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RE: [PSUBS-MAILIST] NR-2 Thruster Arrangement

Or a slim but very practical little tome is Electric Boats, by Douglas Little.
 
Alec



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From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of David Paget
Sent: Friday, July 27, 2007 7:50 AM
To: personal_submersibles@psubs.org
Subject: RE: [PSUBS-MAILIST] NR-2 Thruster Arrangement

James,

 

The book Jay K may be thinking of is “Electric Propulsion for Boats by Charles Mathys”

 

Regards

David Paget

 

-----Original Message-----
From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of Jay K. Jeffries
Sent: Friday, 27 July 2007 9:59 AM
To: personal_submersibles@psubs.org
Subject: RE: [PSUBS-MAILIST] NR-2 Thruster Arrangement

 

James,

For a K-350, this would be overkill, if I remember correctly the main thruster is a 3 HP motor (check the sub’s specs to confirm).  In off-line discussions with Joe, I have been researching 36 or 48 volt AC propulsion.  The controller circuit adds a minor degree of complication to the design but significantly extends the dive time from a given set of batteries.  You don’t waste battery energy with speed control like you would with battery bank switching and resistive control under DC power.  If you search through the PSUB archives sometime after the first of the year, I reference a great book on how to home build a marine AC power system with batteries as the power supply.  I would supply the title myself but all my references are in boxes due to a move.

R/Jay

 

Respectfully,

Jay K. Jeffries

Andros Is., Bahamas

 

A skimmer afloat is but a submarine, so poorly built it will not plunge.

 

From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of Lil Brother LLC
Sent: Thursday, July 26, 2007 7:18 PM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] NR-2 Thruster Arrangement

 

Jay,

 

Take a look at this and tell me if it has enough thrust?

 

 

You seem to be well versed with psub design.

 

James Long
Owner/Designer
Lil Brother LLC (Instrument Division)

----- Original Message -----

Sent: Thursday, July 26, 2007 5:55 PM

Subject: RE: [PSUBS-MAILIST] NR-2 Thruster Arrangement

 

Joe,

James suggestion of proportional control is on the money.  Another consideration for depth control associated with a proportional joystick arrangement is an on-edge dial which is used to dial in the depth you want to maintain.  This makes driving the sub underwater much easier, especially mid-water.  As you know, planes and rudder control are ineffective below 2 kts.  This type of control is regularly utilized on tourist submersibles and ROVs.

R/J2

 

 

Respectfully,

Jay K. Jeffries

Andros Is., Bahamas

 

A skimmer afloat is but a submarine, so poorly built it will not plunge.

 

 

-----Original Message-----
From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of Lil Brother LLC
Sent: Thursday, July 26, 2007 6:21 PM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] NR-2 Thruster Arrangement

 

Joe,

 

I just noticed (the light finally went on) about something you posted

earlier:

 

"Directional control one hand....rate (current flow) the

other. Joystick back all four thrust downward for rise, joystick

forward all thrust upward for descent."

 

I would probably do this different. If done in the appropriate manner, the

controls could be setup proportionally. The further you pushed the

stick...the faster the movement would happen(well the more thrust in that

direction would happen).

 

This would simplify your controls greatly. One hand doing thruster control

(up, down, left, right, and spin about it's vertical axis), and the other

hand handling the rudder(possibly differential primary drive motors)  and

primary drive motors. This does depend on the method of rudder control and

the extent that you are willing to take the control system. This would make

the system totally in both hands other than ballast control, which could be

done as well, but that can be discussed later.

 

This doesn't simplify the surfaced maneuvering problems of the vessel. You

could put an additional button to enable the horizontal thruster for surface

operations(this would also disable the x thrusters). Then the standard

controls could be used.

 

All of this sounds expensive, but it can be done much cheaper than most

people think. Hence the reason I want to help. Plus I need a project to help

with.

 

 

James Long

Owner/Designer

Lil Brother LLC (Instrument Division)