Trailer Design

Coldspring Paddling needs a kayak trailer so that I don't have to transport 5 kayaks at a time on top of my CRV like I did last week (too bad I didn't take a picture of that, but maybe it's better to avoid photographic evidence). I have a nice sized utility trailer that I want to extend the tongue of and add trees to. I've been playing around with Google Sketch-Up to design my modified trailer. What do you think of the design? It should be able to haul at least 8 kayaks (would do 6 nicely as illustrated), or 4 canoes, or 4 kayaks & 2 canoes, and so on. It shouldn't be overly heavy or tall. Plus, there's a fair bit of room for gear in the 4'x6' box. Now, hopefully I can get Rod's help to build it!

Update (27/5/2011): My trailer is at a local welding shop for the modifications. He suggested stiffening the long tongue with a brace that goes upward from the tongue to the top of the trailer box. Also reinforcements are needed where the trees will bolt on to the trailer box. The trees will be removable, bolting into a socket that remains in the trailer box. Also, for simplicity, only one upright will be used for each tree (not two as illustrated), but with the cross bar joints strengthend with a triangular piece of metal welded in at the joint.