Hydraulic winches which can be randomly activated because of malfunctioning control buttons
When I stepped aboard Sojana yesterday just before racing,
engineer Joe had a hydraulic winch control foot button in bits. There are almost
40 of these onboard controlling the numerous Lewmar winches and furling
systems. They have a dangerous habit of activating winches without warning and
skipper Marc Fitzgerald is slowly working through the foot button components
and changing them in attempt to find a solution that works. The original Lewmar
foot buttons have long gone because they too malfunctioned.
In the early versions, Marc tells me, the air inside the
flat rubber covers to the switches would heat up in the day and distend them.
But at night as the air cooled and contracted the covers would be sucked down
to such an extent that they would activate the internal electrical switch
without warning. The only way to stop the turning winch would be to puncture
the button cover with a knife to release the air or stand on another button
which would automatically stop the faulty one activating. But you had to keep your foot there
until the problem button had been dealt with.
The solution was to fit more heavily domed rubber covers
which couldn’t be inverted as the air within contracted. That worked until the
switches themselves started to malfunction. At first this was thought to be due
to standing water in the cockpit sole (where many of the buttons are mounted)
getting into the mechanisms. So each button was re-mounted onto raised wooden
plinths – quite an operation.
But the switches – new ones are now sourced from China -
still fail because somehow water or damp is getting in.
Sojana is fitted with an emergency hydraulic stop button
which closes down the entire system in the event of an accident. But, as Marc
Fitzgerald pointed out, if you do this you close down the whole yacht and might
put the entire vessel at risk. It’s a difficult and irritating problem to solve
and the modifications are ongoing.
Considering the immense pulling capacity of these winches it
seems extraordinary that there isn’t a fail safe foot button system which can
survive the admittedly harsh marine environment in which they have to operate.