Welcome to the Heath Robinson School of Boat preparation. Firstly the Rib was lifted off the trailer using a combo of rope, ratchet straps and a barn roof. The whole issue then chocked up with logs and a trolly jack. Ant-fouling etc. carried out and boat dropped back on trailer. To add to the "Quad tow vehicle" thread. I'd be inclined agains't using one. This one is a big hefty farm model, but it didn't really like the weight of the Rib. I don't think that the auto clutch would put up with too much Rib manoevering.
