Cliff, In my humble opinion stick with Electric thrusters as
the Comsub has Hydraulics and the hydraulic pump is damned noisy. Gear pumps cheapest
but worst, Vane pumps next cheapest and a bit quieter but piston pumps are the
quietest but most expensive. Also ROV’s have unlimited power. Next mission I
am trying to work out how to isolate the pump and noise. Parker have a “silencer”
I may try. Already it is on vibration mounts etc but I think that it is going
to drive me nuts. ROV’s don’t have listening devices such as ears. For ROV’s
hydraulics are understandably a great solution but you are going to need a big
Amp to use David’s hydrophones! Cheers, Hugh
From:
owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org]
On Behalf Of Sean T. Stevenson
Sent: Wednesday, 21 October 2009 9:17 a.m.
To: personal_submersibles@psubs.org
Subject: Re: Re: [PSUBS-MAILIST] Surplus Thrusters?
Cliff, without exception, every large ROV I have worked on has used
hydraulic thrusters. What sort of power do you have available? If
you can handle the noise and the power draw, this might be the easiest way to
home build a high power thruster - just an off-the-shelf motor, prop and
shroud. As long as you can cool the oil, you can operate at 100% duty
cycle between PMs.
-Sean
On Oct 20, 2009, Cliff Redus
<cliffordredus@sbcglobal.net> wrote:
Greg,
I am not knocking the Minn Kota's. If I can not find used commercial
grade thrusters at a reasonable price, I will go with Minn Kota's.
Commercial grade thrusters are design from the ground up to be thrusters.
The biggest market for thrusters is the ROV industry. In the area I work
which is off shore oil and gas , day rates for deepwater drilling rigs can
run over $400,000 per day. When a ROV goes into water, it has work or it
cost the operator big time. So thrusters on these units are heavy duty
and very reliable as a rule. Also there is the issue of duty cycle.
Commercial thrusters are meant to operate many hours a stretch on a day in and
day out basis. These points imply to me at least that commercial
thrusters are probably more reliable than a converted boat trolling
motor. Reliability does not come cheap. I got a quote on some
Tecnadyne thrusters. For thrust on the order of 60 lbs, your talking
$8000 per thruster. This does include the cost of the control
electronics.
Cliff
Cliff Redus
Redus Engineering
USA Office: 830-663-6445
USA mobile: 830-931-1280
cliffordredus@sbcglobal.com
From: "Gregory B.
Snyder, MD" <greg@snyderemail.com>
To: personal_submersibles@psubs.org
Sent:
Tuesday, October 20, 2009 1:56:03 PM
Subject:
Re: [PSUBS-MAILIST] Surplus Thrusters?
Hi Cliff
I am curious, has there been a reliability issue with Minnekota? Thanks
Greg
Gregory B. Snyder, MD
Date: Tue, 20 Oct 2009 10:47:11 -0700 (PDT)
Subject: Re: [PSUBS-MAILIST] Surplus
Thrusters?
I am looking
for four surplus/used thrusters for my next boat, two at around 100 lbf
thrust and two around 50 lbs. The depth rating is 1000 fsw. While
most psubs go with pressure compensated Minn Kota trolling motors I am
looking for some used commercial thrusters to improve reliability.
If anyone has some thrusters they would be willing to part with and know of a
source, let me know.
Cliff
R
From: Jay K. Jeffries
<bottomgun@mindspring.com>
To: personal_submersibles@psubs.org
Sent:
Monday, October 19, 2009 9:24:25 PM
Subject:
RE: [PSUBS-MAILIST] Continuing saga of homebrewed Chinese sub
Frank,
I tried capturing it but had no luck with the various
different programs that I hold. Agree that it would be good to have a
copy for future purposes.
R/Jay
Hi Jay. We should save that video on the
psub site for obvious reasons.
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