TOPIC: 1958 Tomahawk Ski Mate - new seat project

Hi All,

I’m currently in the middle of a restoration project on my fiberglass Tomahawk Ski Mate. I’m at the stage where I’m building a custom back bench seat, and I have two main concerns I’m hoping the experienced builders here can weigh in on:

1. Securely Mounting the Seat to the Floor:

I want to make sure the new bench is rock solid. What is the preferred method for drilling and mounting seats into the subfloor?
How do I ensure I’m not drilling too deep into the stringers or through the hull itself?

2. Evaluating Soft Spots in the Subfloor:

While working on the layout, I’ve noticed a few "soft spots" in the deck. How worried should I be about these?

Can anyone recommend a "non-destructive" way to test the extent of the damage?

Any advice on materials or "lessons learned" from similar vintage fiberglass builds would be greatly appreciated!