are missing support boards under my floor boards the source of creaks?

[nuru05]

So I was trying to track down the source of a few creaks in my floor boards on my Moody 425. Some of them are rock solid but a few creak annoyingly every time they are walked on. I noticed that the 1/2" support boards are missing on several of these. Is this normal because they are smaller holes or is it worth my time to grab some oak ply and cut them out?

https://imgur.com/aOXp87t

[Cheechako]

I'd be checking how flat the big board fits over the glassed support area. You may need shims in a few places. (Little clay balls can be used by putting them in areas that appear low with a straightedge. Install the floor board then take it off and see how the balls differ.)
But even just inspecting the support fiberglass with a longish straight edge can be a good diagnostic tool. One would think you wouldn't need those 'under boards' at all, but having them in there could solve the problem by reducing flex in areas that aren't sitting down on the glass....?

Bottom line: Usually creaking is a matter of movement, eliminate any flex or movement.

[cal40john]

Are all the ones that creak are removable for bilge access? If so then you can reduce creak by making the access panels less accessible.

[JPA Cate]

You could glue on stiffeners under the bottom of the removable pieces.

An alternative would be to fiber glass in floors to support the covers.

Ann

[zachduckworth]

On the other hand a creaky deck is evocative.

[Pete7]

My Moody has thin strips of of gasket material perhaps half an inch wide were the floor boards touch the GRP liner, which stops the creaking. I will need to replace some of it shortly so perhaps some sort of draft excluding tape is the answer.

Pete