Build up with short two by fours or what ever it takes to get even with the top of the boat, then use "toggle bolts" to secure them to the boat seat. This is similar to what I did.
I need some ideas on how to install a minkota allterrain trolling motor on my jon boat its a foot controlled motor. The platform in my boat is about 3" lower than the top of the boat and directly under the platform is a bench seat so theres really no way to get under there to put nuts on bolts. Its probably not a big deal but I just keep looking at it and my mind is drawing a blank.
Build up with short two by fours or what ever it takes to get even with the top of the boat, then use "toggle bolts" to secure them to the boat seat. This is similar to what I did.
If ya want it to last forever and to do it once, just get a welder to weld you a 1/4" plate to the top of the boat, come back about 18" then drop down to the bench. Your plate should be 18x6.
What about T-nuts? A T-nut is basically an 1 1/2" nut which is circular and is threaded on the inside and fits through a hole drilled in the deck. It has a collar around it which is larger than the hole, and has holes for rivets. Essentially, you drill the hole, push the t-nut through the hole, drill rivet holes through the holes in the collar and into the deck and pop rivet them to the deck. I've never tried them for a trolling motor, but I did use them to attach a swivel seat base to a bench seat. Good luck.
Jim - Have boat - will travel.
The allumi plate on my boat is 2 piece. The 2 pieces are joined with bolts/wing nuts for height adjustment. The lower piece is screwed to the deck and the upper is pop riveted to the rail around the front of the boat. Before I covered the front deck, it was all pop rivets. Ive never had any problems with rivets.