I did a full inspection of the box, including the load transferring part in engine room. After cutting away the isolation and cleaning the open space of the ceiling I cannot detect any cracks or faults in the construction. The darker spots are leftovers from the glue wich is impossible for me to remove at the moment.
There is a sort of doubling plate on top of the compressionposts and this is not in a perfect straight line but this is the case with all of the ceiling. I imagine the constructors did not care much for esthetics for this part of construction.
However I took a ruler and held it against the bottom side of the doubling plate and this got me worried a bit. I added the photos to the same album and do hope they are clear enough.
The two verticals of the box are basicly the only parts that (as far as I can see now) transfer the compression loads to the posts and are not perfectly centered over the posts below. I measure 3 cm difference on both sides. That means the glassfibre vertical parts of the box are 3 cm to the outside compared to the centreline of the posts. It is difficult to be more precise.
Maybe it is too much to ask but it would be a great help if you could check the situation and state of the doubling plate on your boat. Maybe take a picture so we can compare?
The box and seats are one part I am sure and only bolted to the bulkhead and cockpit floor.. As you can see on the photos there is a flanged metal strip on both sides of the top inside of the box. This is where the cracks are visible on the outside of the box. At the bottom of the box (inside the 2 open storage compartments on both sides of the box) there is a single bolt wich attaches the box to the floor. There is no permanent connection anywhere else, let alone a solid glassfibre connection between bulkhead and box. The nuts of the latter are laminated in in the ceiling of the engine room.
The rigging on my boat was renewed in dec. 2012 and this was done by a specialist sailmaker/rigger in Heyeres. A company well known by Amel in the same place on the med. coast in south of France.
I tightened the rigging only slightly after sailing back to Holland ( 1,5 turns on each turnbuckle.)
I do not know the exact tension/load in numbers. I loosened all the mizzen mast turnbuckles 2 turns now and will see what happens in the next few days. I did the same with the main backstay.
Let me know your thoughts and findings
Best regards, Peter