August 2003

As the bow is likely to take the brunt of any head-on impact I thought Id use some heavier duty T-section to brace the front of the hull, linking the inner frame, the outer frame, the floor, the front deck, the bow planing panel and the front of the cockpit. I could probably have bought a heavier T-section extrusion, but as I had plenty of 50mm x 4mm strip, I welded up my own T-section and then welded a triangle of this into the frame. This heavy T-triangle will also carry the load from the towing eye which sticks up from the bow deck.

The towing eye is for winching the hovercraft onto the trailer, and even for recovery if I ever break down on water (surely not!).
 

Bow planing section
The bow planing surface was difficult - due to the size of the panel (it only just fitted into a 2m x 1m sheet) and the complicated shape that was needed. I decided to cut out a cardboard template to get the shape right, then transfer this shape onto a sheet of aluminium. The card was not well supported by the aluminium frame and this was tricky, but it did give a reasonable pattern. I cut out the bow section panel with the jigsaw, fitted it to the frame, and then trimmed it in-situ to give the 1 or 2mm accuracy needed at the edges, where they butt up to the ends of the side planing panels.

More welding
The deck support strips were only welded to the frame tubing on one side of the strip the opposite side to the panel. I decided that in the areas where the T-pieces meet the frame I would weld both sides of the strip (i.e. top and bottom) to the side of the tube for extra strength. This meant a bit of tidying up the weld with the angle grinder to allow the deck panel to sit nicely, but it was probably worth it.

Having done quite a lot of welding to get to this stage, I then found that the holes in the floor were no longer in the right place to line up with the sides of the craft. This is probably down to some or all of the following:

The Hovercraft does not sit on a perfectly flat surface (the garage floor), so it must twist a bit at least.

The welding warps the metal a little.

Welding closes up gaps.

Either way, I welded-up the front holes in the floor panel and re-drilled them to allow the floor to be screwed to the front curved angle joint which forms teh cockpit front.
 

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