Once the electric windlass is installed and the cables are installed they require proper protection. When you install protection it is about cable protection, no different to shore power systems. Every primary power supply cable to an electric windlass requires a fuse. These are nominally what are called Slow Blow (time delay) type fuses. They are requirements of the ABYC and the USCG, and some manufacturers integrate this within the control box.
Why are they slow? They are called slow as they are designed not to rupture on short transient duration over-currents that occur when breaking out the anchor, and only when sustained over-currents such as a short circuit or stalled motor occur do they blow. Where solenoid control boxes integrate these and they are located forward close to the anchor windlass, the cable is unprotected, and a circuit breaker or fuse is required for the cable. The protection fuses and circuit breakers must be installed as close as practicable to the power supply source. Make sure you carry a spare fuse as few do! If you have suffered a flat start battery and have put it down to a mysterious leak, check out the anchor windlass connections either at the control box, control circuit or motor terminals. It pays to turn the power off when the boat is unattended.
Circuit breakers are also used for overload protection and also circuit isolation. Circuit breakers are selected with a suitable tripping curve are also used, and also may have the "slow blow" characteristic. They are like fuses and delay opening on low-level overloads, and trip only on sustained over-currents. The circuit breaker or fuses should be installed on the supply as close as practicable and accessible to the battery as possible. Typically these range for 400 watt motor with 40 amp current a 50 amp breaker, 600 watt is 55 amp with 70 amp breaker etc.
A comment about automatic thermal cutouts. I have come across these very occasionally and I would caution against using automatic thermal circuit breakers. They trip automatically in overload conditions and reset. Sounds great doesn’t it. The problem is that you have to wait until they reset, which is usually when you desperately need the windlass.
Always use DC rated circuit breakers, usually available from the anchor windlass manufacturers, and not the AC rated units as some people install. Some boats have automatically resetting circuit breakers for overload protection, however the problem is that you have to wait until it resets, which is usually when you desperately need the windlass, and manual reset breakers offer you some flexibility, although when it trips reset and operate with caution. If the anchor windlass has tripped allow 10-15 minutes for the motor to cool down if it's possible as continued operation may burn the motor out. More electric windlass information and anchor handling information.