Will be primarily using Don't Give Up the Ship! (Ref) by Arneson, Gygax, & Carr (TSR), GURPSified here and there.

House Rules & Adjustments

Change in speed requires making/shortening of sail. (In the rules as written, this is implicit, but not explicit.)
Use 3×Range for guns ("realistic" range adjustment, per DGUtS! suggested rule)

GURPSification