Forester's skill with timber ships (9)
I believe the answer is:
woodcraft
'forester's skill' is the definition.
'woodcraft' can be an answer for 'skill' (woodcraft is a kind of skill). I'm not certain of the 'forester's' bit.
'with timber ships' is the wordplay.
'with' means one lot of letters go next to another.
'timber' becomes 'wood' (I've seen this in another clue).
'ships' becomes 'craft' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'wood' put next to 'craft' is 'WOODCRAFT'.
Can you help me to learn more?
(Other definitions for woodcraft that I've seen before include "Carpenter's art?" , "Skill in camping and related pursuits -- card of two (anag)" .)