The stern platform of B51 is electrical, the winch pulls up the platform with a string.
Looks great at first look, but soon....
2 questions come in my mind:
1.what if the winch failed, how we can release it, or pull it up?
2. if the sting breaks, how to fix the platform in up position? there is no extra holes on the platform where I can hold it....
the day before pen Hu regatta, while wahsing the boat, we wish to lower the platform to clear up, inn the mid way, the platform cease to go low, but only can get winch up...
we first winch it up, and try to find out where is the problem. the manual only descript the switch is located on the startboard side, and the control unit is located in the port side, after cabin(the in side of it.)
while opening the hatch, I found a winch motor, a relay and a big black control terminal. (where you can see garmin navigation unit get power from it.)
the small black relay is quite hot....very hot...
the question is that : there are a lot of wires, but nothing get labeled, lacking wiring information, schematic, control diagram, we have no idea how the thing works, there fore there is no way to know which on is which one. I can nto believe this is a german product. according to CE rules, every wire has to be labeled, and can be found in a chart, other wise, there is no one can repair this system.
So, our customer pass a tour without platform to get close to beautiful waters.
26/6 when back to Ma Kun, Mou start to look into the system, we start to try something without and diagram on hand.(which is risky in my knowledge.)
The first Mou found is that there is a rotate part after the winch, he tried to rotate it, and suddenly the platform drop down, this for sure surprised every one.
The rotate part located in a very deep place, you have no way to see it with eyes. after taking a photo with mobile, we release that it's a clutch, rotated ti one way to engage the winch, another way to release it.
but motor is still not working. and now we can't get the platform up.
we unmout the black control block, and dis assemble it, and finally found out a little bit, how this work.
the black one will keep the + and - of motor both on battery negative. if one control enable, it will switch one wire of motor to battery +, if another control active, it would switch another motor wire
to battery +. This is how it control motor rotate in 2 different direction.
But there are still 2 position limit switch, one is located on the deck, near the hanging wire of platform. the other one is a switch inside the cabin, near the winch.
The inside one, seems lost contact with wire, but we can't really understand how it is designed.
after few try, we found out that the out side limit switch controls the the relay, which by some way, feed in control info. so the relay is always on when the platform is at up position. Which means it is always active, once service battery switch is on.( I believe the relay is a chinese one, by that quality, it is normally hot, wondering when it can get on fire.....)
Which trying, Mou found out that the only problem comes from the pulling wire is out of the limit switch on the winch side. Simply re-mount the wire, and it can be active.
the design seems first check the limit switches, when the wire tension is low, then it can't be switched lower. the winch can only be pulled up. when the upper switch is touched by platform(means the platform is on up position), you can only switch down the platform.
Nice design, but the wiring is terrible, we need control chart and wiring diagram in case we need to repair it again.
The power of stern platform need to be separated with an independent switch, so that the limit detection switch won't always active the relay. The relay is very very hot, and bolted on wood, this worrys me from time to time.
