Such varnish doesn't suit the whole ship, I see (6)
I believe the answer is:
mastic
'such varnish doesn't suit' is the definition.
I can't judge whether this defines the answer.
'whole ship i see' is the wordplay.
'whole ship' becomes 'mast' (I can't justify this - if you can you should believe this answer much more).
'see' becomes 'C' (the word for the letter, according to Chambers).
'mast'+'i'+'c'='MASTIC'
'the' is the link.
Can you help me to learn more?
(Other definitions for mastic that I've seen before include "Putty-like cement used as adhesive or filler" , "Substance applied to joints" , "liquor" , "Mac, sit and produce a gum resin" , "Waterproof sealant" .)