Re: Edel 665 ...crack in deck / ceiling
The good news is that the Edel 665 is a solid fiberglass deck so this should not be a deck coring issue. The chain plate for the upper and lower shrouds is a two plate affair that is thru bolted between the hull to an inner plate that is anchored to an inner hull molding just aft of your second picture. I would guess that water has migrated through this area and has frozen and split the upper ceiling area where the split is showing up. It will take some minor fiberglass work to repair but I would be surprised if the structure is seriously compromised.
It would still be a good idea to have someone with experience poke around in that split to see if the damage is just superficial to to the interior ceiling material. It would suggest the thru hole bedding in the boat needs to be addressed.