Many thanks for all the kind words. I don't know the weight for sure, but I can easily lift one end up with one hand. I lifted the whole hull, single handed, from the trailer on to a couple of saw horses yesterday and it was no effort. My guess is that the hull as it stands probably weighs about as much as a big canoe.
Here are a couple of the latest pictures of the drive unit. First, the power head, with the TowerPro outrunner, belt reduction drive and modified 6 FET controller:
The 1" stainless tube that contains the drive shaft goes through an O ring seal inside the machined alloy block to the right of the photo and the diecast alloy box that the whole unit is in is sealed to IP66, so I'm confident that it'll cope with working in a damp environment. This unit is actually fitted inside a watertight compartment in the stern of the boat, so it should stay pretty dry, but I've learned over the years that water gets pretty much everywhere on board a boat!
The underwater drive part, using the double universal joint system, looks like this:
The 1" stainless tube fits inside a bearing tube that is sealed but which allows the unit to be rotated to steer the boat. The prop that is going on this is the stainless steel folding one that I've shown earlier in this thread.
The UJ has the advantage of absorbing very little power. My total losses (electrical and mechanical) at full throttle, running in air with no prop fitted to the shaft, are just 12 watts. The controller accounts for about 1 watt, the motor losses are about 5 watts, the belt drive absorbs about 3 watts so I'm losing about 3 watts in the bearings, universal joint and prop shaft seal. I know that the seal is absorbing around 2 watts, so that means that the bearings and universal joint are only soaking up around 1 watt - pretty good when compared to a right angle gearbox and it runs silently.
Please ask questions on the forum, rather than by PM, as it helps others and you'll get a better range of answers.