The most common and most likely answer to this crossword clue is the 8 letter word FLOTILLA
I've seen this crossword clue in Independent
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More clues leading to the result FLOTILLA
- A good many coming in to stock a number of small ships
- A lot of craft to satisfy a welcoming crowd
- Vessels? Pour water into area, accommodating collection
- Ships — a good many brought in to replenish Armada, ultimately
- … note about group sick in a small number of boats?
- Case for money secured by First Lord of Admiralty primarily for small 12
- Rolling On The Floor Laughing initially – Hob’s going to head up admiral’s first fleet!
- Pack captures many a naval unit
- Craft loaf to be shifted around part of checkout
- Fleet stacks one in unfortunate fall
Buddy explains!

The straight part
We know that "naval unit" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case naval unit = flotilla.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 FLOTILLA mean?
FLOTILLA noun- A small fleet of warships (usually of the same class), or a fleet of small ships.