Do you have conduits internally?since your not using heavy wire you'll be able to add some extras in case you have problems down the seaway.
If no conduit, be sure to add some zip tie "springs" to keep the wires from banging internally.
Boat wire 2or3 conductors is good, don't know how tall your
mast or how long your maximum run is but #12 wire should give you more than enough
current carrying ability up to 100ft or so.
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