Bow thruster install. Use windlass wiring?

[guyd]

Is there any reason why I shouldn't use the existing windlass wiring, which is the right size afaik, to power a bow thruster? Then I can use the power down switch for both. Can't envisage a situation where I'm using both windlass and bow thruster....

Caveat, bow thruster is tiny, 1.5kw. boat is small too at 7m. Need to triple check wire size / fuse size

 

[Cardinal]

Mine uses the same wiring and switches, with an extra push switch at the helm when the switches are to operate the windlass. Seems to work.

 

[PaulRainbow]

Is there any reason why I shouldn't use the existing windlass wiring, which is the right size afaik, to power a bow thruster? Then I can use the power down switch for both. Can't envisage a situation where I'm using both windlass and bow thruster....

Caveat, bow thruster is tiny, 1.5kw. boat is small too at 7m. Need to triple check wire size / fuse size

If the cable and fuse are rated for the largest consumer, there is no reason not too.

 

[Boathook]

Is there any reason why I shouldn't use the existing windlass wiring, which is the right size afaik, to power a bow thruster? Then I can use the power down switch for both. Can't envisage a situation where I'm using both windlass and bow thruster....

Caveat, bow thruster is tiny, 1.5kw. boat is small too at 7m. Need to triple check wire size / fuse size

My windlass is connected to the bow thruster wiring going on the theory that I won't use both at the same time. If the windlass wiring is suitable for the current shouldn't be a problem. My windlass also has it's own fuse (75 amp) as the wiring is a lot lighter. The bow thruster one is 250 amp !

 

[CLB]

Windlass on a 7m boat is likely to be 300-500 watt. Unless the wiring was massively over spec'd I can't see it being a viable option.

 

[macd]

As said, it makes sense to double up, providing the wiring is rated for the highest wattage device, which would usually be the thruster. It would also be wise to have a dedicated breaker protecting the lowest wattage element, with a 'master' breaker for the thruster/windlass setup as a whole.

Although, as suggested, in the normal run of affairs the two units would not be run at the same time, it's conceivable that they might be...leaving a stern-to Med-type berth in strong crosswinds or current, for instance. If you don't berth in that way, no problem.

 

[PaulRainbow]

To add a little about cabling and circuit breakers....

The cable obviously needs to be rated for the biggest consumer, if it isn't, it's a non-starter. There needs to be a circuit breaker at the supply end, as close to the batteries as reasonably possible, this also needs to be rated for the biggest consumer. If there is a significant difference in current draw between the two devices it would be prudent to fit a second breaker close to where the new cable connects to the original cable.

It's often the case that we fit fuses/breakers to protect the wiring, with no need to consider the equipment, in the case of a windlass or a bow thruster it's better to protect the equipment (which will safely be well within the rating of the cable, as we oversize the cables to allow for voltage drop). For instance, if the anchor is difficult to break out, or is fouled, you would be better off if the thermal breaker tripped before you overheated the windlass motor.

 

[guyd]

Well, a bit of investigation reveals the installed wire size is 35mm2.

The vetus manual for the 26kgf bow thruster requires a cable size of 25mm for 0-8m boats and 35 over that.

Happy days.

Now the fun of getting the wires to the thruster location.