The most common and most likely answer to this crossword clue is the 8 letter word TRIMARAN
I've seen this crossword clue in Financial Times
T
R
I
M
A
R
A
N
More clues leading to the result TRIMARAN
- What is neat on a river – a new boat
- Abridge article about Arabian craft
- Slim American operated boat
- Cut a managed vessel
- Craft dress with a certain knitwear style
- Clip of Irish islands showing boat
- Fit for sailing, managed to secure a vessel
- Boat that’s smart with name of island group
- Decorate a foul docked boat
- Vessel, shipshape, going by group of islands off Ireland
Buddy explains!

The straight part
We know that "vessel" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case vessel = trimaran.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 TRIMARAN mean?
TRIMARAN noun- A type of boat with three parallel hulls.