#30182

I would like to retrofit a higher pitch propeller on my 86# thrust trolling motor for a light weight (165# hull) semi-planing boat that is designed to go about 2X hull speed with very low thrust.? I have seen reference to the RC plane pusher props, but I am not convinced that the surface area and strength is robust enough for water applications.? The Navy 3.0 two bladed propeller,?N3-LU05-00, is within 0.1" of the diameter of my trolling motor and probably a little more than twice the pitch (10.2 × 6.73 inch).? The trolling motor RPM is 1,800 with no load, which is 500 less than the Navy 3.0 specification.? Examing the pictures, it looks like a good candidate.??Prior to spending the $50 plus shipping, it would be helpful to know if the propeller will fit.? The key measurements are the maximum hub diameter, shaft diameter, and the shaft length inside the hub from the pin to the front face.? I am also interested in alternative solutions or ideas...

The trolling motor is a brushed DC motor, so I believe there is no change in performance for clockwise vs counterclockwise rotation.? The wires are easily reversed on the output of the speed selector switch and the speed resistors are not sensitive to polarity.? I will also compare the current draw with the stock propeller vs the retrofitted propeller to prevent damage to the trolling motor.

#30183

Let us know how it works out

I have an old 24v trolling motor Thai would like to increase the speed of too

Thx

Show quoted text

On Sunday, January 12, 2020, 05:37, Keith M <penobscot17@...> wrote:

I would like to retrofit a higher pitch propeller on my 86# thrust trolling motor for a light weight (165# hull) semi-planing boat that is designed to go about 2X hull speed with very low thrust.? I have seen reference to the RC plane pusher props, but I am not convinced that the surface area and strength is robust enough for water applications.? The Navy 3.0 two bladed propeller,?N3-LU05-00, is within 0.1" of the diameter of my trolling motor and probably a little more than twice the pitch (10.2 × 6.73 inch).? The trolling motor RPM is 1,800 with no load, which is 500 less than the Navy 3.0 specification.? Examing the pictures, it looks like a good candidate.??Prior to spending the $50 plus shipping, it would be helpful to know if the propeller will fit.? The key measurements are the maximum hub diameter, shaft diameter, and the shaft length inside the hub from the pin to the front face.? I am also interested in alternative solutions or ideas...

The trolling motor is a brushed DC motor, so I believe there is no change in performance for clockwise vs counterclockwise rotation.? The wires are easily reversed on the output of the speed selector switch and the speed resistors are not sensitive to polarity.? I will also compare the current draw with the stock propeller vs the retrofitted propeller to prevent damage to the trolling motor.

#30185

开云体育

I’d recommend looking at what has been done for propeller-driven pedal-power drives.? Model airplane style propellers have been used effectively for these to drive kayaks at around 10kts.? This one by Bob Stuart is about as efficient as they’ve been made:

There’s even a picture here of a pedal-powered kayak (aka “Kawak”) pulling someone on skis…crazy Canadians.

Also check out the old IHPVA link at the bottom of that page.

Here’s a 1981 IHPVA issue where the design of the “Decavitator” hydrofoil design is detailed:

?

Show quoted text

From: [email protected] [mailto:[email protected]] On Behalf Of Keith M
Sent: Sunday, January 12, 2020 5:37 AM
To: [email protected]
Subject: [electricboats] Epropulsion Navy 3.0 Propeller Dimensions

?

I would like to retrofit a higher pitch propeller on my 86# thrust trolling motor for a light weight (165# hull) semi-planing boat that is designed to go about 2X hull speed with very low thrust.? I have seen reference to the RC plane pusher props, but I am not convinced that the surface area and strength is robust enough for water applications.? The Navy 3.0 two bladed propeller,?N3-LU05-00, is within 0.1" of the diameter of my trolling motor and probably a little more than twice the pitch (10.2 × 6.73 inch).? The trolling motor RPM is 1,800 with no load, which is 500 less than the Navy 3.0 specification.? Examing the pictures, it looks like a good candidate.??Prior to spending the $50 plus shipping, it would be helpful to know if the propeller will fit.? The key measurements are the maximum hub diameter, shaft diameter, and the shaft length inside the hub from the pin to the front face.? I am also interested in alternative solutions or ideas...

The trolling motor is a brushed DC motor, so I believe there is no change in performance for clockwise vs counterclockwise rotation.? The wires are easily reversed on the output of the speed selector switch and the speed resistors are not sensitive to polarity.? I will also compare the current draw with the stock propeller vs the retrofitted propeller to prevent damage to the trolling motor.

#30186

The trolling motor is a brushed DC motor, so I believe there is no change in performance for clockwise vs counterclockwise rotation.? The wires are easily reversed on the output of the speed selector switch and the speed resistors are not sensitive to polarity.?

The motor may have the same performance in either direction, but the brushes may wear faster in the counter direction.

The 'timing' of the brushes alters with direction and speed, something complex to do with the back emf causing the fields to 'rotate' slightly.

This effect causes arcing of the commutator. The science and the maths behind is complex field theory and I can't actually get my head around it.

If a motor is intended to run primarily in a particular direction at a particular speed they will rotate the brush assembly slightly to the 'neutral timed' point to reduce arcing and brush/commutator wear.

The Perm 132 brushed permanent magnet motor I use in my boat is 'timed' for a certain direction. I actually operate it in reverse. However, I'm using the motor at about half it's rated voltage and power output. The manufacturer actually notes in the manual that if you run the motor on full voltage, it should be run in the correct direction most of the time to minimise brush wear, but that below a certain voltage there is no appreciable difference.

The large motors used in trams and trains have something called 'interpoles' between the field coils, are connected in series with the armature and these interpoles 'correct' the rotation of the field neutral point and keep commutator always in the 'neutral' point. They do this as the motors have to run equally well in both directions and at the power output of these things any arcing is undesirable. The similar (but smaller!) motors used in the air compressors on the same vehicles do not have interpoles, but the brush assembly is rotated slightly?to the neutral point for the direction of operation.

_._,_._,_

#30192

SW - I will post the results, but probably not until Spring when the water warms up...

Myles - Thanks for the info.? The combination of the human-powered examples along with the information on JavaProp convinced me to buy a RC plane pusher propeller as the first retrofit.? The human-powered examples concerned me a little bit given that the RPM is typically much lower (~360 RPM), and the airfoil shape on the blades could cause cavitation.? I suspect that the trolling motor RPM will still be below the cavitation speed given how much the pitch decays on the outer diameter of the blades.

Matthew - Unfortunately, you are probably correct.? A much lesser problem, I also suspect that the direction of the threads on the motor shaft are optimized for the forward direction.

#30194

Calculations only go so far. Even when you buy a prop from a major prop manufacturer and install it on a a production boat with with a known motor, its still trial and error. If its a plastic prop, you can heat it up and change the pitch by hand.? You will lose performance, since each blade will be slightly different, but if your amp draw and/or speed are better than stock you are ahead of the game.??

I converted a Honda 2.3 to 3 KW? (pics on my instagram). With batteries, it cost around $1100. Cheaper than anything comparable,and totally doable but its not for the faint of heart.?

Matt Foley?

Sunlight Conversions

Perpetual Energy, LLC

201-914-0466

On Friday, January 24, 2020, 08:35:59 PM EST, Keith M <penobscot17@...> wrote:

SW - I will post the results, but probably not until Spring when the water warms up...

Myles - Thanks for the info.? The combination of the human-powered examples along with the information on JavaProp convinced me to buy a RC plane pusher propeller as the first retrofit.? The human-powered examples concerned me a little bit given that the RPM is typically much lower (~360 RPM), and the airfoil shape on the blades could cause cavitation.? I suspect that the trolling motor RPM will still be below the cavitation speed given how much the pitch decays on the outer diameter of the blades.

Matthew - Unfortunately, you are probably correct.? A much lesser problem, I also suspect that the direction of the threads on the motor shaft are optimized for the forward direction.

#30198

Matt - Concur on the calculations, I cannot wait to get in the water.? For the ICE conversion, I would want to use a larger diameter propeller to increase efficiency given the energy density limitations of batteries.? Also, my overall goal is to exceed displacement speeds on a practical hull form with electric propulsion.? Most of the ICE outboards are not well configured for a large diameter propeller.? I would like to identify a brushless small cross-section low RPM motor ideal for a direct drive outboard motor configuration.? The current EV outboards seem to have a rather large price given what is actually on the inside.

#30201

Hi there, my experience with my solar electric boat has been that solar electric powered boats make perfect sense if you want to go more on the slow side such as 6 m/hr (10km'hr). I have found the optimal speed for my boat is 5m/hr (8 km/hr) but my boat design is a displacement hull with a hull speed of about 6.8 m/hr (11 km/hr). As I start to increase the speed from slow to fast the current draw goes up exponentially. If I maintain my cruising speed of 5 m/hr I can travel all day if it is sunny. I have a Torqeedo 2.0 Cruise motor, 221 amp hr battery bank (lead acid golf cart batteries) and 860 watts of flexible solar panels on the canopy. I can travel for 8 hours, stop for the night and while I am stopped the batteries keep charging so in the morning I am at least in the 95% state of charge. If I have a cloudy day I simply reduce my speed and I will draw exponentially less power. I have used this management of battery power for some major trips, one of which I was out for 16 days and solely relied on solar power. I am now building a catamaran 18' long and the plan is to power it by a 20HP motor. I am thinking of an Elco which is just under 9KW. For this configuration I would be into a very large battery bank minimum 16 KW and I could put 1800 watts of solar power to assist. But the solar production for this arrangement would no longer do very much and to recharge the bank would take a couple of days at least. So my thinking is still cruise at a slow speed perhaps 7.5 to 8.5 m/hr (12 to 14 km/hr) but have the option to go fast when required. It all will come down to battery management.

Here is a link to my channel where I have documented my trips.

Regards

Phil

On Friday, January 24, 2020, 09:21:16 a.m. EST, Myles Twete <matwete@...> wrote:

I’d recommend looking at what has been done for propeller-driven pedal-power drives.? Model airplane style propellers have been used effectively for these to drive kayaks at around 10kts.? This one by Bob Stuart is about as efficient as they’ve been made:

There’s even a picture here of a pedal-powered kayak (aka “Kawak”) pulling someone on skis…crazy Canadians.

Also check out the old IHPVA link at the bottom of that page.

Here’s a 1981 IHPVA issue where the design of the “Decavitator” hydrofoil design is detailed:

?

Show quoted text

From: [email protected] [mailto:[email protected]] On Behalf Of Keith M
Sent: Sunday, January 12, 2020 5:37 AM
To: [email protected]
Subject: [electricboats] Epropulsion Navy 3.0 Propeller Dimensions

?

I would like to retrofit a higher pitch propeller on my 86# thrust trolling motor for a light weight (165# hull) semi-planing boat that is designed to go about 2X hull speed with very low thrust.? I have seen reference to the RC plane pusher props, but I am not convinced that the surface area and strength is robust enough for water applications.? The Navy 3.0 two bladed propeller,?N3-LU05-00, is within 0.1" of the diameter of my trolling motor and probably a little more than twice the pitch (10.2 × 6.73 inch).? The trolling motor RPM is 1,800 with no load, which is 500 less than the Navy 3.0 specification.? Examing the pictures, it looks like a good candidate.??Prior to spending the $50 plus shipping, it would be helpful to know if the propeller will fit.? The key measurements are the maximum hub diameter, shaft diameter, and the shaft length inside the hub from the pin to the front face.? I am also interested in alternative solutions or ideas...

The trolling motor is a brushed DC motor, so I believe there is no change in performance for clockwise vs counterclockwise rotation.? The wires are easily reversed on the output of the speed selector switch and the speed resistors are not sensitive to polarity.? I will also compare the current draw with the stock propeller vs the retrofitted propeller to prevent damage to the trolling motor.

Cptn Dave

#30202

If I remember correctly from shop class half a century ago we rebuilt a brushed generator.? ?We were cautioned about reversing used brushes in their slots because "slop" allowed the brushes to cant a small amount.? ?This cant meant the ends of the brushes wearing on the rotor ended up giving the brushes a wedged bottom which if reversed could cause jamming, breakage, or other unwanted problems.? I'm not sure but this might also happen if you reversed the direction of the rotation.? I am not an engineer, but thought it might be something to consider in using brushes in your application.? Being old school, I usually prefer something I can fix as opposed to "discard and replace ".? ?FWIW