Re: [electricboats] Epropulsion Navy 3.0 Propeller Dimensions

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

Phil Boyer

Phil Boyer

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

https://microship.com/bob-stuart/

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

http://lampi.us/mike/boating.html

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:

http://www.ihpva.org/HParchive/PDF/31-v9n3-1991.pdf

 

 

 

From: electricboats@groups.io [mailto:electricboats@groups.io] On Behalf Of Keith M
Sent: Sunday, January 12, 2020 5:37 AM
To: electricboats@groups.io
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.