motor mount problems

Hi – I recently bought a trolling motor and motor mount to make it easier when I take my little kids out canoeing. But the motor mount seems to wobble (it has metal brackets and the canoe has metal gunwales) over time and then fall off. I’m thinking of somehow securing it permanently by drilling into the gunwales and fastening with bolts. Has anyone does this? I just don’t want to lose the motor in the middle of the lake! And a few holes would be minimal damage to an older canoe. Any suggestions? Thanks.


Might try gluing some rubber pads to
the mount brackets and gunnels before you drill, but a couple of 1/4" holes in the gunnel for a more permanent, but still removable (wing/lock nuts?) mount, probably wouldn’t hurt much. The pads worked for my mount. R

Hope You’ve Got It Tethered…
…cause if you don’t, and it jumps ship, it’s bye-bye time - and please, don’t ask me how I know…

you say you have metal gunnels …

– Last Updated: Apr-27-10 12:03 PM EST –

...... are your gunnels round in shape (aluminum I suppose) ??

Reason I ask is , a round gunnel may be at a disadvantage for getting a flat bar and it's clamp mechanism to tighten well and stay that way .

Necessity being the mother of invention as it is , I'm sure such a disadvange could be turned into an advantage in one way or the other though .

This post is a little long , but I've tried to be rerasonably detailed with the wording for clarity in understanding best .

If round gunnels , where would you drill to put the fastner you are considering ??

A flat bar crossing over a round tube will make contact "only" in a very small area on the top middle of the tube . Basically that contact area won't be much wider than a 1/8" line or so at best . That contact area is about the best spot to sink a fastener , but then again ... doesn't the hulls' top edge lay directly beneth the center of the gunnel there ??

Doesn't seem you could devise any sort of thru-bolt (nut below) on a small round gunnel to me , so that would leave only the option of bolting directly into the gunnel (similar to a screw in fashion) . I don't like that idea too much for various reasons .

I suppose you could drill into the gunnel right at the point of contact with the motor brackets flat bar ... but you will probably have to drill down into the hulls' top edge also in order to make a path for the bolt (screw) to travel . I see some problems with trying to drill straight down into the top edge of the hull material . The bit will likely try to bind as it will want to slip to one side or the other , and in so doing may elongate or oversize the precision hole you wanted to achieve in the alum. gunnel .

If you are able to manage carefully drilling into the gunnel and hulls' top edge without the problem mentioned ... I would suggest you plan for using a fine thread bolt and hand tap the drilled hole to match the bolts threads (that requires the proper hand tap bit and drill bit , a matched pair) .

If your gunnels aren't round but flat on top (as in square) , then you may have a better advantage at drilling and fastening directly .

I just believe there must be a better way for you to solve your bracket loosening problem than drilling and fastening directly . A troll motor gives a fair amount of vibration , it also has some torquing going on , and the possibility of the skeg or submerged motor bumping into things occassionally . All that says whatever the motor is secured to (a canoe bracket in this case) , needs to be pretty tightly attached to the canoe (gunnels in this case) .

Direct fastening to a relatively thin guage aluminum gunnel (round being the worst case) , even with machine fine thread bolts that have been hand tapped , will probably have a tendency to loosen because of the torquing effect the motor will create ... this will tend to make the bolts wiggle some eventually , and in turn enlarge the tapped hole some (stretch) , and this process will probably just self degenerate getting worse over time .

Also seems the bracket clamping mechanism is going to have some difficulty getting a good bite on a round gunnel , again because of lack of contact area in clamping part (similar to the top bar) , and also the angle that the clamp part must have to take on a round gunnel .

Let's consider something different for a minute . Suppose you run (install) a good solid flat board across the width of the canoe ... this board would be similar to a thwart brought right up tight to the underside of the gunnel , and it would be placed directly under where you want your motor mount bracket to be .

This special thwart board "could be" attached by fastening through the hull from the outside if nessasary , using good washers on the outside to stengthen the hull skin (Fender washers perhaps , they are the larger diameter type with the exact fastner size hole in the middle)... Even better than the fender washers would be a single flat bar type for the washer (a rectangular flat stock with both fastner holes drilled through it). The fasteners (screws) should be relatively long , 1-1/2" or even 2" (for good depth into the special thwart board) and larger diameter (for better strength) . Just use the proper size drill bit (for pre-drilling) when drilling through the hull into the ends of the special thwart board .

If you like that idea , about the only thing left to do is take up the gap between top of the special thwart board and bottom of the motor bracket flat bar in perhaps two spots , say right in close to the gunnels inside edge . The gap will be the same as the diameter of the gunnel (about an inch , more , less ??) . Just make those two blocks permenantly attached to the top of the special thwart (glue and screw) , and sufficient in size or length (not small but longer than needed for surface contact area between the flat bar and block (that also helps in strengthening as opposed to a smaller surface area of contact) .

From there it should be a relatively easy deal to through drill from top of flat bar , through the blocks and special thwart , with the intention of passing a nice size bolt (brass or stainless) and matching wing nut or (other type nut) to become your new motor bracket to canoe fastening method ... take the original clamps off and put them away somewhere .

It might be over kill , but you could just as well use two through bolts on each side of the bracket for mounting , as opposed to a single bolt each side . When determing where to drill for the through bolts , consider the blocks that have been permenantly attched onto the thwart and the location of any screws you may have used to attach them ... so as to "not" find yourself trying to drill through those screws as well when making the through holes (you really don't need to use screws to attach the blocks to the special thwart , clamp and glue (epoxy ??) would be sufficient ... a couple small screws just help with alignment , just saying ...

Just an idea , but I am always of the mind to design for strength and failproof as possible . (I wouldn't even hesitate to use 7/16" or 1/2" bolt and wing nut for the fastening) ... the larger wing nut will also be easier to deal with for tightening , and easier to deal with when un-tightening .

motor mounts

– Last Updated: May-05-10 2:41 AM EST –

We've tested many motor mounts and found them to not have enough flat surface area to resist twisting. Once a mount starts twisting than it works loose. We're developing a motor mount for the Electric Paddle that withstands this twisting and is easier and quicker to set up. Since you already purchased one though, our experience would dictate screwing flat pads of marine ply to the mount at least 4 inches wide so that they rest along the gunwale. Use flat-head screws so they don't mar your boat. This will stop the racking and give you peace of mind. The extra thickness may require longer clamping screws too. Good luck.