Canoe Trolling Motor Disappointment

[pwk5017]

I started a thread a couple months ago discussing transom mounted trolling motors for canoes. I ended up going with the minn kota 55lb thrust endura model. I needed the motor to get me upriver and figured I would get the biggest they had. Well, I finally received all the pieces of the puzzle on monday and decided to take the canoe out on a local lake to see how the motor would perform. We paddled about 15' off shore and I dropped the motor into the water. At this point I wasnt expecting the motor to lift the front end of the canoe out of the water, but I was thinking the highest setting was going to get me going at a good clip on still water. Well, I turned the tiller to speed 1, I felt a little vibration, but the boat went nowhere. Speed 2 was somewhat similar. Speed 3 was a small improvement, but still no forward progress. Speed 4 finally got the boat to gain a few inches and speed 5 made the old town motor mount slip. I reached back and held the motor mount in place just to see what speed 5 could do, and I would compare it to just myself paddling casually. I have the motor wired to a minn kota power center battery box, which houses an interstate deep cycle 12v marine battery with 218 amp hours. I refuse to believe this motor is functioning properly. The other thread had guys using 28 and 30 lb motors with great results. Is the motor not receiving enough juice, or did I receive a factory dud motor? Any insight on what went wrong/what I should do to start troubleshooting would be appreciated.

Patrick

 

[TimMurphy]

Dear pwk,

How is the motor mounted? Is it stern mounted, or is it slightly off the stern and side mounted on a traditional double ended canoe?

How deep is the motor? A 55 # thrust motor is going to have at least 42" shaft which is far too long for a canoe, 22" - 24" is about all you need. You don't want to have to overcome the drag of 20" of motor shaft, especially when it is offset mounted.

Are you certain the battery is in good condition? If it is new or next to new that's one thing but if it's a few years old it might be past it's prime. They can indicate a full charge on a meter but once you start drawing 30 to 40 amps out of an old battery they lose their zest quickly.

I'm asking these questions after recently taking a 15' Grumman square stern Sport canoe out of a local lake. Olympic level paddlers could never hope to move it as fast as I had it moving into a 15 mph wind with just a 40# thrust motor. And the boat had two people, several fishing rods and tackle boxes plus a cooler with food and drink in it.

Regards,

Tim Murphy 🙂

 

[pwk5017]

Tim, it is your experience(and many others) that had me absolutely dumbstruck. My canoe is 16'-9", and only 32" wide, so its a pretty sleek and slim model. It only had myself(175lbs), my brother(145lbs) and then the battery and motor. It was running as light as I could ever hope it to.

I am using the oldtown standard motor mount in the stern of the boat. It spans the gunwales and then hangs the motor over the side. The motor is the 36" shaft model. Lets say the mount has it a foot out of the water, so the motor submerged 24".

I am not certain of the battery to be honest. I got it through an electrical supplier(dad is an electrician), so I am not certain of its age. The minn kota battery box has a built in charger and I tested it when I got home and it read "full". I might try to grab another battery from amazon or wherever to see if the battery is a dud.

 

[TimMurphy]

I'll add more when I get home from work, but it would be worth getting the battery tested. An autoparts store out to be able to do that for you.

 

[TD55]

My buddy has that same trolling motor on a big huge pontoon boat and it will move the pontoon pretty good across the lake. With it on speed 1 it is perfect for fishing. Something must be up with it.

 

[LongWader]

I think your battery may be the problem and you only need the motor prop to be about a foot under the bottom of your canoe. Most shafts have a sleeve which you can easily adjust. I had a 60 lb thrust which moved an 18' 2,000 lb. great lakes pike boat with two outboards on the back at about four miles per hour with the one of the outboard shafts in the water. Do yourself a favor and get a new deep cycle battery specifically designed for trolling motors and make sure you have a good 12 volt charger. The new gel batteries are expensive, but they last up to 400 cycles and are lighter, more durable, and safer to handle than lead acid batteries. Check you amperage draw and make sure you have plenty of amp hours in the battery you purchase. Also make sure you are not using a SLI battery or a hybrid marine battery. They simply are not up to the task. I would also guess that your 40 lb is a 12 volt and not a 24 volt motor. A 24 volt takes two batteries to run it. I am also assuming that you have a stren mount motor which is what you need. A stern mount with a reverse switch is handy for holding in the current and against the wind. Once you get your set up right with a good motor mount it will turn your boat into a fishing machine and will give you many hours of enjoyment.

 

[pwk5017]

Ok, I think all signs are pointing towards the power source. Either that minn kota power center is limiting the power the motor is drawing from the battery, or the battery sucks.

I have the schumacher deep cycle battery charger(sucker is like $150 brand new, so it should be good).

Heres the thing with the batteries. One, the technical ratings are not standard. Some companies list amp hours, others list amperage. For example, I would buy one of the optima blue tops, but they are only rated at like 55 amps. The only number I have to go off is amp hours from minn kota(should have atleast 105).

Thank God this whole project isnt a bust. You cant even imagine the disappointment I felt walking off the lake. I am 24, but it wasnt a far-stretch comparison from a kid finding out santa isnt real.

 

[TimMurphy]

Dear pwk,

Buy an Interstate Group 24 DEEP CYCLE battery. For a canoe and two fisherman you will be only adding weight if you go larger. Please be sure it says DEEP CYCLE on it and not dual purpose though.

Gander Mountain has them on the self if you have one nearby. Most auto parts stores have them too. I am partial to Interstate Batteries but Exide is another good brand. Even Sears sells Die Hard Deep Cycle batteries.

Regards,

Tim Murphy 🙂

 

[LongWader]

Interstate and Exide deep cycles are very good lead acid batteries that last a long time if you maintain them. I have not had any luck with Sear deep cycles. Make sure that you recharge your battery as soon as possible after you use it. Deep cycles can develop a memory and you don't want your battery to be discharged or partially discharged for long periods of time. If you go on a bass fishing site and ask for help with the right battery for a 40 lb thrust motor I am sure they can point you in the right direction, or check some of the trolling battery web sites.

 

[TimMurphy]

Dear pwk,

When you go for a new battery please take your old battery with you and get it tested. You will be able to turn the old battery in if it is no good and get the core charge removed from the new battery. That will save you $ 10.00 on the new battery.

Where was your battery located and was it mounted on any sort of extended cable? If so you need to be sure that you are using the proper gauge wire to extend the cable. Too thin and you will experience a significant drop in the available current to the motor. 8 gauge wire is sufficient for a 12 volt motor.

Getting back to the motor and mount you really only have to set the motor deep enough so that you can rotate the motor as if you were steering it and make sure that it cannot contact the hull of the canoe with either the casing or the prop.

Any deeper than that and you are wasting energy pushing the extra length of the submerged motor shaft through the water. Those lock rings that are supposed to keep the motor at the proper depth have an annoying ability to work loose and you wind up with the motor much deeper than you when you started.

If you can check the motor out of the water while set up on the canoe check the mount and make sure it is level when installed on the canoe. Some canoes have upswept gunnels at the end of the boat and depending on where the motor is mounted you may have to fiddle around a bit to make sure the shaft is perpendicular to the hull.

Based on the size of yourself and your passenger you canoe wasn't heavily loaded but the distribution of the weight can play a role in how responsive the boat is under power. Again, you want to try to keep the trim of the boat level or very slightly bow up. If you are heavier in the bow that is more resistance to overcome.

It is also difficult to get moving from a dead stop on water with a trolling motor. It is much easier to get moving at the highest possible motor setting and then step back the setting to maintain your desired speed.

Lastly, how new is your motor? If it isn't almost new did you use it recently on another boat? How did it work then? It is possible that the motor itself is tired.

Regards,

Tim Murphy 🙂

 

[pwk5017]

Good point about the angle of the motor and shaft. I thought about that as I drove home from the lake. I am guessing the motor was pointed upwards at a 15-20 degree angle, because the motor mount plate is angled. I will have to adjust next time out.

The motor is brand spanking new. That was actually its first time in water.

I had the battery in the middle of the boat, so that weight is negligible, and myself and the motor in the back(combined weight close to 200lbs). Brother of 150 lbs was in the front. I am not sure how that 50lbs more in the back would effect things.

I am going to pick up another battery tomorrow. I am convinced that has to be the problem. If it isnt, then its the first step in troubleshooting. Do I have to worry about amp hours when I purchase the deep cycle battery, or will any group 24 12v deep cycle battery do? I will be looking forward to the lighter battery, because I have a hulking 27 group ton of lead right now.

Thanks for taking the time to explain some of this stuff. There isnt a lot of info out there on trolling motors as primary forms of propulsion for canoes, so all the wisdom is appreciated.

 

[TimMurphy]

Dear pwk,

Most wet cell Deep cycle batteries spec out the same. You have about 140 - 150 reserve amps of power which is enough to move a canoe around with 500 -600 pounds of payload for a full day of fishing. I don't mean continous operation, I mean motoring to a spot and fishing a drift using the motor to maintain your line and then repeating the process.

The AGM batteries in group 24 are a bit lighter in weight but your wallet will be lightened by double the amount of money if you go that route. Personally I don't think they are necessary for a 12 volt motor on a canoe.

The trim of the canoe and angle of motor in the water are the two biggest things to consider. The way you describe the angle that your motor was mounted it almost sounds like it was lifting the boat upward in the water as much as it was propelling it forward.

Level things out, and with a good battery and you should be all set.

Regards,

Tim Murphy 🙂

 

[Squaretail]

Sell interstates and minnkotas at my work. Tim and Longwader are right on the money.

 

[wbranch]

Something must either be wrong with the motor or your battery is at less than 100% effectiveness. I have a Minn Kota 55# long shaft mounted on the transom of my Hyde drift boat. The Hyde weighs a heck of a lot more than your canoe and I can run up river in moderate flow on the WB Delaware or main stem with no problem.

 

[SurfCowboyXX]

The 40# Minn-Kota I have on my 15-foot canoe can put the boat almost on plane. There is something amiss with your setup, probably power source. That thing should fly with a 55.

 

[pwk5017]

Ok, test #2 was a resounding success. Everyone's guess was correct, it was the power source.

I am pretty pumped to to get this thing on cross creek and parts of the yough to really put it through its paces. Thanks to everyone for the help, especially Tim.