DELAMINATION of the KEEL sump tank. [E26]

When repairing our keel we discover something is not quite right. Well, discover is perhaps a bit of a lie. We did spot that unusually dark spot at the bottom of the keel, however up until now we kind of dismissed it..but it was in the back of our mind. I think we were just worried that digging deeper will open a can of worms. It feels like this "sump tank" and all that business with the oil has been haunting us from day 1. We can't ignore it any longer... Something has to be done about it, and awe have to do it right.