The most common and most likely answer to this crossword clue is the 4 plus 3 letter word LOOK OUT
I've seen this crossword clue in The Daily Telegraph
L
O
O
K
O
U
T
More clues leading to the result LOOK OUT
Buddy explains!
The straight part
We know that "Take care/position on board" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case take care/position on board = look out.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.
Crossword Answer definitions
LOOK OUT noun- A vantage point with a view of the surrounding area.
- A session of watching for an approaching enemy, police, etc.
- A person on watch for approaching enemy, police, danger, etc.
- A subject for observation; a prospect or view.
- One's perspective, outlook; hence, one's responsibility. (used with a possessive pronoun or a noun in a possessive form).