The most common and most likely answer to this crossword clue is the 5 letter word KAYAK
I've seen this crossword clue in The Times
K
A
Y
A
K
More clues leading to the result KAYAK
- King and leader of armada chat in boat
- Boat that’s kilometres ahead of a large hairy beast
- Inuit canoe seen going up and down
- A rabbit chasing stern of black canoe
- Vessel taking girl a kilometre
- Boat that may roll over, just the same?
- Reversible canoe
- Boat that’s no different after capsizing?
- Boat‘s the same even when capsized
- Canoe up and down
Buddy explains!

The straight part
We know that "boat" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case boat = kayak.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 KAYAK mean?
KAYAK noun- A type of small boat, covered over by a surface deck, powered by the occupant or occupants using a double-bladed paddle in a sitting position, from a hole in the surface deck
- To use a kayak, to travel or race in a kayak.
- To traverse (a body of water) by kayak.