Re: [electricboats] Pocket Trawler Electrification

Again great feedback. 

Agree having rudder in prop wash is not beneficial for regular rudders (multiple references for this conclusion). However for fishtail type rudder used on really slow boats (barge and canal type boats), having prop wash adds a huge facility, reminiscent of bow thrusters.

In general it appears that props in "clean" water work better. Assume suitable depth and distance from hull.

I am now seeing 90 degree turns being possible in a sailing boat length. I have played with my rudder either going straight down and laying out aft. The latter provides huge steerage at low speeds - enough to highly stress the tiller when in reverse.

Best Regards

Lee@vombatus.com.au
0427874796

On 1 Feb 2026, at 7:27 am, maaseidvaag via groups.io <maaseidvaag=yahoo.com@groups.io> wrote:

Hi Matt - I did test steerage this last season with having the boat at cruising speed, going into neutral, and then applying vary degrees of turn on the wheel.  I didn't perceive any dramatic loss of control and could still do a complete 360 degree circle while coasting in neutral, probably in about 3 boat lengths by the (very slow) end of the circle.  With power on I can do the circle inside 2 boat lengths.

 

One hypothesis that will remain just a hypothesis is that straight ahead cruising might slightly benefit from not having the rudder directly in the prop wash.  Probably not an experiment that has been run, but maybe?  

 

Thanks for the feedback,

Lars

Re: [electricboats] Pocket Trawler Electrification

Thanks for the link.  I will configure them as outturning and call it good.

 

Tiny Boat Nation did confirm that I need to send my control and display back to be programmed for reverse rotation.  No charge other than shipping, and they have the LH prop in stock despite it being missing from the website.

 

Thanks - Lars

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Re: [electricboats] Pocket Trawler Electrification

Hi Matt - I did test steerage this last season with having the boat at cruising speed, going into neutral, and then applying vary degrees of turn on the wheel.  I didn't perceive any dramatic loss of control and could still do a complete 360 degree circle while coasting in neutral, probably in about 3 boat lengths by the (very slow) end of the circle.  With power on I can do the circle inside 2 boat lengths.

 

One hypothesis that will remain just a hypothesis is that straight ahead cruising might slightly benefit from not having the rudder directly in the prop wash.  Probably not an experiment that has been run, but maybe?  

 

Thanks for the feedback,

Lars

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Re: [electricboats] Pocket Trawler Electrification

Thanks all for all the feedback and insight.

 

The pods are completely independent of each other with their own controls, motor controller, etc., and can be run with differential thrust.  A failure of any component in one drive won't impact the other, so I should have get-home capabilities.  They will share three batteries that will typically run in parallel with each other but will be able to be isolated if needed.

 

As to low-speed maneuverability, I will have the differential thrust of the two pods and the front mounted Vetus bow thruster which I believe is rated at about 3000 watts.  It's the smallest they make.  Anything longer than a half second blip of the joystick sends the bow sideways in a hurry.

 

Currently, reverse rudder authority is basically zero, with a pronounced prop-walk of the stern to port.  With the new pods I'll should no longer have any prop-walk and can use either differential thrust or the bow thruster to get the boat pointing where I want it.

 

I don't think rudder authority going forward will be an issue either.  I've inserted a very rough image of the anticipated arrangement of the pods versus the existing prop indicated by the red lines.  I will fair the aft end of the full keel to both seal up the shaft log (that will remain embedded in the keel) and smooth the water flow off the trailing edge of the keel.  I'll mount the pods as tight as I can to the centerline, which should put their wash down each side of the existing rudder.  Currently thinking about 4" of clearance between the prop tip and the keel, which is the same as the minimum distance from the top of the prop to the bottom of the hull.

 

As always, all ideas and advice are greatly appreciated.

 

Lars

 

For reference, the current prop in red is 17"x12", and the pod props are 12.5" x 8.3"

 

Actual picture of existing prop and rudder are the second image

 

Re: [electricboats] Pocket Trawler Electrification

Unconventional but I think it might be alright. Sailboats have steerage at basically any speed without prop wash. Albeit with a relatively very large rudder. I built a 20' wide trimaran last summer with rotating pods only about 3' apart. With the pods locked straight you can turn the boat just about on axis, which is much better than expected. 

Matt Foley 

Sunlight Conversions

Perpetual Energy, LLC

201-914-0466

sunlightconversions.com

instagram.com/sunlightconversions/

youtube/sunlightconversions

ABYC Certified Marine 

Electrical Technician 

On Friday, January 30, 2026, 9:15 PM, Myles Twete via groups.io <matwete=comcast.net@groups.io> wrote:

Wow---this seems risky.

 

You're saying that you are going to keep a single rudder arrangement but use 2 fixed pods.

As I see it, you'll have several situations where turning response will be pretty wanting.

I'd be concerned about rudder response in docking/undocking or generally anytime moving slowly and perhaps other scenarios, again, mostly at slow speeds.

 

I've never seen anyone do this before---when going twin prop, either you go with twin rudder or have the props steerable.  And the rudders ideally want to be configured as balanced as feasible (having some area in front of the axis of rotation so the torque stresses are minimized with prop thrust.  Even more ideally, flat rudders replaced with aerodynamic profiles are growing in popularity---Dan Pence did this a couple years ago with the rudder on his electric launch "Ginger", one of the first 2 or 3 electric boat conversions done in recent decades and appearing on www.evalbum.com .  The rudder efficiency was improved noticeably.

 

I helped build a 40ft steamboat cca 2000 that was twin-15hp steam engine powered.  Behind each prop we had a rudder.  Steering was mostly a breeze and on many trips I manned the engines and direction controls.  The ability to drive one prop FWD while reversing the other prop allowed really tight turning in docking.  This would have been seriously hampered if that boat had a single rudder---I actually can't even imagine it.

 

Anyone else with twin-screw experience want to add?

 

-MylesT

 

 

 

From: electricboats@groups.io <electricboats@groups.io> On Behalf Of maaseidvaag via groups.io
Sent: Friday, January 30, 2026 1:30 PM
To: electricboats@groups.io
Subject: Re: [electricboats] Pocket Trawler Electrification

 

I should add, the rudder as pictured in my last post is as the boat was originally constructed.  It was enlarged by a previous owner and is about 50% larger with area added both on the leading edge and trailing edge.  I may be proven wrong, but I don't believe I'll have any problems with sufficient rudder authority after the prop wash is moved off the centerline and to the pods.   And, as mentioned, I have the cheat-code in the form of a bow thruster, which does seem like overkill on a 27' boat.

 

Lars

Re: [electricboats] Pocket Trawler Electrification

Through this thread, I was assuming that there would be separate controls for each of the two pods.

You could almost make the argument that if you had differential thrust available through separate motor controls, you don't necessarily need the rudders.

I have experience with 3 different twin engine boats.  My current boat is a trawler with twin inboard engines.  There are twin rudders - each located behind the prop.  My previous boat had a similar setup.  The one before that was twin I/O's - so no rudders, but steerable engines.  The catch is that the I/O lower unit is located at the very back of the boat.   The other two boats had the props forward of the stern a little bit.  That made a HUGE difference.   While the I/O's were steerable, they were tied together (for steering).   I could use differential thrust - but that worked best when the wheel was centered and the I/O units were straight.  Trying to spin a boat when both of the props are at the back edge of the boat, and close together, is a challenge.   Modern I/O twin engine boats typically have separate steering, and fly-by-wire.  It's EXPENSIVE, but the software allows you to cant the engines in opposite directions to crab the boat sideways.  It's just plain cheating...  LOL!

On my current trawler - it is WONDERFUL to have twin engines!  This makes docking SOOO much easier than with a single engine and rudder!  However, my current marina has a narrow distance between my dock and the dock behind me (the fairway).  To back out of the slip, I use differential thrust only.   To get into the slip, between the competing forces of wind and current - I have found that I am most successful if I maintain a little headway, steer with the rudders, and only use differential thrust once I have crossed the entrance to the slip.   I initially tried pulling into the slip with only differential thrust.  But by the time I stopped the boat, and turned it, either the wind or the current (!! which is MUCH harder to see) would blow me off course.

On a couple of occasions, I have needed to limp back to the dock with only one running engine ("I only need one engine to get home - that's why I have two!").   In those cases I was very lucky to be able to steer into the slip with just the one engine, and no option of differential thrust.   This is the case where I would say you can "almost" make the argument that you don't need a rudder if you have differential thrust.

That having been said - I think I've seen at least one or two boats that had two props and no rudder(s) at all.

Good luck!!!

John

On Friday, January 30, 2026 at 08:15:29 PM CST, Myles Twete via groups.io <matwete=comcast.net@groups.io> wrote:

Wow---this seems risky.

 

You're saying that you are going to keep a single rudder arrangement but use 2 fixed pods.

As I see it, you'll have several situations where turning response will be pretty wanting.

I'd be concerned about rudder response in docking/undocking or generally anytime moving slowly and perhaps other scenarios, again, mostly at slow speeds.

 

I've never seen anyone do this before---when going twin prop, either you go with twin rudder or have the props steerable.  And the rudders ideally want to be configured as balanced as feasible (having some area in front of the axis of rotation so the torque stresses are minimized with prop thrust.  Even more ideally, flat rudders replaced with aerodynamic profiles are growing in popularity---Dan Pence did this a couple years ago with the rudder on his electric launch "Ginger", one of the first 2 or 3 electric boat conversions done in recent decades and appearing on www.evalbum.com .  The rudder efficiency was improved noticeably.

 

I helped build a 40ft steamboat cca 2000 that was twin-15hp steam engine powered.  Behind each prop we had a rudder.  Steering was mostly a breeze and on many trips I manned the engines and direction controls.  The ability to drive one prop FWD while reversing the other prop allowed really tight turning in docking.  This would have been seriously hampered if that boat had a single rudder---I actually can't even imagine it.

 

Anyone else with twin-screw experience want to add?

 

-MylesT

 

 

 

From: electricboats@groups.io <electricboats@groups.io> On Behalf Of maaseidvaag via groups.io
Sent: Friday, January 30, 2026 1:30 PM
To: electricboats@groups.io
Subject: Re: [electricboats] Pocket Trawler Electrification

 

I should add, the rudder as pictured in my last post is as the boat was originally constructed.  It was enlarged by a previous owner and is about 50% larger with area added both on the leading edge and trailing edge.  I may be proven wrong, but I don't believe I'll have any problems with sufficient rudder authority after the prop wash is moved off the centerline and to the pods.   And, as mentioned, I have the cheat-code in the form of a bow thruster, which does seem like overkill on a 27' boat.

 

Lars

Re: [electricboats] Pocket Trawler Electrification

Lars, with the bigger rudder I think you will be fine, especially if you have given them NACA profile.

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Regards,

Paul J. Thompson
IT Manager - Bathroom Direct
(W)09 913 3110 (Mob)021 275 5001 (txt only please)

On Sat, 31 Jan 2026, 15:15 Myles Twete via groups.io, <matwete=comcast.net@groups.io> wrote:

Wow---this seems risky.

 

You're saying that you are going to keep a single rudder arrangement but use 2 fixed pods.

As I see it, you'll have several situations where turning response will be pretty wanting.

I'd be concerned about rudder response in docking/undocking or generally anytime moving slowly and perhaps other scenarios, again, mostly at slow speeds.

 

I've never seen anyone do this before---when going twin prop, either you go with twin rudder or have the props steerable.  And the rudders ideally want to be configured as balanced as feasible (having some area in front of the axis of rotation so the torque stresses are minimized with prop thrust.  Even more ideally, flat rudders replaced with aerodynamic profiles are growing in popularity---Dan Pence did this a couple years ago with the rudder on his electric launch "Ginger", one of the first 2 or 3 electric boat conversions done in recent decades and appearing on www.evalbum.com .  The rudder efficiency was improved noticeably.

 

I helped build a 40ft steamboat cca 2000 that was twin-15hp steam engine powered.  Behind each prop we had a rudder.  Steering was mostly a breeze and on many trips I manned the engines and direction controls.  The ability to drive one prop FWD while reversing the other prop allowed really tight turning in docking.  This would have been seriously hampered if that boat had a single rudder---I actually can't even imagine it.

 

Anyone else with twin-screw experience want to add?

 

-MylesT

 

 

 

From: electricboats@groups.io <electricboats@groups.io> On Behalf Of maaseidvaag via groups.io
Sent: Friday, January 30, 2026 1:30 PM
To: electricboats@groups.io
Subject: Re: [electricboats] Pocket Trawler Electrification

 

I should add, the rudder as pictured in my last post is as the boat was originally constructed.  It was enlarged by a previous owner and is about 50% larger with area added both on the leading edge and trailing edge.  I may be proven wrong, but I don't believe I'll have any problems with sufficient rudder authority after the prop wash is moved off the centerline and to the pods.   And, as mentioned, I have the cheat-code in the form of a bow thruster, which does seem like overkill on a 27' boat.

 

Lars

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