to build the shell is 80% of that required to build a 39 ft catamaran.  But we are building a 16M or 52 ft boat with 24 ft beam only 2 ft draft and about 7 tons displacement.  It should have more accommodation than a 42 ft cat with 4 queen berths in the hulls and room in the saloon for 4 - 6 kids to sleep.  The performance should be equivalent to a 52 ft cat.  We are using a modular build process which is very similar to the Ndrua.  We will build the hulls fit them out then put the entire central unit on top of the hulls.  This allows us to finish the hulls and central unit at ground level and not have to climb in and out of the boat with each item.  We are using a Biplane rig with a mainsail in each hull.  We will have two boards but they will also be able to steer so they will act as rudders also.  Our ultimate goal is to make a boat that will not cost as much to maintain.  This will be the real measure of worth in my books.

 

Happy Cruising

Ron Bokenfohr
Seabbatical Modern Ocean Voyaging.

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