Re: [PSUBS-MAILIST] Hydraulic Drive Unit

["Walter Starck" <wstarck@ozemail.com.au>]

Some further comments on responses to my comments on this topic.

Gary Boucher wrote: " I get somewhat irritated when people that have not
gone through this
process sit back like armchair quarterbacks and make broad reaching
technical statements."

I do too but with over 40 years experience in designing, building,
operating and maintaining a wide variety of underwater and marine
equipment I have gone through the process.
---
Alec Smythe Wrote: "In an earlier post Gary pointed out that in
hindsight, he recommends compensated trolling motors for their
simplicity."

This seems to agree completely with what I have said although Gary now
seems to disagree.
---
J. Barlow wrote: " Electrical thru bulkhead connections are expensive,
difficult to find, larger, and more prone to leakage."

It is very easy to make extremely reliable ones using modified flare
fittings.  Use of the right type of cable is important as well.
----
Sean Stevenson wrote: "For the homebuilder, overcoming the efficiency
issue is the only real hurdle
for emplying a hydraulic system."

This like saying overcoming gravity is the only real hurdle to building
a flying saucer.  High friction losses are inherent in hydraulics.  For
brief or intermittent operation or anywhere power is not limited this
loss may not be important.  In small submersibles however, available
power is a limiting factor and taking a 30% or more efficiency hit on
usage is an important consideration.
----
Carsten Standfuss obviously understands the issues.

Walter Starck
Golden Dolphin Video CD Magazine
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