Fellow boaters

Looking for some guidance

I have 45ft aft cabin with a hardtop on aft deck, year 2000. A section of aft deck floor has a soft spot approximately 3x3ft square. The spot was soft when I purchased boat 4 years ago and has gotten worse since then. I believe the reason for damage was an ice machine which I have since removed. Fairly certain I dont have water entry anywhere now.

My plan is to drill a series of small holes, 1/4 inch approximately and apply a heater and fan in area for the next few weeks before haul out for winter storage. Hoping the air circulation will dry out some of the moisture. Planning to leave holes exposed until Ontario spring and then fill with resin.

I thought of working from the aft bedroom ceiling up but have heard it's difficult to replace the ceiling and have it look nice once you mess with it. It's a vinyl material that looks quite nice.

Has anyone done this?

I know I will have to patch holes, planning to do this with compound and then apply a non-skid paint.

Appreciate any guidance.

Thank-you