I'm wanting to get some drift master or monster rod holders but don't know how to mount them to the boat. Can I put them on the gunwale? If I do there's no way to put a nut on the bolt. So it would just be screwed down. How should I mount them? Thanks.
I am assuming you are installing these rod holders for actual trolling for fish and not just to hold the rods as you travel the water. If that is so, then some people install rod holders to a piece of angle aluminum or even a wood plank and place that across the hull and attach to each side. You could use a screw type clamp if you don't want to drill into the hull, or anything that can hold them secure. Then as you troll you can watch and grab any rod that hooks up with a fish. If you don't want to set that system up, anything that you could attach teh rods to will work with a screw type clamp.
Here are a few options of a screw type clamping setup. JMHO
To make it easy to fish while you're steering the boat, place the rod holder at a 90-degree angle from the centerline, making sure the area under the gunwale is free of wires and other potential obstructions.