Wish I could help. You need someone who really knows about this. I'm thinking jack hammer it all up and start over including a little digout of the soil below and filling with good gravel and compacting properly.
40th Anniversaary X14
'97 Prostar 190 - LT-1 (For Sale)
Prior boats - 2009 X14, 2008 X14, 2005 197, 1988 Tristar 190, 1989 Prostar.