Windlass malfunction

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Senior Member
Aug 27, 2016
Vessel Name
Vessel Make
Tollycraft, 44 CPMY
Windlass situation:

I apologize in advance for a lengthy beginning but there are several pertinent facts/clues to my problem.

I have a 1986 Plath model 9 windlass on my 44’ Tollycraft.

3 years ago I sent it back to Plath for refurb which included bearings, seals, oil change , and brushes.

In my setup, I have an up-down switch at the upper helm and 2 foot switches on the bow deck.
The switches each go to one of 2 solenoids. If I’m interpreting the schematics correctly, the 2 solenoids are normally in ground state. Depending on which switch is activated, the activated solenoid will become positive, leaving the other negative, and the motor will move one direction. While the other switch activates the other solenoid to become positive moving the motor in the opposite direction.

The switches go through a circuit breaker at the lower helm dc panel.

House battery and Stb engine start battery in the engine room each have a large 1/0 or 2/0 positive cable that go to a switch at the lower helm so power supply can be switched between the 2 batteries. A common cable goes from this switch to a 100amp fuse then continues on to the windlass solenoids.

While anchoring out on 2 occasions recently, I had the following problems:

1st occasion:
Anchor deployed fine.
Next day, retrieved the anchor and it stopped while coming up when it got to the bow roller. Can’t remember whether up and down both stopped but “up” definitely stopped. I lashed down the anchor and went home. Back at the dock, fuse checked out ok and the windlass started working normally.

I replaced both solenoids and cleaned up all of the connections going to them.
Also bought a spare 100 amp fuse (foreshadowing).

2nd occasion:

Anchor deployed fine. Next day activated the up switch on the deck and the windlass motor came on briefly then stopped. Both up and down switches from both helms would not work. Checked the fuse at the lower helm and it was blown.
I replaced the fuse and disconnected both upper and lower helm switches from both solenoids as one of the switch wires had some burn marks and a questionable looking butt connection. Additionally, all of these switches are old, so in an effort to eliminate them as a possible cause of the blown fuse, I hooked up a remote start cable button to the “up” solenoid (connected it from the small solenoid post previously used by the switches to the positive cable) and left all switches out of the circuit.

This worked but...

With the remote button on the “up” solenoid, I was able to bring in 15 feet of chain no problem. I then disconnected my bridle from the chain. When I went to activated the remote starter connected to the solenoid again, nothing happened. Not even a brief motor run. Checked the voltage at the solenoid and found none. The 100 amp fuse had blown again.

After a lot more trouble shootings do lacking another fuse, I ended up pulling up 100+ feet of 5/16 chain and 55lb Rocha by hand.

I’m planning to replace the 100 amp fuse with a 100amp circuit breaker.

Other than replacing the switches and their wires, any suggestion of where to go from here?

Why would the “up” solenoid have worked with the remote jumper for 15 feet then fail? (Could it be that with the snubber off, the added weight did something to the amps to blow the fuse?)


  • windlass wiring diagram - tami ii.pdf
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Windlasses take huge abuse, think of your non-electronic car, turn the starter on, hold it. Let it off and do it again. Repeat. Repeat as often as you run your windlass. Every time you hit the switch, the solenoids close and the start current can peak at 1000 amps for a brief time. This arcs the points in the solenoids and you get some arcing at the motor points too. Once the motor is running the current draw drops to its rated level but every time you hit the switch, it repeats.

I go for the simplest solution first:

1. Check all the grounds and all the power connections. Iffy ones need repair.
2. Check the voltage at the solenoids. Should be within 3-10% of the reading at the source. Low voltage will give you a larger than normal current inrush that could pop a fuse. Battery condition?
3. Start substituting the solenoids with a known good one and see if the fault follows (solenoids are the “usual” fail at this point, they handle all the current and they are usually made pretty cheaply - not necessary to buy Plath, good generic truck starter solenoids are good). Old solenoids can be repaired but it depends on how handy you are or just buy new. This is not a place to cheap out. Judging by the failure rate I would just replace them all and examine the removed ones to keep for spares.
4. If none of this works, pull the motor and check the condition of the commutator and brushes.

The control circuits at the helms are low current and may be coincidentally faulty but they will not cause the large fuse to blow.
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