[PSUBS-MAILIST] Group Help Request

Sun Oct 27 16:33:12 EDT 2013

The Dutch are crazy ;-)

My sub was intensive used ;I spend 50 Hours UW the last 3 months. 

The Torque-jet hubless thrusters proved to be perfect, no compensating, no
problem.

The Haswing Protuar at the stern worked also fine and very efficient. The
2.0 HP brushless motor has a big slow turning prop .

The gearbox (15:1 !!) is noisy and it can only be air compensated.

Regards, Emile

The Netherlands..

  _____  

Van: Personal_Submersibles [mailto:personal_submersibles-bounces at psubs.org]
Namens Alan James
Verzonden: zondag 27 oktober 2013 20:53
Aan: Personal Submersibles General Discussion
Onderwerp: Re: [PSUBS-MAILIST] Group Help Request

Thanks Alec.

Forget Minn kottas, this Dutch man is really on to something.

http://www.youtube.com/watch?v=rZJTGqmtzBs

Alan

  _____  

From: Private <alecsmyth at gmail.com>
To: Personal Submersibles General Discussion
<personal_submersibles at psubs.org> 
Sent: Monday, October 28, 2013 8:20 AM
Subject: Re: [PSUBS-MAILIST] Group Help Request

It would be fine as long as the total work being done is held constant. In
other words swept area times pitch for the custom prop equals swept area
times pitch for the stock one. That's assuming equal rpm. 

Once you put on the new prop, verify by measuring the amps drawn. If it
isn't drawing more amps it won't be heating up more than with the standard
prop.

Best,

Alec

On Oct 27, 2013, at 3:07 PM, Alan James <alanlindsayjames at yahoo.com> wrote:

I am wondering whether it is a good idea to change the prop

size on the Minn Kotta. Or whether it would be good to get advice

from Minn kotta first. After reading the issues about sub sea motors &
overheating

I am a bit wary of increasing the load, amps & heat in the motor by
increasing

the prop size.

With regard to Kort nozzles.... I found a design on the internet, then
tracked down a bucket of suitable size & slope, fiber glassed around a
portion of it, then built up the thickness of the leading edge.

Alan

  _____  

From: Private <alecsmyth at gmail.com>
To: Personal Submersibles General Discussion
<personal_submersibles at psubs.org> 
Sent: Monday, October 28, 2013 7:29 AM
Subject: Re: [PSUBS-MAILIST] Group Help Request

Hi Joe,

Thanks for doing this. I have a Minnkota 101 here that I can measure for
you, but I also have some suggestions for your consideration.

Oil or air compensation are both easy and trouble free, so I really don't
see much value-add in the magnetic coupling. Or in a hard case. Ditto
reverse, my trolling motor thrusters with 13 years on them have yet to wear
out the reverse washer, and it's not like I don't use reverse.

Where I do see real room for improvement is with props and nozzles. The
stock props are very short pitched, so if you put several 101s on a small
sub for main propulsion, I suspect you would not get the cruising speed that
their combined horse power would otherwise achieve. In other words, it would
be like putting a big engine in your car but only having first gear.

Emile shared with me that the nice kort on his stern thruster is off a
diving scooter. I researched those briefly and indeed they're in the
ballpark of trolling motor prop diameters, and some appear to be true korts.
Since kort nozzles are hard to make, ID'ing one that's a good match would be
really useful. While looking at scooters, I noticed some have variable pitch
props. By variable I mean adjustable with tools, not adjustable underway.
That could prove a big performance booster for our application.

In summary, I'd encourage a focus on the prop and nozzle, as I've found the
standard seals and reverse to be perfectly satisfactory. My trolling motors
leaked for the first time in 2012, after 12 years of use. I've left the oil
in them for years at a time. When I finally serviced them last year, there
were cheap rebuild kits readily available. 

Do you need the measurements of the inside bits too? 

Best,

Alec

On Oct 27, 2013, at 8:29 AM, Joe Perkel <josephperkel at yahoo.com> wrote:

All Psubber Alert.

A handful of members in conversation off list are coming to the conclusion
that perhaps a best solution to the thruster issues discussed, is to improve
on what has been demonstrated to already be viable. That is Minn Kotas as
demonstrated by Snoopy, Idabel, et al. Parts are readily available and
inexpensive. Case in point here,..
http://www.northlandmarine.com/MinnKotaQuickRef.htm

Hank has graciously offered his efforts in modifying several he already has
on hand, and I am willing to put in many hours of CAD work to come up with
working drawings, with an eye on this armature in particular,..
http://www.northlandmarine.com/MinnKotaArmatureAssy92-100-216.htm

The goal would be to add a mag coupling, Kort nozzle, and true reversibility
to a package that is compact, (4" dia) and field serviceable / replaceable.
The end product result would be open source to the PSUB community.

Immediate problem that needs a solution.

I need a lot of information and detail in order to proceed. Particularly
what I need is dimensioned section drawings of appropriately sized models.
Unfortunately, Minn Kota does not make this information readily available as
demonstrated here,... http://www.minnkotamotors.com/service/ascs.aspx

We need help accessing this information otherwise the effort is hobbled from
the start. If anyone can help in this regard it would help tremendously. 

Joe

Sent from Yahoo! Mail for iPad

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