The most common and most likely answer to this crossword clue is the 7 letter word JETTIES
I've seen this crossword clue in The Daily Telegraph
J
E
T
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More clues leading to the result JETTIES
Buddy explains!
The straight part
We know that "Projecting structures" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case projecting structures = jetties.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 JETTIES mean?
JETTIES noun- A structure of wood or stone extended into the sea to influence the current or tide, or to protect a harbor or beach.
- A wharf or dock extending from the shore.
- A part of a building that jets or projects beyond the rest, and overhangs the wall below.