Overrides on a winch are a significant danger on any boat, but particularly a multihull.
They usually occur when the sheet is heavily loaded (i.e. when you are powered up) and if on a sheet winch, often prevent the sail from being fully sheeted in. This can result in sail flapping, further sheet tangles, sail damage and steering problems associated with a loss of sail balance.
The risk of overrides can be reduced by the following:
Having the correct lead in angle to the winch
Never pulling in the line between its fairlead and the winch
Having a smaller number of wraps on the winch when the loads are low (and adding wraps when it increases)
Using a larger line diameter.
Prevention of overrides is vitally important, but if one occurs here are a few ways to fix the problem.
First – stop winching immediately as soon as you notice an override. The more you wind in an override, the harder it is to fix.
The next step is to take the line back around the winch drum in an anticlockwise direction and pull as hard as you can.
Usually you need to pull upwards as well.
If you can’t release the override by hand, take the tail of the line to another winch and try to wind the turns out.
Whatever method you use, reducing the load on the line before the winch will help.
If the line is not heavily loaded, crew taking the load on the line by hand may work.
Luffing the boat to reduce sheet tension, or bearing away to make a sail collapse are other alternatives.
If you have enough time, fairleads and winches, you can attach another sheet (or swap the lazy sheet to being the working sheet) to the sail to take the load whilst the override is fixed – but if the sail is flapping trying to tie another line to the sail is dangerous and bound to fail.
If these methods don’t work, tie another piece of rope using a rolling hitch (or use a dedicated loop ‘grabber’) onto the fouled line before the winch, then wind that line on another winch to unload the fouled line.
If the need to release the line is time critical or none of the other techniques work, cut the line as close to the winch as possible (using one of the sharp knives that you have previously positioned nearby).
If the cut line is a headsail sheet, tack immediately to gain control of the sail – otherwise it will flog.
If it is a downwind sail – gybe immediately for the same reason.