As for starboard/port encounters, due to the varying course and high velocity of both boats, it is very difficult to estimate if you on port will be able to pass the bow of a boat on starboard. Do you just wait for the last moment and then tack to starboard?
When possible we can get a pretty good determination if the crossing boat will pass ahead, behind or through us by watch how the other boat is moving relative to the background/horizon. If it looks like it's moving forward against the backdrop, it will pass ahead. Backwards means we will pass ahead. Little or no motion against backdrop means watch out, who's got rights and does he see us?!
Normally, we can see this develop from a long way out with this technique...so we can take small actions earlier to reduce negative effects on our position.
