Situation is this: I have a "ball-valve" type seacock. The handle still turns, but it no longer turns the ball inside the valve. Thus, the ball is stuck in the open position. Don't suppose there's an easy way out on this????
Martijn, Does the spindle turn with the handle or does it stay in the same position. It is possible that the spindle square has rounded. If so, try turning it with either pliers or a pipe grip. BE CAREFUL - VERY CAREFUL. If you can turn it with either pliers or grips, then your only way out is to dry out and replace the valve. If you can't turn it, then you will have to replace the valve.
I would advise that you dry out in any case, before you try anything.
the spindel turns with the handel I'm afraid! Luckily the boat hasn't been launched yet, so sinking is not an option yet. Problem is, as with most boats, that the seacock has been fitted in the most impossible place, making replacing it a nuisance to say the least!