I found a 3 part series,( its a little over 30 minutes total )on how to repair a squishy deck that I found really interesting and thought I'd share....
Madz the guy that has the SAIL RIGHT channel on youtube has several videos replacing just about his entire cored deck....
....yea, its a sail boat channel, but this guy digs into everything boat with a passion, always trying out new products, rebuilding his galley, installing new deck hatches, complete rewiring with hows and whys, everything boat, etc...
a lot of cross over stuff that goes for most any style of boat.... just a sec i'll get a link.....
he actually did a video chat with the guy from abvove about his cored deck, great channels both of them !