<font color='black' size='3' face='Arial, Helvetica, sans-serif'><font class="Apple-style-span" size="3">Jon and all,</font>
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<div><font class="Apple-style-span" size="3">As to replacement, I'm planning to carry a spare, rigged out and ready to go. Any sign of failure and I change it out with the back up, then the replaced thruster goes into overhaul. As Jon says, $250 bucks is cheap insurance, and carrying the extra means an hour's work to save a long-planned dive week-end from ruin by a failed o-ring.</font></div>
<div><font class="Apple-style-span" size="3"><br>
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<div><font class="Apple-style-span" size="3">Vance<br>
</font><br>
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<div style="font-family: helvetica, arial; font-size: 10pt; color: black; ">-----Original Message-----<br>
From: Jon Wallace via Personal_Submersibles <personal_submersibles@psubs.org><br>
To: Personal Submersibles General Discussion <personal_submersibles@psubs.org><br>
Sent: Sun, Jul 27, 2014 9:44 am<br>
Subject: Re: [PSUBS-MAILIST] Air compensating thrusters<br>
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Alan,<br>
<br>
Everyone is correct...about their own experience. This is a Ford
vs Chevy debate with neither system being a perfect solution.
Primary use is likely going to dictate the best path to take, air
comp if you can't sacrifice power reduction or risk brush issues
in commercial operations, oil comp for simplicity in recreational
operations.<br>
<br>
Alec's experience is a pretty good story for recreational diving.
A 10 year life prorates to a cost of only $25/year for each MK101
and from a performance perspective he can't tell the difference
between air/oil comp on a small minn-kota. JimK's 7-ton Bionic
Guppy gets muscled around easily with three oil comp'd MK 101's so
they obviously have plenty of power even if its less than it would
be with air comp. That's enough evidence for me...no regulators,
no extra gas to carry, no extra plumbing, no overpressure valves
and no worries about maintenance or failure on all those small air
compensated components. At $255 for a MK101 lower unit, I'll just
create a replace-one-motor-a-year budget. No need to open the
can, replace brushes, turn the armature; just replace it with a
new one and I'll never have one motor that is more than four years
old.<br>
<br>
So you probably just want to toss a coin and pick a method. Maybe
start with air comp first on a new build because if you don't like
it then converting to oil comp will potentially be easier than
vice-versa.<br>
<br>
Jon<br>
<br>
<br>
On 7/27/2014 3:42 AM, Alan James via Personal_Submersibles wrote:<br>
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<div><span>Thanks Alec,</span></div>
<div style="color: rgb(0, 0, 0); font-size: 13px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; font-style: normal; background-color: transparent;"><span>I was intending to also mention your
experience as a balance to the negatives</span></div>
<div style="color: rgb(0, 0, 0); font-size: 13px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; font-style: normal; background-color: transparent;"><span>but got distracted.</span></div>
<div style="color: rgb(0, 0, 0); font-size: 13px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; font-style: normal; background-color: transparent;"><span>The problem is that I am hearing a lot of
conflicting stories.</span></div>
<div style="color: rgb(0, 0, 0); font-size: 13px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; font-style: normal; background-color: transparent;"><span style="background-color: transparent;">Even
with air compensation there are problems. Greg told me he
had a problem</span><br>
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<div style="color: rgb(0, 0, 0); font-size: 13px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; font-style: normal; background-color: transparent;"><span>with moisture getting in through the
exhaust valves of a second stage regulators.</span></div>
<div style="color: rgb(0, 0, 0); font-size: 13px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; font-style: normal; background-color: transparent;"><span>I have put extension tubes around the
exhaust manifolods of my ambient sub's compensating</span></div>
<div style="color: rgb(0, 0, 0); font-size: 13px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; font-style: normal; background-color: transparent;"><span>regulators to try & stop this.</span></div>
<div style="color: rgb(0, 0, 0); font-size: 13px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; font-style: normal; background-color: transparent;"><span>I dive mostly in sea water, which is not
as forgiving as fresh, so want to get it right.</span></div>
<div style="color: rgb(0, 0, 0); font-size: 13px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; font-style: normal; background-color: transparent;"><span>Emile was telling me about repeated
problems with one of his sub's thrusters, & he is now
using</span></div>
<div style="color: rgb(0, 0, 0); font-size: 13px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; font-style: normal; background-color: transparent;"><span>expensive rim thrusters. I will </span><span style="background-color: transparent;">leave it up to him if
he feels like sharing the details.</span></div>
<div style="color: rgb(0, 0, 0); font-size: 13px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; font-style: normal; background-color: transparent;"><span>The guys at Fugu sub with 30 years
commercial experience are saying go with air, there are too
many hasles with oil. All commercial oil compensating units
have about 5psi overpressure which your system </span><span style="background-color: transparent;">doesn't have. So who
is right? </span></div>
<div style="color: rgb(0, 0, 0); font-size: 13px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; font-style: normal; background-color: transparent;"><span>Cheers Alan</span></div>
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