Thursday, March 1, 2018

Re: [Electric Boats] trolling motors: pushing or pulling (tractor)?

 

Done that, started a few fires trying. (Burnt out the control boards)
 
-----Trial 1:
17' canoe, 12v 55#motor, APC brand 12" X 6" pitch pusher two blade model airplane Prop.
 
I had to custom craft the spindle and sheer pin interface with the APC Plastic Prop by drilling out the shaft hole  to 1/4" and melting a slot for the motor sheer pin to rest within.
 
Result:
5.5 mph speed according to my iPhone MotionX GPS App, for about 20 minutes. 
(Normal speed with a 4" Pitch stock prop was between 2..8 – 3.4mph, with a Kipawa 5" Pitch  After Market Prop about 4 mph)
 
Notes:
During the trial a fellow boater noticed a trail of smoke coming from my motor's control box.  after liberal application of a Kidd fire extinguisher and disassembling the control head, it seems a negative pole contact must have gotten as hot as a 60 watt soldering iron, melted, then ignited it's plastic housing.
 
-----Trial 2:
17' canoe with an Endura C2 55# Thrust Motor using an APC 12 X 5.5" pitch pusher two blade prop, this time I used a  clamp on Amp Meter. 
 
Results:
Pushed the boat about 5 mph, But the amp draw on from the battery was exceeding the motor's 50 amp rating. (About 65 amps at startup, 55-60 Amps constant)
 
Notes:
So far, I've just decided that 4 mph I get from the Kipawa prop is fast enough for a recreational canoe and can plod along all day at a comfortable clip with no worries about fires.
 
 
Conclusions:
So, my short answer is yes, you can get a small trolling motor to push a small, efficient design boat faster than the stock prop will do with the larger RC Airplane props.
 
But,
1. make sure you are monitoring your motor's amp draw and don't exceed the specifications of the control board for more than just short bursts, otherwise you are going to over heat the relays or the heat sinks on the board.
2. Make sure you bring a real, working fire extinguisher along for the ride.
3. Budget for more than one motor, you stand a risk of burning out the one you are using in short order going off spec with the prop.
 
The APC props are cheap, about $5.00 each, so you can try all sorts of sizes till you dial in the one that fits your boat best, giving you decent speed with a power draw within the specifications of your motor.  I would be interested in the results of your field trials.  I may continue to tinker with these props next boating season.
 
What kind of craft are you trying to push with your 55 pound thrust motor?
 
Thanks,
 
Ken Cooke
Kentucky River USA
 
 
 
 
 
Sent: Thursday, March 01, 2018 9:36 AM
Subject: [Electric Boats] trolling motors: pushing or pulling (tractor)?
 
 

I want to increase the efficiency of my 55lb thrust trolling motor and increase the speed through the water, so I'm studying how people have used model airplane propellers on trolling motors. My understanding is that you can use a larger and therefore more efficient prop, with a larger pitch to achieve a higher boat speed at a lower RPM, if the motor has a PWM controller.

I'd also like to build a NACA foil around the shaft to increase efficiency at high speed. Without a foil, turbulents are visible near top speed.

I'm wondering if anyone has experimented with pulling/tractor props on a trolling motor? My motor (Haswing Osapian) has its shaft quite close to the prop end, so there is not enough room for the trailing edge of a foil between the shaft and prop. If it was pulling, then the shaft could be near the leading edge of the foil.

I don't want to spring for another trolling motor yet.


__._,_.___
Posted by: "Ken Cooke" <ken.cooke@canewoods.com>
Reply via web post • Reply to sender • Reply to group • Start a New Topic • Messages in this topic (3)
Have you tried the highest rated email app?
With 4.5 stars in iTunes, the Yahoo Mail app is the highest rated email app on the market. What are you waiting for? Now you can access all your inboxes (Gmail, Outlook, AOL and more) in one place. Never delete an email again with 1000GB of free cloud storage.

.

__,_._,___
Posted by at

No comments:

Post a Comment

Subscribe to: Post Comments (Atom)