Ships - they protect against surface damage (8)
I believe the answer is:
coasters
'ships' is the definition.
The answer and definition can be both man-made objects as well as being plural nouns.
Perhaps you can see a link between them that I can't see?
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for coasters that I've seen before include "Small table-mats" , "Merchant ships with a limited range of operation" , "Small mats for Socrates" .)