Hull flexing on Oceanis 400

[chamac]

Hi AllI recently took my Oceanis 400 out of the water and have it on a trailer. It is sitting on the keel and is supported outside by pads at the saloon bulkhead and the rear bulkhead at the engine. I noticed the interior floorboards behind the keel are flexed slightly upward. Outside there is a slight "hollow" (for want of a better word) behind the keel. Obviously the weight of the hull and engine is causing the hull to sag slightly behind the keel. If the boat was dried out against a wall on its keel there would not be any support under the keel. Is this slight flexing normal or should the hull be completely rigid here? Is it safe to dry out this model against a wall say for cleaning?Any Ideas would be welcomeRegardsChamac

 

[Rick I]

What's the history of this boat?

What it sounds like is that the glass behind the keel is being pushed up by the back end of the keel. This should not happen. I would check under the floorboard and look at the condition of the glass there, any cracks etc? Any repairs? It may be that the boat has hit something with the keel or grounded hard resulting in the keel being pushed up in the back and weakening the glass.

 

[chamac]

Thanks Rick

RickThanks for your reply.The boat was mostly privately used, thats not to say that private owners dont ground their boats!. I bought the boat last year. It had a good survey. The bend is very slight, just enough to make the internal floor boards behind the keel feel a little loose under foot. There are no cracks visable in the grid under the floor boards or outside. Outside you can see a slight flexing upwards behind the keel. I would estimate its about a half inch off the plane of the hull bottom. The Oceanis is quite flat bottomed behind the keel. Should the boat be totally rigid and flat here? You would expect some flexing when a big percentage of the boats weight rests on the keel. Its my first time to have it on a trailer.