[Public-list] careening ship

[Don Campbell]

Roger
    There are heavy duty, paper covered plastic bags available to the trucking
industry that may be inflated to about 10 psi that are used  keep a load of boxes on
skids  in place in a trailer. They are about 5 or 6  feet long when not inflated. If
you really want to lay a boat over, then you might try these. They are about 30"
wide not inflated, so the area not inflated is about 1800 inches. If you use a
figure of 50% available area,  then 900 sq inches per bag, and at 9000 lbs that is
10 psi if you only use 1 bag. If you were to use 4 or 5 it should work well at 7 or
8 psi in the bags. The paper covering might be a pain to clean up but better than
the sand pile. I have seen these used by many shippers of fresh produce freight from
both California and Florida
    There is also the option of using  soda-blasting which uses baking soda to clean
the hull of bottom paint. This does not abraid the hull and may be used as one would
with sandblasting equipment, but only uses about 60 - 80 lbs per hour, much less
weight and volume than sand. You may have seen its use in building restoration work,
specially after fires. It is very easy to direct the flow of material to any surface
and takes about 2 hours to do an AL30 hull, which is much less exposure for you  to
whatever heavy metals are on the hull than any other non-abrasive removal system. As
for osmosis,  if there are any blisters, they will probably remain unbroken with
soda and you may then decide how best to attack whatever you need to in a very
localized way. Rolling on a barrier coat and finish coat is not difficult with the
boat upright except for the very bottom of the keel. I was able to lift the hull on
my trailer with the 8  pads,  so avoided that problem.  I have also been able to
take all the pads off one side of the hull at a time by adjusting the lean of the
hull and, for safety, tying the hull to either a large piece of equipment or the
wall of a building. Winches make it easy to exert force on the safety lines.
Don   #528




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