Nida core or plywood for decking?

[horseman]

Hi. I'm a new member, although I've been following the site since I bought my 1970 20' CC 2 years ago. Bought is awesome and in great shape. The deck was soft from just aft of the console to the stern. My question is Nida core or plywood. If plywood what type should I use? If I use nida core do I still need to cover the bottom with woven roven??
Thanks for the help in advance.

[Islandtrader]

I would use coosa board that is scrimed and scored. Nida has no real compression strength so any thing bolted would need to be sleeved.

Welcome to the sight.