Why not use smaller cylindrical inflatable
bags under each hull
a vessel off the sand/beach. The cat. could then actually be moved backwards or forwards if needed to vary access for hull
processing, depending on keel
etc. configuration. I suspect the cost of say eight to ten of these cylinders would be less than the cost of a single
boat yard lift
out. OK. yes a small compressor
would be required although I have seen an arrangement for a small flatbed truck (called a "utility" in Aus.) that used the vehicle exhaust
(directly connected from the tailpipe to a bag under the flatbed.) The air bag (about 1 meter diameter) tilted the hinged trailer bed
that had a 3000 kg lump of concrete on board. Very impressive.
Any air bag arrangement would be easier on a hull than small area supports such as props or travel lift straps.
Incidentally, due to the beam of multihulls, the owner is often obliged to use and pay for very large travel lifts. In Cairns (Australia) this means that catamaran
lift outs are seriously extremely expensive.
Even if the lift out is done by a travel lift, the catamaran
could then be sat on the air cylinders to allow some movement backwards or forwards ... if needed.
The bags could be also used to achieve what is shown in the photo
. That is, just to lift the aft or possibly bow or even just one side of the catamaran.
I can see an innovative opportunity here for some manufacture. They could be marketed as "Republican air bags" or just "Trumps". My friend suggested a lot of inflatable
swimming pool lie-lows borrowed from the local kids
. He's a worry. But it does imply that such bags may well have other uses. Fenders, soft seats etc.