That trailer could be a good investment. If the deal doesn't happen you can re-sell it.
Perhaps you could rent a (BIG) floor-standing engine crane to do the transfer. Not having to buy the steel, welding, etc. would pay for the rental. If the seller "gets" to keep his wonderful trailer he might lower the price on the boat a bit more. (This from one Scot to another ;))
Seems like a lot of this is the seller's problem but that's just me.
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