Bizarre Windlass Problem

[Dockhead]

Originally Posted by s/v Jedi

The key guys, the key. It shears off as a protection mechanism.

Not in my case -- the windlass lifts normally. Only fails to engage to lower.


But the case has been cracked -- turns out this is a very common problem.


In the gearbox.

[wrwakefield]

My LightHouse 1501 windlass has an internal mechanism [documented, but undefined and unknown to me, so let’s call it a ‘clutch’] specifically to prevent using unnecessary force on the ‘down’ [out] cycle.

It is not adjustable like the external clutch. Down only works if there is some load on the outbound chain in the gypsy [e.g., gravity.] If there is no ‘out’ load on the chain, the motor spins but nothing happens- as though the main clutch is not engaged.

This is portrayed in the operator manual as a measure to prevent the windlass from turning the anchor locker inside-out. [My description…]

Is it possible your windlass has the same ‘feature’? [This function is only mentioned fleetingly in my user manual…]

FWIW

Cheers, Bill

[s/v Jedi]

Originally Posted by Dockhead

Not in my case -- the windlass lifts normally. Only fails to engage to lower.


But the case has been cracked -- turns out this is a very common problem.


In the gearbox.

When you confirmed this then of course. But when a key is sheared you can expect anything including still lifting the anchor, because parts of it are mangled and floating around, locking it up now and then etc.

If your case is cracked then it is bad engineering because they should have engineered a weak point that is easily replaced.

[Dockhead]

Originally Posted by s/v Jedi

When you confirmed this then of course. But when a key is sheared you can expect anything including still lifting the anchor, because parts of it are mangled and floating around, locking it up now and then etc.

If your case is cracked then it is bad engineering because they should have engineered a weak point that is easily replaced.

Sorry, an American colloquialism -- "the case is cracked" -- like a murder mystery. The murder case. The culprit has been found.


The literal windlass gearbox case is NOT cracked. The problem is the dog tooth clutch, the same problem many others have had with the same symptoms.

[Tom G]

Yep - the woodruff key is sheared in half most likely. I just went through a similar situation with an old Lofrans. I had to take mine to a shop to pull the gypsy off the shaft, weld and re-cut the keyway. Good luck.

[Dockhead]

Originally Posted by Tom G

Yep - the woodruff key is sheared in half most likely. I just went through a similar situation with an old Lofrans. I had to take mine to a shop to pull the gypsy off the shaft, weld and re-cut the keyway. Good luck.

No, it lifts, just doesn't drop. It's the dog clutch.


I've already sourced a replacement gearbox. I'll overhaul the old one and keep it in spares.

[s/v Jedi]

Originally Posted by Dockhead

No, it lifts, just doesn't drop. It's the dog clutch.

I've already sourced a replacement gearbox. I'll overhaul the old one and keep it in spares.

Please share pictures when you open it. Or do you mean you will have someone else overhaul it? I am very interested to see the fault.

[Bowdrie]

IIRC, what they called a "Dog gear", and the device in the Lighthouse, are forms of "Sprag clutches", one direction always positive, (retrieval,) the other direction having a "Bias" built in to a certain ratio, (load vs engagement,) various springs commonly used to control engagement.
Various types are found in automatic transmissions and in certain types of "Lockers" for automotive differentials.

[Bowdrie]

Addition;
Imagine two shafts end-to-end, each with a flange that has gear teeth on it that have unequal tooth angles, and one of the gear flanges can slide on the shaft a certain distance, and has a spring under it to keep the gear flanges engaged with each other.
In one direction the load will not try to separate the gears, (retrieving the anchor,) but in the other direction the load will force the sliding gear to disengage.
By changing the tooth angles and spring pressure we can change the bias of the force necessary to un-load the gear set.
This is but one simple form of a sprag.

[Dockhead]

Originally Posted by wrwakefield

My LightHouse 1501 windlass has an internal mechanism [documented, but undefined and unknown to me, so let’s call it a ‘clutch’] specifically to prevent using unnecessary force on the ‘down’ [out] cycle.

It is not adjustable like the external clutch. Down only works if there is some load on the outbound chain in the gypsy [e.g., gravity.] If there is no ‘out’ load on the chain, the motor spins but nothing happens- as though the main clutch is not engaged.

This is portrayed in the operator manual as a measure to prevent the windlass from turning the anchor locker inside-out. [My description…]

Is it possible your windlass has the same ‘feature’? [This function is only mentioned fleetingly in my user manual…]

FWIW

Cheers, Bill

That must be the very mechanism which failed on mine. I was ignorant of this aspect of windlass design -- thank you very much for the enlightenment

[Dockhead]

Originally Posted by Bowdrie

Addition;
Imagine two shafts end-to-end, each with a flange that has gear teeth on it that have unequal tooth angles, and one of the gear flanges can slide on the shaft a certain distance, and has a spring under it to keep the gear flanges engaged with each other.
In one direction the load will not try to separate the gears, (retrieving the anchor,) but in the other direction the load will force the sliding gear to disengage.
By changing the tooth angles and spring pressure we can change the bias of the force necessary to un-load the gear set.
This is but one simple form of a sprag.

Thank you!


Learn something new every day

[wrwakefield]

Originally Posted by Bowdrie

IIRC, what they called a "Dog gear", and the device in the Lighthouse, are forms of "Sprag clutches", one direction always positive, (retrieval,) the other direction having a "Bias" built in to a certain ratio, (load vs engagement,) various springs commonly used to control engagement.
Various types are found in automatic transmissions and in certain types of "Lockers" for automotive differentials.

Thanks, Bowdrie.

I’ll make a note in the Lighthouse manual so I don’t forget this nugget.

Cheers, Bill

[Dockhead]

Originally Posted by s/v Jedi

Please share pictures when you open it. Or do you mean you will have someone else overhaul it? I am very interested to see the fault.

I have bought a replacement already overhauled gearbox, but I intend to overhaul the old one myself, so I will definitely post photos when I get around to doing that I'm curious myself what's inside there.

[s/v Jedi]

Originally Posted by Dockhead

I have bought a replacement already overhauled gearbox, but I intend to overhaul the old one myself, so I will definitely post photos when I get around to doing that I'm curious myself what's inside there.

👍 cool, love learning something new

[Fuss]

These winches normally have a bonfiglioli Italian gearbox or smg I think it’s called. Both are the same design, crown wheel and pinion. The normal fault is a complete lack of maintenance resulting in clogged up mechanism that needs mechanical aptitude to clean and grease.
In extreme cases the gearbox runs out of oil as a seal leaks, this is worse with a vertical model.
When this happens then the pinion, which has a ratio of about 60-70:1 burns out. This pinion has very thin gears so it doesn’t take much lack of oil.
So first check the clutch etc, then check the gearbox, the side covers are held on by about 8 bolts.
When this happens, the gearbox often still sounds ok.
A picture would have made all this much easier, instead of all this speculation.