Several weeks ago, some of you expressed interest in the tow-plane I use. I finally remembered to take a couple of photos and I am posting them here!
The key thing with this rigging (and I figured this out after a couple of simpler versions...) is the moveable connection point for the towline, and simlarly, the adjustment for the seat cable length. (The ABS pipe is the seat...). By adjusting the point where the towline attaches, you can greatly reduce the effort needed to keep the board level. Otherwise, the board will have a tendency to pull up which gets really tiring...
Also, note the quick-release clip on the towline (with the orange lanyard). Sometimes, you just need to bail! (Approaching boulder, point of interest where you want to stop and have a look, or even simply ascending where you need to control your ascent rate.)
The size of the board itself doesn't really matter. This one is about 32 inches wide. The cut-outs are hand-holds, the D-rings are for attaching "stuff". I used to have a sheath knife bolted on, but took it off. Usually, I hook a spare computer through one of these.
Your boat driver needs to be very aware of diving. We plane at a max of about 4 mph. You will need a line that's at least two to three times your depth. I usually drag along in the 80 - 140 foot range! I suppose a spotter would be a good idea, much like water skiing, but since there's rarely any boats around us, it tends to just be us. If I release the line, it is very obvious on the boat as the drag drops suddenly. It's quite easy to cover long distances on one of these and it's great fun, but be careful. Depth can change very quickly and because your air will last a lot longer, you really need to keep an eye on your profile... And it can get especially cold due to the volume of water moving across you...
Incidently, for those of you in California, I have no idea what a Great White would think of this setup. "Trolling" comes to mind!
Hope this helps!