test fitting the box & lid onto the trailer

4 over-centre catches will hold the lid down tight and its come up that well I'd say it would be very simple to completely seal it up with a thin weather strip






The lid can be easily removed when the boat is on the trailer either from the back or from the front.
The box size is 400mm wide, 170mm high and 3100 long, the lid is 450mm wide and has a 50mm lip that hangs down past the top of the box, the height of the lid is only 75mm and its length is 3180mm
All up cost was around the $200 mark, that includes rivets, silicone, catches etc etc ..... and an enjoyable Saturday afternoon folding up the ends and fitting it all together.

The reason I went this way over a fibreglass coffin is simple.... the "head room" between the trailer chassis and the dolphin striker is only ~200mm, there was simply no way I could squeeze in an off the shelf glass coffin in the room I had.....

The other reason for its size was also simple.....
the boom, centre-boards, rudders and cases, along with the mainsail and jib all fit easily, there's enough room left for 4 life-jackets, a couple of trap-jackets and 4 wetsuits, (obviously once all dried), so it also acts as a storage cabinet for the times the boat is not in use.