I think I have a thread here where I explain my frustration with the custom tower manufacturer. They're based in Vonore, TN. They make a lot of towers for some boat manufacturers, but also do custom work for individuals. In addition to the weeks of delay, and never making me the right brackets for the racks, they tore several things up on my boat during installation. Just sloppy installation work. I think they actually did a good job on the tower itself.
So tonight I wanted to make sure the mounting bolts were tight. After purchasing a large allen wrench, I tried to tighten the bolts and while they needed tightening badly, I couldn't get them to tighten. So I pulled the side air vents off to access the nut behind the gunnel of the boat. The support brackets were so small that I consider it negligence. I don't know what they were thinking when they made these ridiculously small backing plates. Needless to say, I'm correcting their mistake. I'm fortunate that I didn't have any issues with the fiberglass last summer.
There's nothing I can do but warn other people to not use this company. Here's the backing plate they used when installing my tower.