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John John is offline
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First recorded activity by BoatBanter: Jul 2006
Posts: 20
Default Alternator size vs Windlass current


GBM wrote:
I am still trying to decide on a windlass for our boat. Perhaps some the
experienced cruisers can help?

Our alternator output, is nominally 55A, but likely actually quite a bit
less. Max size alternator recommended for Yanmar 2QM15 engine is about 80A)

I would echo the comments made by others here- get a decent sized
windlass and put in heavy-duty wiring. It's expensive, but just part of
the 'hidden cost' of windlass installations.
I've got a Lewmar Concept windass with an 80A breaker, but I'm sure it
never draws anything like that current in practice. Usual anchor is a
35#CQR with 5/16 chain for the first 175 ft, then rope. Alternator is
55A Hitachi, battery banks supply about 300Ah or so. When using the
windlass, we run the engine and parallel the battery banks- probably
overkill.
Wiring (this is important) is 1/0 tinned marine cable with swaged-on
lugs. My marine electrical advisor (Paul Thornton of Oakville, ON)
insisted on this over my objections, and he was right. Boat is 30ft
sloop, batteries aft.

Incidentally- in calm conditions, using chain rode, there's nothing
wrong with moving the boat up to the anchor by jogging the windlass and
letting the weight of the chain pull the boat forward. Once the chain
is close to vertical you can drive ahead with the motor to break out
the anchor and hoist the anchor with the windlass. It's handy having a
cockpit switch for the windlass if you are single-handing.

You will love your electric windlass if you do it right- no more
cranking for me (until it breaks).
Cheers
John