"Gary" wrote

Finally, how did you determine that risk of collision existed with
this yacht? What piece of information was key to causing you to
maneouvre?

I had a very good sight of his stem head remaining exactly in line
with the masts for a long period of time in a steady wind during which
he remained in the same place behind my bow pulpit.

After I ran off about 100 yards, making a clear enough course change
demonstrate an intention for us to pass "one whistle", he passed
about 50 yards to windward. That means he might have cleared if no
action had been taken but it would have been equally close and it
would have put him close to leeward which is a bad place for a
closehauled sailboat because it can not change course to increase the
passing distance if a misjudgment has been made by either vessel.

I agree that Wayne is wrong about the "miss is as good as a mile".
Except in confined waters where it may be necessary, there should be
some margin for safety and wake. It's all well and good to say you
shouldn't be out there if you can't take it but the reality is that
sailboats sometimes have people below cooking or who can just fall.
I'm not saying they shouldn't be exposed to any wake but the still
breaking wake within a couple wave lengths of a large vessel passing
much closer than it should is something entirely different. The boat
and I can handle it but who knows who is down below.

Assessing how much "buffer" is appropriate to each crossing situation
is just a basic part of seamanship. Sailboats sometimes need to head
up or bear off quite suddenly to avoid excessive heel angle and
possible loss of control. A clean pass means leaving room for those
possibilities. I do the same for lobsterman who may need to suddenly
circle around as they pick up a buoy. If you "just miss" a trawler
yacht that is yawing and on the edge of a broach in steep quartering
seas, it's not a clean pass because you got inside his safety zone.

--

Roger Long