<font color='black' size='3' face='Arial, Helvetica, sans-serif'><font class="Apple-style-span" size="3">Hank,</font>
<div><font class="Apple-style-span" size="3"><br>
</font></div>
<div><font class="Apple-style-span" size="3">Harbor Branch used o-rings on the reduced output 1 1/4 thrusters on the JSLs. The mid-body on the hard can (actually the back 25% or so of the cylinder section) was machined on the output side for planetary gears, and machined on the motor side to replace the entire output plate/bearing case for the motor itself (like a golf cart motor bolts into a differential). Pretty nice and compact for the day.</font></div>
<div><font class="Apple-style-span" size="3"><br>
</font></div>
<div><font class="Apple-style-span" size="3">The rear section of the hard can behind the gear case is a hollow sand casting shaped like the long end of an egg, webbed internally to support a 1" shaft, double bearings, with double thrust bearings, and a tapered, polished, hardened aluminum sleeve pressed in from the pressure side.</font></div>
<div><font class="Apple-style-span" size="3"><br>
</font></div>
<div><font class="Apple-style-span" size="3">The shaft itself was machined to carry double o-rings in square cross section grooves and terminated on the internal end with a flex-coupling which mated (obviously) to the output of the planetary output. A big shaft was necessary to keep the jitters down to more or less zero. Everything needs to stay exactly centered, as the O-rings will go to pot a whole lot faster if there is any flex or vibration at all in that prop shaft shaft.</font></div>
<div><font class="Apple-style-span" size="3"><br>
</font></div>
<div><font class="Apple-style-span" size="3">Lots of development to get it right, finally, but the props turned about 275-300 rpm (I don't remember exactly, but something like that). 14" X 14" Kort style prop in a machined syntactic foam nozzle supported on a 4-legged frame welded to the aft part of the shell. I actually have a blueprint of it, somewhere around here. For those interested, the tip clearance between blade end and nozzle sleeve was about 50-thousandths. NOTE: That would be of an inch, Emile.</font></div>
<div><font class="Apple-style-span" size="3"><br>
</font></div>
<div><font class="Apple-style-span" size="3">There were no speed controls on the boats. Fwd-Off-Rev only. You just turned thrusters on or off to vary the push. When I was there, we had 5 for forward and reverse (3 in a row on the centerline with 1 each to port and starboard aft) plus a vertical and horizontal pair forward and aft for steering and fine maneuvering (fine maneuvering my ass!!!). That's right. NINE thrusters that probably with cabling weighed over half a ton. Plus two or three spares in the kit ready to bolt up at a moment's notice as replacements. We were definitely in the motor business with those babies.</font></div>
<div><font class="Apple-style-span" size="3"><br>
</font></div>
<div><font class="Apple-style-span" size="3">They were home grown but worked reasonably well, although they were a little noisy with the gear case and whatnot. That said, I never saw the electrical side flooded on one of those things. Not once. Ever. We had a routine service schedule and changed a thruster every so many hours of service. Just put a fresh one on (two people could do a change-out in about three minutes), then tear the to-be-serviced unit down to check brushes and bearing lube and change the shaft o-rings (which would be looking a little fuzzy by then, but still worked fine--and even if they looked brand new, we changed them). It needs a really, really first rate waterproof lubricant, as the internal shaft o-ring runs hotter than the one in contact with the water, and was often in worse shape than the one primary as a result.</font></div>
<div><font class="Apple-style-span" size="3"><br>
</font></div>
<div><font class="Apple-style-span" size="3">Once the JSLs re-certified to 3000 feet, engineering redesigned the seals for better service, using a ceramic cartridge seal in place of the o-rings, but that was after my day. </font><span class="Apple-style-span" style="font-size: medium; ">I'd hate to even think what one would cost today, built commercially. You wouldn't use them, probably, as a unit with twice that power is probably a third the size and weight.</span></div>
<div><span class="Apple-style-span" style="font-size: medium; "><br>
</span></div>
<div><span class="Apple-style-span" style="font-size: medium; ">Those thrusters on the Tritons, for instance, look positively tiny by comparison, and they're rated at over 2 hp. Then there's our own Uncle Dr. Phil's new mag coupled ones. Now there's a Christmas present to ask Santa for.</span></div>
<div><span class="Apple-style-span" style="font-size: medium; "><br>
</span></div>
<div><span class="Apple-style-span" style="font-size: medium; ">All that aside, the o-rings will work if you plan regular service (ie, scheduled o-ring replacement) and don't wait for water intrusion. They have to be done right during construction, though. Those surfaces have to be mirror smooth.</span></div>
<div><font class="Apple-style-span" size="3"><br>
</font></div>
<div><font class="Apple-style-span" size="3">Vance<br>
</font><br>
<br>
<div style="font-family: helvetica, arial; font-size: 10pt; color: black; ">-----Original Message-----<br>
From: hank pronk via Personal_Submersibles <personal_submersibles@psubs.org><br>
To: Personal Submersibles General Discussion <personal_submersibles@psubs.org><br>
Sent: Sun, Sep 7, 2014 4:51 pm<br>
Subject: Re: [PSUBS-MAILIST] Brushless Thrusters<br>
<br>
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<pre style="font-size: 9pt;"><tt>
Brian,
Vance would know better than me, but I think if you keep the rpm under 1,000 you
can use an o ring for a seal. I thought Perry did that in the early subs to
1,000 feet.
Hank--------------------------------------------
On Sun, 9/7/14, hank pronk via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>>
wrote:
Subject: Re: [PSUBS-MAILIST] Brushless Thrusters
To: "Personal Submersibles General Discussion" <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>>
Received: Sunday, September 7, 2014, 4:42 PM
Brian,
You can use a simple
mechanical seal, that is what the K subs have. An 891
Chesterton mechanical seal is good fo 600 psi, that is what
Gamma had when I got it. You can buy them on ebay for 100
bucks. Build the shaft to fit the seal, and your
sailing.
Hank--------------------------------------------
On Sun, 9/7/14, Brian Cox via
Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>>
wrote:
Subject: Re:
[PSUBS-MAILIST] Brushless Thrusters
To:
"Personal Submersibles General Discussion" <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>>
Received: Sunday, September 7, 2014, 4:29
PM
I
talked to a hydraulics guy a few days ago about making a
seal for my motor pod. I told him I had a
high pressure
tank that I wanted to turn a
shaft inside the tank to stir
the contents
at 250 psi, ( didn't want his eyes to
glaze over if I mentioned submarine !) Anyway he
directed
me to a system using a bronze
fitting that would tighten
down these rings
he called "cheverons" they are
mating rings of a very high durometer . the bronze is
for
mating with stainless . I would have
to machine an
assembly for this , but once
I have my shaft size (1 inch
most likely) I
will be able to size everything
accordingly. Brian
---
<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>
wrote:
From: hank pronk
via Personal_Submersibles
<<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>>
To:
<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>
Subject: Re:
[PSUBS-MAILIST]
Brushless Thrusters
Date:
Sun, 7 Sep 2014 07:07:20 -0700
Alan
When I upgraded the
cartridge seal in Gamma, I needed a pretty
Beafy thrust
bearing, it was no problem to
get. have since changer to
Magnetic. I think you could replace the bushing
in a
thruster with a ball bearing and never
look back.
Hank
From:
Alan via Personal_Submersibles
<<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>>;
To:
Personal Submersibles General
Discussion <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>>;
Subject:
Re: [PSUBS-MAILIST] Brushless
Thrusters
Sent:
Sun, Sep 7, 2014 1:43:49 PM
Hi Hank,the kort
nozzle on the Indonesian thruster looks a bit
Naff. ( I am designing an art work
here.)I could get a price for the unit
without
kort nozzle, butI'm wondering
if I could
build something for 1/2 that
price.There are some
reasonably priced
brushless motors about.I
don't know
that I could just retro fit a thrust bearing
inside the can of the motor.I tried to put
a
thrust bearing for reverse inside my
brushed thrusters,
butcouldn't find one
with a thin enough
section to fit.Also the
motors are a bit
expensive to just buy
& hope you can fit
one.How did you fit
the thrust bearing on Gamma?
Did the
propellor shaft extend out the backof
the
motor?Alan
Sent from my
iPad
On 7/09/2014, at 7:22 pm, hank pronk
via
Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>>
wrote:
Allan
Dont
worry about
thrust bearings to much. They are aesy to get,
I bought one for Gamma , real heavy duty for
80 dollars.
Personally I would just use a
good quality bearing and
replace it once a
year for 8 bucks, if it is a small
thruster. Are you not happy with the
Indonesia thrusters?
Or to pricey?
Hank
From:
Alan via
Personal_Submersibles
<<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>>;
To:
Personal Submersibles
General
Discussion <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>>;
Subject:
[PSUBS-MAILIST] Brushless
Thrusters
Sent:
Sun, Sep 7, 2014 11:58:56 AM
Hi people,
I've
spent several hours today looking at brushless
thrusters
& wonder if anyone else has
looked at them or got any
ideas. There is
the Indonesian thruster I posted a few weeks
back at US 2,200. There is also the Haswing
Protruar 2hp
that Emile has; however they
state that it's for fresh
water only,
& I think Emile said it was a bit noisy.
The inrunner motors that have the winding
on
the outside, seem a good option as they
cool through
convection to the can. They
also need higher revs for torque
&
require a planetary gear box or similar. ( which a lot
have built in)
I was
looking at the
option of making my own
thruster, however the motor would
require a
thrust bearing & I don't
know of
any that would have one other than
maybe
a high powered battery operated drill.
Any
thoughts, suggestions thanks.
Alan
Sent from
my
iPad
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