The most common and most likely answer to this crossword clue is the 10 letter word EASTERLIES
I've seen this crossword clue in The Guardian
E
A
S
T
E
R
L
I
E
S
Buddy explains!
The straight part
We know that "Yachtsmen moved by these" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case yachtsmen moved by these = easterlies.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does EASTERLIES mean?
EASTERLIES noun- Any persistent wind from the east (usually applied to broad currents or belts of easterly winds).