Wednesday, November 3, 2010

Building a Hull of my Gypsy Catamaran

After the 4 pieces of foam composite panels were constructed it is now time to assemble the pieces together to form one hull. First I have to find some timber to become the base of the bulkheads. Someone was demolishing a wooden house and I bought 4 pieces of 2 by 6 quite cheaply from him.

The spacings for the bulkheads are marked as per the plans. Wooden blocks are placed at the correct stations . Bulheads 4 and 5 were the first to be installed. The bulkheads are built from BS 1088 export quality Meranti marine plywood. A sprit level gauge is used to ensure that the bulkheads are perpendicular.A thread through a hole at the half width waterline of all the bulkheads are used to judge the levels/bulkhead heights. All the figures are given in the plan.I only have to use my physical strength to position the bulkheads. 2 by 1 woods are used to raise the bulkheads. Chipboard backbones are then made to provide some temporary structural strength and later to ensure the hull bottom is flat when it is offered to the hulls.These chipboards are removed when the hull is ready. A lot of "heavy" physical work is involved at thsi stage so I got hold of a local fisherman Yee to assist when he is not at sea.The backbone goes all the way to the transom.The first composite flat panel is then brought in. It need 3 person to put it in position. This is not so much of a weight problem but more of a size proble. Wooden stilts from 2 by 1 wood are used to support the panels. The panel is clammed onto the wood. Final position adjustments of the panel are made.The panel is then secured to the bulheads by screwing the panel into temporary wooden blocks.The second panel is then brought in and the same process is then repeated.
The initial use of F clamps make the job of fine adjustment of the panel position easier.The bow of the hull is then "forced" together using long clamps and twisting wires. At this stage the shape of the hull is formed. I cannot stop admiring the beautiful shape!The bow is glassed in stages so thet the wires can be removed one at a time.Next the bottom panel is positioned at the top of this inverted hull. Heavy objects like bricks and stones are used to ensure a flat bottom and not an "S" shaped bottom!The most difficult part is building the bow and getting the correct shape. A sort of stich and glue method is used. Next will be the fairing and painting of the hull before turning over '


  1. I like your building technique ,.....using fiberglass panels is really a good idea,I believe Richard did this as well,looks very good....Jim/Bat/CanuckEclipse...;0)

  2. yea.. i agree, looks easier...

  3. Mr Wong,

    Please update your project pictures. We are waiting....