Jim,
I used 00 wire and I believe I figured on 60 feet round trip. I could have used heavier wire to get down to a 3% voltage drop, but I felt comfortable with a 5% +/- drop. Of course much of it depends on the motor. I have a 1000 watt, but if you go with a 1500 watt motor, then you'll need to go heavier. The other option is to have a dedicated battery in the v-berth to power the windlass, but then you need to deal with recharging the battery plus the added weight up front. I ran the wire along the port side from the batteries to the windlass switch at the nav station and up and behind the cabinets along the port side and behind the head cabinets, which of course you'll need to remove to properly run it all.
This is the source I used for the wire.
http://genuinedealz.com/Great service and price....I have no affiliation with GenuineDealz.com, just a great source.
Tom