Windlass Blows Fuse - The Hull Truth

jlr · 07-10-2007, 08:32 AM

I have a resettable 70 amp breaker and a 100 amp ANL fuse in the engine room both connected to my windlass. It turns out that the 100 amp fuse has been blowing frequently (and, while I am not aboard). In other words, when I leave the boat and raise/lower the anchor from the bow to make sure it is straight, it all works fine. When I come back to the boat and try to lower the anchor from the pilothouse, the 100 amp ANL fuse has blown. What makes it more curious, is that the 70 amp breaker dedicated to the windlass has not popped. I need to get this corrected. The only thing I can think of is that something else may also be connected to the 100 amp fuse for it to blow while no one is operating the windlass or even aboard the boat. Any ideas would be appreciated. I guess it is also possible that the switch on the panel to raise/lower the anchor may be creating a short so that the 100 amp fuse blows so quickly when I try to lower the anchor, I do not realize it but that same switch seems to work fine after replacing the blown fuse. Aside from the expense, it is getting really annoying to have to go into the engine room to keep replacing that fuse at odd times. Help please. By the way, the windlass is a (Simpson Lawrence). Also, since the 100 amp fuse is between the reversing solenoid and the battery, is it possible that something is shot with that solenoid so that going from using the foot pedals on the bow to the toggle switch in the pilothouse is creating a short? Any help would be greatly appreciated.

yottyboy · 07-10-2007, 08:44 AM

Not clear on what you describe. Where is 100 amp fuse? before breaker? Why? Double circuit protection? Little more info please.

jlr · 07-10-2007, 08:54 AM

The 70 amp resettable breaker is between the windlass and the control box. The 100 amp ANL fuse is between the control box and the batteries. Hope this helps.

Hooked Up · 07-10-2007, 09:35 AM

Check the contacts. A weak contact may cause the windlass motor to draw more current than what it otherwise would need and will cause the breaker to pop.

yottyboy · 07-10-2007, 09:42 AM

Is it just starting to do this or has it been acting this way since installation?

jlr · 07-10-2007, 03:07 PM

Just bought the boat in the Fall. It has been acting this way since I bought it. I guess I could change the two foot pedals, the reversing solenoid and the pilothouse switch but I would hate to have to do that if someone thinks it might be something more scientific than that (ie. the suggestion of dirty contacts). Once again, it is the ANL fuse that blows, not the breaker that is popping.

yottyboy · 07-10-2007, 04:57 PM

I think 100 amps is a little on the light side for this circuit. Assuming that all connections are in order, I'd try a 150 or even a 200 amp fuse. It's supposed to be there to carry the entire electric load as a break between the batteries and the world. Clearly there is some surge effect in the line that's popping the fuse with whatever electric you are running plus the windlass motor...zap.
Another school of thought is to use a dedicated windlass battery mounted forward. If you have the room it may be a good solution.

jlr · 07-11-2007, 08:18 AM

Thanks. Hatteras has marked the spot for the fuse as windlass 100 amp. They usually get it right. My concern with putting in a larger fuse is a fire if there really is something wrong.

yottyboy · 07-11-2007, 09:16 AM

I guess the question is, assuming this circuit only has the windlass on it, why would there be more than 100 amps drawing? Is there any place in the circuit that could cause an open path to ground?

jlr · 07-11-2007, 10:32 AM

Not that I know of unless the solenoid is bad.

wkearney99 · 07-11-2007, 12:46 PM

I'm with the corroded contacts line of thought. Or corroded wire. What gauge wire is coming off the battery through to the windlass? Was this a factory install? Has "work been done" to the wiring for it? There's no way the fuse should be blowing before the breaker unless there's a serious wiring problem between the fuse and the breaker. A heavily corroded wire could potentially cause this. Especially if the wrong type of wire was used. Marine wire is made of tinned strands and better resists corrosion than, say, auto wire. But even marine wire can corrode given time and conditions.

Might it be worth replacing the wire between the battery and the breaker? Perhaps just starting with the breaker? Breakers do have contacts and springs that are also susceptible to corrosion. The breaker might be getting stuck, thus forcing the fuse to take the hit.

You might also consider clamping a DC ammeter around it and measuring exactly how much is being pulled through it.

jlr · 07-12-2007, 12:41 PM

Checked all connections last night. All were pristine. I am starting to believe that part of the problem may be human error. It is possible that my knee may have been hitting the up toggle underway will the anchor was all the way up already. That would certainly pop/blow something but I can't figure out why it would wipe out the 100 amp ANL fuse between the control box and the batteries before it would pop the 70 amp breaker between the control box and the motor.