Re: [PSUBS-MAILIST] Sub with arm

[Stan Muller <smuller@iland.net>]

Hi Dan H.
   I had thought about the need for a stable platform from which to work
with the arm. This is the reason my arm will be mounted on the side of
the sub, below the conning tower. Set up this way, the mass of the hull
and tower will help prevent the boat from moving when a force is applied
to the arm. Initially I had thought to put it on the bow, but was
concerned about the torque applied to the arm moving the boat.
   > but than I have done some back yard,
> picnic table, fish pond engineering myself a few times.
   One thing I have found to be common among the backyard shade tree
engineering types, Is they, as a group, tend to over engineer, usually
ending up with a 300 % or better fudge factor. As the case in point, my
hull; The tanks are 1/8th inch aluminum, I don't know what they were
built for, but they have the manufacture ID tags on them showing that
they were pressure tested to 175 lb per sq. in. over which I will lay a
minimum of 1/2 inch of epoxyed fiberglass, (woven), and laid on the bias
of each preceding layer. Since the deepest dive we can make in our local
lake is 45 feet, and our operating depth will be no more than twenty
feet, my buddy and partner in crime, made the suggestion that we use my
two cylinder vacuum pump to draw a vacuum inside the hull of twenty to
twenty five inches while the sub is down there. I am sure this is
overkill, but that is what makes empirical engineering such fun. ;-)
Just think of the bang and the fish kill if it implodes. ;-)

Hi Phil,
   Your arm, is just what I am trying to accomplish. My reason for going
the hydraulic route instead of the air was to have more control than the
on / off of an air set up. I will, however, incorporate the  weight
reduction holes in mine, just so it will look cool.
> The air manip worked well, could easily attach a lift line to an outboard,
> collect specimens into a screen tray, retrieve small object s directly,
> etc.
   This is exactly what I plan on doing with mine, plus some sampling
functions. Did you use the same "hand" for all your applications? I
found it easier to have a "change hands" ability for different jobs
rather than try to design one to do it all.

Thank you, one and all, for your assistance, Stan, the shade tree
mechanic that has survived, 'cause he's chicken!