The most common and most likely answer to this crossword clue is the 8 letter word OUTBOARD
I've seen this crossword clue in The Daily Telegraph
O
U
T
B
O
A
R
D
More clues leading to the result OUTBOARD
- Doubt oar will be seen moving, having this kind of motor?
- Engine starts to overheat dangerously when modified with a turbo
- Exhausted, get on motor of a sort
- Boat launched with bosses in attendance?
- Motor in the open panel
- Old tub moved by means of propulsion attached at the back?
- Motor’s way below old scuttled U-boat
- Engine, perhaps, forbidden support for pieces
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 = outboard.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 OUTBOARD mean?
OUTBOARD noun- An outboard motor.
- A vessel fitted with an outboard motor.
- A studio having outboard gear (compressor, equalizer, etc.).
- Situated outside the hull of a vessel.
- Positioned away from the centre line of a ship or aircraft.
- Being or relating to an external effects unit such as compressor or equalizer.