Bow thurster

Apr 22, 2019
9
Hunter 44ds Rothesay
Have just installed lewmar 185tt 3 kw( or 4 hp) bow thurster into 2006 hunter 44ds. Tapped into windlass electrical cable but problem is thurster will trip windlass breaker if held on for more than 5 sec at a time. Looks like windlass cable is 1/0 ?? But I think thurster needs 2/0 or even 3/0. Anyone have thoughts on this. Thanks.
 
Jan 4, 2006
6,444
Hunter 310 West Vancouver, B.C.
Hi Mike and welcome to the site.

This site contains all sorts of technical data but you'll need to do your homework to come to the right answer. No one else has your boat so they don't know either without doing the calculations

Your bow thruster has a rated current draw. Your windlass has a circuit breaker. And therin lies the answer.

However, for two pieces of equipment with heavy draws like this, you should have two sets of cables with two separate breakers.
 
Jul 21, 2019
1
Hunter 44ds Rothesay
The breaker for windlass is 70 amps, bow thurster is rated for 330 amps. Guess that is the issue...looked in owners manual and windlass is on 6 guage with a total cable run of 60 feet. Will need some professional help but charts tell me this bow thurster at that length of wire run could need 000 cable.
Wondering if I should replace the windlass cable or just run new 000 cable for bow thurster.
Certainly appreciate your help. Thanks
 
Jan 19, 2010
12,362
Hobie 16 & Rhodes 22 Skeeter Charleston
The breaker for windlass is 70 amps, bow thurster is rated for 330 amps. Guess that is the issue...looked in owners manual and windlass is on 6 guage with a total cable run of 60 feet. Will need some professional help but charts tell me this bow thurster at that length of wire run could need 000 cable.
Wondering if I should replace the windlass cable or just run new 000 cable for bow thurster.
Certainly appreciate your help. Thanks
I would ask "why replace perfectly fine wire if you are going to run new wire anyway?" You will still have to put in a new breaker to protect the wire so...

I'd just run the new wire and put in the correct breaker and leave the windlass circuit alone.
 
Jan 4, 2006
6,444
Hunter 310 West Vancouver, B.C.
Hi again Mike,

I'm just naturally curious, so just tell me to pi$$ off if I'm going too deep here.

1. The breaker on your windlass seems extremely small which, if it came as part of a windlass package, means the windlass is undersized for your size of boat.

2. I'm too lazy to calculate the voltage drop, but #6 wire may be a little undersized for your windlass circuit of 60" (or is it 120" round trip ?). Sorry, but I forgot to include the attached chart in my previous post. I"ll let you calculate the voltage drop. The breaker is properly sized if the #6 wire is a single wire in open air but I'm betting there's not a lot of voltage left by the time it gets to the windlass.

3. Gotta do the calculations to get the right wire size and remember, you need two separate circuits with two separate breakers.

4. Definitely DO give @Dave Groshong a call as he is the expert here (and I'll bet he's free as well).

5. Just curious but why do you have a new identity in your second post ? Enquiring minds need to know :redface:.
 

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SG

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Feb 11, 2017
1,670
J/Boat J/160 Annapolis
How old is you current windlass cable? Was is a marine grade cable or just a general conductor?

the voltage loss is only one issue, the other is actual capacity to carry watts.

Insulation on the conductors are water barriers but are somewhat gas permeable.If the wire in the cable isn’t tinned, it can corrode within the cable. The voltage will look fine, but the effect is to diminish the effective conductor.

i would either add a dedicated breaker and wire going forward for the bow thruster; or maybe consider a separate battery forward so that you didn’t deal with the voltage loss. The separate battery has some advantages, but comes with a host of other issues (e.g.,charging, switching, fuses, battery type consistency, etc.). Some have championed the advantages of no running “finger sized” cables forward and aft. I have not done it on our boat, but I don’t have a bow thruster.
 
Dec 25, 2000
5,702
Hunter Passage 42 Shelter Bay, WA
Our 1991 boat came with a Maxwell windlass with an 80 amp breaker. The wire is either 1.0 or 2.0 marine grade and the system seems to work fine over the many years of its use. Only one time soon after taking possession did the breaker trip when the chain became jammed and I did not release the foot switch quickly enough. There have been times when the windlass motor struggles to unseat the anchor that is buried deep in the mud, but I usually work it in short cycles until the anchor frees. No want or need for a bow thurster :).
 
Jan 4, 2006
6,444
Hunter 310 West Vancouver, B.C.
Hi Terry,

Please forgive my enquiring mind (and the endless winter here), but when I compare my Lewmar windlass to yours and compare our boat sizes, the don't seem to add up. Obviously your ground tackle is much heavier than mine and yet my power draw seems to be more than yours:

Windlass Amperage.JPG


I know that my windlass is right on the border for my anchor and rode weight (their calculation at 60 lb. and my weight at 65 lb.). Any idea what your ground tackle weighs ?
 

SG

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Feb 11, 2017
1,670
J/Boat J/160 Annapolis
The tackle weight is sort-of a misnomer, in my opinion. You have the theoretical notion of a windless, zero current, zero sea state condition...then you have the question of what's the depth that you're pulling what length of what weight rode. In your Vancouver with your hugely variable tides, you might be anchoring in 10' of water and raising the anchor in 25'. Is the effective length of chain you're pulling up at a 45 degree angle to the bottom? Are you pulling the boat forward, or just pulling up after motoring up.

Windlass motors are often really like engine starting motors. The motor heats-up, develop internal resistance if you run them a while --- especially when under some real load.
 
Dec 25, 2000
5,702
Hunter Passage 42 Shelter Bay, WA
Hi Ralph, no clue regarding the power draw of our windlass. Never have done a check to see just what the actual draw was since I solo most of the time. What we have on our boat is a 40 pound Danforth with a 20 pound lead kellet with 50 feet of chain, which I estimate weights about 60 pounds, maybe a bit more. The windlass seems to handle that load quite well, that is until certain conditions inject more, such as a strong wind, unseating the anchor from a deep mud set, some debris stuck to the anchor like a piece of logging cable, a lost anchor, water pipe, etc. I can usually tell how hard the windlass is working and will adjust its activation so as to avoid overloading.

In normal conditions I will pull rode in by hand until I feel I've reached the kellet, then I'll use the windlass. I recently changed the process by using a messenger line on the kellet to bring it up first before activating the windlass just to reduce the amount of effort. You raise a good point and the next time I have crew on board I'll do a check just to see its draw. I suppose the windlass manual should have that information as well.

A foot note: 100' of 5/16" BBB weighs 113 pounds, so 50' is pretty close to 60 pounds. I was going by how much the plastic bucket full of the chain felt like back when I carried it to the boat.
 
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Jan 4, 2006
6,444
Hunter 310 West Vancouver, B.C.
The tackle weight is sort-of a misnomer, in my opinion.
Misnomer is an understatement. The entire technical write up is nothing more than some sales team's pile of :poop:#^$%@*&^:poop: fricking bull crap. :poop:

Windlass Amperage.JPG


Looking at the V1 I purchased .................. Oh Wow ! ! ! ! 1,000 lbs. of typical maximum pull. That's TYPICAL everyday maximim pull, not a special maximim pulling force (whatever the hell that means). The rotor would have locked long before that 1,000 lbs. pull was reached. The 90A breaker would have tripped long before that 1,000 lbs. pull was reached. I'm too lazy to do a stress analysis but I know my anchor roller mount would have deformed before that 1,000 pull was reached.

Now the chart tells me the working load (pretty clear there) is really only 250 lbs. The boat and windlass equipment should be able to handle that, right ? Don't even think about using that to lift 250 lbs. on a working basis. Dummpkopf :evil: ! ! ! !

The windlass installation manual then tells us:

VI Pulling.JPG


Which simply means to divide the working load (250 lbs.) by "4" to get the real, true, honest to god, no fooling, working load for the V1 windlass (62.5 lbs.) No more, no less.

I've hauled in our 400 ft. of tackle (65 lbs.) in deep water and the motor just heats to palm temperature. What a load of crap. Just state the damned allowable, prolonged, working load (without the factor of safety) from the get go and be done with it.
ALL 62.5 LBS. OF IT.
 
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Jan 4, 2006
6,444
Hunter 310 West Vancouver, B.C.
Hi Ralph, no clue regarding the power draw of our windlass.
Terry, without the make of your Maxwell windlass, I really can't say what weight of tackle it's sized for and where your boat size fits into the overall grand scheme of things

What I can tell you is that spec'ing cranes for raising 10 story natural gas contactors (in a previous life) was a piece of cake compared to sizing a Lewmar windlass.
 
Dec 25, 2000
5,702
Hunter Passage 42 Shelter Bay, WA
without the make of your Maxwell windlass, I really can't say what weight of tackle it's sized for and where your boat size fits into the overall grand scheme of things
Next trip to the boat in a week or so (routine check) the Maxwell manual will have the model and related information for a more informed discussion about our system. Our boat weighs 35,000 pounds (local travel lift operator) cruise ready. Under normal calm conditions the windlass preforms effortlessly bringing up approximately 120 pounds of ground tackle (anchor 40, kellet 20, chain 60). I've been working with this windlass and system since 2002 when we took possession and have anchored hundreds of times. What can I say but that it is a marvel in performance.