I sense some back tracking now.in case you cant take in what you read 4m thick in places is not the whole hull
In a thread about the loss of a keel, you state:
There are 4 high stress areas in any mono yacht hull:any way they are only 4mm thick in the keel area so prehaps that was why it worked loose and fell off
- Keel attachment.
- Mast base (deck stepped or keel stepped).
- Shroud attachment points.
- Rudder Mount.