What I have - a broom on a navy ship (11)
I believe the answer is:
minesweeper
'ship' is the definition.
(minesweeper is a kind of ship)
'what i have a broom on a navy' is the wordplay.
I cannot quite understand how this works, but
'i' is present in the answer.
'a' could be 'per' (eg 'one a day' means 'one per day') and 'per' is found in the answer.
'navy' could be 'n' (common abbreviation eg in RN Royal Navy) and 'n' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for minesweeper that I've seen before include "In the main, clearer" , "Naval vessel" , "Warship" , "One removing bombs" , "PC game" .)