Hull Mold Construction


4.1 Mould


My mould started life as an Axeman 7 mould, however the bottom profile was altered considerable as describe earlier. In retrospect it would have been easier to start with a new mould as the side panels had warped over time and needed corrected. Live and learn!


The Geko hull has been designed so the mould can be easily made of sheet plywood bent over formers. Six formers, made of 12mm ply wood are spaced 559 mm apart. Remember to minus the thickness of the hull shell and the thickness of the mould skin from the offsets. The hull bottom and sides are flat. The formers are attached to the floor or another plank of wood to hold them firm. Ply wood or MDF, something around 10 mm, is bent around the formers. 

 Although the first Geko design has rounded corners i would advise for much sharper chines. Round the chines on the mould with a very small radius, approximately 2mm, so the carbon fabric can wrap around easily. Minimal filler is then needed for the corner when the foam is applied.

In the photo of the mould above you can see the the flanges that are necessary to produce a boat with flares. The Geko design doesn’t have flares so this flange is not needed. One of the hardest parts of building the Axeman 7 mould was cutting the sheets of ply in the long curves required to build the flares. 

To stop the laminate sticking cover the mould using brown parcel tape and covering film for books. The covering film is available from Woolworths. I’d advise you also apply some wax release agent. CFS fiberglass supplies sells release wax amongst other useful stuff. To seal the vacuum bag apply sealant tape around the edge of the mould. This is thick really sticky stuff, a bit like chewing gum.