Have you looked at http://www.coolcats.com/windsurf/trailers/

I built one last year, using pine and plywood, just the box that is. Dimensions of box are 2800x900x600 mm sitting on a boat trailer chassis 4.6 m long. It added up to about $300 that's using cheap C/D ply and a reasonable grade pine. The box weights about 70kg and holds 3 boards, 5 sails, 2 booms, 2masts. My stuff packs tight in the box so I don't use racks, tie downs etc. I decided to go for compactness over some convenience.
Gross weight of rig is around 300kg.


How long is your box trailer, is it a 4'x6' one? I decided these are too short (if you want to put your boards in the box) because the centre of gravity of the trailer must stay in front of the axis ie. draw bar should weight atleast 30kg. Otherwise the trailer is very unstable and prone to sway and jacknife. So your box should not hang out back. I've seen someone with a tapered box that comes all the way up to the tow bar, ie a triangular box is built on the draw bar and a rectangular box on the "box".

Malcolm

contact RAL Innovations 03 54483965

specialist builders of ute trays, service bodies, trade toolboxes,
and custom trailers.

they will set you on the right path or do it for you.

best winds
Tony Lorenz

If anyone is interested, it is finished!!! I've put pictures up in the 'other' section of the photos page. See: www.seabreeze.com.au/gallery/ .

A 3m x 1.2m x 1.2m box that sits in a standard 6x4 box trailer. It can be hoisted up off the trailer (gear all still inside, singlehanded) and the trailer pulled out from underneath for when you need the box trailer as a box trailer.

Currently it holds three boards (including a formula board), but I've built it to have room for 4. Holds absolutely heaps of masts/sails/booms - as many as you'd care to carry. Overall internal length is about 305cm down the middle, so long enough to carry my formula sail (at 285cm), with the smaller sails laying towards the outside.

If anyone wants to try something similar, I can provide my plans for the box. Cost about $500 overall - $300 in plywood, and another $200 in miscellaneous screws, fittings, brackets, paint etc. The only thing I'd do different is make the base out of 17mm ply, instead of 12. Got about 40kg of downforce on the hitch so the balance worked out perfectly. Gotta say I'm pretty happy with it. No more guessing which board(s) to take!!