Interior covering for ship (5)
I believe the answer is:
liner
'interior covering for ship' is the definition.
'liner' can be an answer for 'ship' (as in an ocean liner). I'm unsure of the 'interior covering for' bit.
'interior covering for ship' is the wordplay.
'interior' indicates the central letters.
'for' says to put letters next to each other (I've seen this in other clues).
'ship' becomes 'lin' (I can't explain this - if you can you should give a lot more credence to this answer).
The middle letters of 'covering' are 'er'.
'er' put after 'lin' is 'LINER'.
Can you help me to learn more?
(Other definitions for liner that I've seen before include "Large passenger or cargo ship travelling on regular route" , "Cosmetic item - Titanic, for example" , "boat" , "Large ship or removable layer of material" , "Large passenger-ship" .)