[Public-list] careening ship

[Roger L Kingsland]

Thanks Don, good stuff.  If I have the hull blasted by others, laying the
hull over probably wont be that critical.  Even lazy me can operate a roller
upside down.

RE laying her over;  with nothing in the boat, the loads aren't
unmanageable.  I imagine she weighs around 7,500 pounds (no rig, engine,
tanks, hardware, beer, etc) and guess, because most of the keel load will be
carried there, the load on the hull will be less than 4,000 lbs.  One method
I thought of is to take a piece of 3/4" plywood and mount it on top of the
deck holding it down with blocks and clamps at the window openings  (I have
removed the toe rail).  I could then fasten say, 16-2x4 blocks on the
underside of the plywood against the rub rail (I have filled in the hull to
deck joint and there is solid epoxy under the rub rail).  This would create
250 pound loads 6" apart at the hull to deck joint, one of the stronger
areas of the boat.  I could then lower the boat and scribe and cut the other
end of the plywood so the entire length bears evenly on the concrete floor.
2x4s fastened to the plywood would keep it from buckling under load and the
base could be connected to the 2x10 on which the keel rests to prevent the
plywood from kicking out.  Lastly, I could reach behind my head with my left
hand and scratch my right ear.  All things considered, air bags seem allot
simpler.

Roger 148


----- Original Message ----- 
From: "Don Campbell" <dk.campbell at sympatico.ca>
To: "Alberg 30 Public List -- open to all" <public-list at alberg30.org>
Sent: Thursday, January 20, 2005 11:42 AM
Subject: Re: [Public-list] careening ship


> 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
>
>
>
> _______________________________________________
> Public-list mailing list
> Public-list at alberg30.org
> http://alberg30.org/mailman/listinfo/public-list
>
>



 1106242064.0