Tip voor 2800 bezitters:
Water in rudders of earlier Dufour boats.
Water in rudders of the 2800 (and other models of the same time) is a common problem. If you drill a small hole towards the bottom, it will drain out.
The rudder blade is made in two mouldings and joined at the edges. The stainless steel stock has three plates (tangs) welded out at right angles that are bonded to the mouldings.
People who have had this problem have allowed the water to drain out by drilling small holes, then injected builders polystyrene foam (the material that is used to fill voids around plastic pipes through walls) and the holes refilled with epoxy.
I have not heard of anyone having a rudder fail due to the welds breaking (they are stainless and hopefully the welding was OK), although there have been a few that have split their rudder by grounding it.
A sketch of the stock assembly in the boat, reproduced from one of the very early editions of Dufour News is available here