Trolling motor mount issue

You're not going to like my answer, because it's pretty involved, but I don't like toggle bolts or those rubber trolling motor insert nuts, so.

I don't know how big you access port is, so if it's too small this may not work for you. I had a fairly large access port but it was too far from the mount to reach the bolts.

So I took a thin piece of luan plywood and transferred the bolt hole pattern to the plywood. I bought 1/4-20 stainless steel flange nuts and drilled the holes in the plywood so they were large enough for the hex nut to fit through but the flange protion of the nut would not. Then I glued the nuts to the plywood. To get it into place I drilled one small hole as close to the center of the plywood as I could guesstimate. I also drilled a hole in the exact same location in the boat deck. Then I dropped a pull string through the hole in the boat deck and fished the other end out through the access port and tied it to the hole in the plywood. That allowed me to pull the plywood up under the deck and hold it in place. Then I just used a small screwdriver, inserted through the bolt holes in the deck to manuver the plywood around until I could see that all of the nuts were lined up. Then I just set the TM mount over the holes while holding tension on the pull string and started stabbing the bolts. Once I got one started on opposite corners, the plywood never moved after that.

Now, that plywood is still under the deck. But it's not hurting a thing and it isn't sandwiched between the nut and the deck, so it won't rot out and let the nuts get loose.

Doing ding ding...


Riv nut.

Harbor frieght has a tool to set them for under 20.