Windless with a mind of it's own

Skippy J is correct. You have to be on top of the windlass when it appears to working poorly. The clutch could be slipping, the relay box could be chattering, rode could be binding. Most of these need a visual and good ear.

If I recall, the larger Maxwells have flip out handles to tighten the clutch. Never put you back into it to tighten it, just enough to keep it from slipping for normal operation. It is a safety device also.

I have not only put battery toasters on the windlass (& thruster) batteries, but tested at the cable ends. Amazing what I have found in bad cables & connects.

The rode locker is a place that never gets any attention. Never ventilated and a perfect place for GREEN stuff to thrive on electrical connects.

On my Maxwell, there are two female "star" type sockets on top of the windlass. The one on the outer ring is there for manual retrieval in which you use a Maxwell hand crank (same as a sailboat winch). The one on the center area is what you turn to loosen/tighten the clutch. The first thing you need to do is to get someone on the switch where you operate it from and you need to be at the windlass so you can see and listen to what's happening. Obviously, don't put your fingers anywhere near it when it's being operated. I have to troubleshoot mine right now as well. We just went to use it for the first time in months & it wouldn't release or retrieve. My son who was standing near it said he could hear a "clicking" noise when I went to operate it so I'm guessing the solenoid might be hung up. I had to deploy it by loosening the clutch. Then I cranked it up with the hand winch.

I have a (hydraulically powered) maxwell windlass that just developed a mind of its own.......was retrieving anchor using maxwell auto box; hit the button to stop, no response; switched off the fuse on the board, no response; pulled the circuit breaker, no response.... the windlass just keep spinning. Odd. I wonder if this is a solenoid? If so how to check it please... and is it safer to just replace that part? As the winch kept spinning it got hotter and hotter. My guess is that the electrical circuit telling it to stop failed, and the 'hydraulic power' supply wasn't told to quit.... so it keep going. Half an hour later the hydraulic alarms sounded. Bow thruster worked fine, yet Capstans wouldn't fire up again (as I pulled their cut off switches in a case there were on a related system.
Appreciate anyone's thoughts please about where I should start - thanks in advance.

Thanks Capt J for the post. Yes... switch on engines to provide hydraulic power and windlass just runs

Thanks for the posts here guys. was a real help.
Yes - solenoid was the fault. Replaced w new one. When reconditioning old one for a spare, interesting that a small piece of alum metal - like a shard - was found inside. Strange. Not a pump part (no alum there) and pipes are SS or hose. Any ideas? (Um.. could even have been a contamination from techs service desk....)
Also of interest - no shut-off valves to any hydraulic equipment (noting that I have separate Jastram hydraulics system for steering, vs wesmar for everything else). All the techs say "no, never see a shut off valve". But I want to install them - be great to have other gear available if one piece of equipment is u/s.
I have ball valves below the hydraulic storage tank, but they don't shut off the flow (don't know why - could just be fluid draining from pipes as its 25m to bow)?

I was thinking, a shut of valve OR diverter valve. If the pressure is up and not stoppable, I would think deverting it back to a return line rather than cap it and blow a hose or fitting.
I'm sure there is a pressure relief pop somewhere but again, trusting a rarely used part of a pressure system... or just relive the pressure till other valves, breakers, thingies can be turned off when the real fault is realized.

Those are good thoughts thank you Capt J and RCRAPPS. I have a manifold fwd from which windlass and bow thruster are driven so in effect that diverts the pressure.... no?... then a shut off between manifold and each equipment would be effective but the pressure wd be rwlived by flow to the other. Am I thinking about this correctly ? I could put a return valve aft near the engine pto but that would mean losing all my fwd equipment, not just the faulty one. Wdyt?

I think Skippy J and myself need to Come On Down and check this out directly.
Is there cheap rum in NZ?

Are you familiar with a gent George Backhus in your area? Racing sails now days.
Tell him Ralph & Josie in Jax, FL, USA sent you and he still owes me a drink.
You can collect.
He can guide you on this for sure. Heck of a marine engineer.

If you can't find him, Yep, you need to fly J & I on down.
Oh, before your weather turns..

Believe it or not a PTO does not provide any pressure even if rotating at warp speed. The pump that's attached to it does not create pressure either. It does however create flow. It is the resistance to flow that creates pressure.

My understanding of a simple hydrolic system and our thoughts to avoid the OP event.
Pump running, oil flowing thru a loop, out and back. No pressure, no strain.
When a control valve is engaged, it self, diverts this oil flow to the task and then pressure builds up against the pump, building pressure then, against the task (slave) device engaged. Neutral movement of this control valve returns the orbiting fluid cycle to normal loop and the applied flow/pressure is closed off,,,,, holding that applied pressure in place,, until it is released by another movement of that control valve releasing that captured pressure back to the return or oil loop.
Hope I said that correctly.
The OP problem, that control valve would/could not return to a neutral position and relax pressure on the pump and the task device. Run-away engage.

Here is where you can beat your head quickly wondering whats going on, or enable a pressure diverted valve I suggested above.
All task devices are locked in position, the pump pressure returns to a normal loop, no hoses are blown and that safety valve (if installed) is not tested,,usually unreliable or hammering big time that may release pressure on the task slave.
If you will, a manual safety/diverting valve locking all task in position until a calm head can reason what the fault is.

Its gorgeous now. And a EL Nino too so its good for Fiordland too. You totally need to get down here.........there is so much you guys could fix on my boat....lol... seriously.... make that trip.... we'd love it and I'll organise some treats when you get here.... you do so much for the boating fraternity (ahem... and sorority.....).

I will thanks - not found yet and we've looked everywhere obvious. Seems odd that this boat - which has so many built in redundancy systems, as they pretty much thought of everything - would not have this installed.