- single-masted ships get a +5 to movement in a strong breeze, while double-masted ships get a +10;
- single-masted ships get a -10 to movement when quarter-reaching, while double-masted ships suffer only a -5.
Broad-reaching is halfway between full-speed and quarter-reaching. I know nothing about sailing, including its ancient forms, and the Wikipedia article on the points of sail is mostly about modern yachts, but it appears that quarter-reaching is the same as beam reach, occurring when the wind is perpendicular to the ship. I should be able to create a diagram similar to the one in the article that covers the basic sail information in visual form.
The crew of an oared vessel must rest after 10 turns of rowing, or 3 turns at +10 to movement, 15 turns at -5 to movement. Maritime barbarians (like Vikings) are better at operating an oared vessel: they get to add an extra turn of rowing to the fastest speed, 3 turns to standard speed, and 5 turns to the slowest.
River travel is at half sailing speed; oared speed is at full speed +/- 5 movement based on whether travel is downstream or upstream.