We really do need a small crane to move our Viking ships off and onto lorries, trailers etc. It doesn't need to be huge and would need to lift no more than three tonnes. What I had in mind was something like an engine crane rit large.
What sort of reach does it need to have? I'd imagine quite a bit, and that will probably impact things a lot - the boom will need to be substantial, which means quite a big truck, significant stabilisers etc.
What about drop - does the transport truck always sit on dry land with only a foot or two to the water, or are you sometimes dropping things many feet over the side of a dock / pier etc.? (If the drop's always quite small, I was just thinknig that something with a hydraulic lift, but not necessarily a crane, might do the job instead)
Do you expect to take the crane with you on the transport truck, or does it need to be self-propelled? If the latter, what sort of distances does it need to travel?
Would the boat be lifted from above using flat web straps, or with it sat on a cradle? If you use straps transversely under the keel you will need to use a spreader beam across each to prevent the weight of the boat crushing the gunwales inwards, and probably two to keep them from sliding together longitudinally. Unfortunately, all this adds weight and height when they all meet at the apex.
What are the boats dimensions? Would they fit on a =93Roll-on =96 Roll-off=94 demountable plant flatbed?.
In a previous working life during the early the eighties I was seconded to drive the company 15 ton RT mobile crane, and their 22 ton Rusting Buggybus rigged as a crane, when required. I launched two boats of a similar weight lifted from trailers, and one vice versa (*), using a spreader frame.
(*) Sorry, I can=92t think of a single word for the opposite of =93launch=94 ?
Sorry about the last message but, out of the blue google swapped all its threads from our normal account (on yahoo) to the one the wife has to have on Gmail to access some of the stuff that outlook express used to handle but windows 7 does not. Blooding computer programmers!