Some thought it a nice old vessel! (7)
I believe the answer is:
titanic
'vessel' is the definition.
(I've seen this before)
'some thought it a nice old' is the wordplay.
'some' indicates the answer is hidden within the clue (some of the parts of the word are used).
'TITANIC' is hidden in the letters of 'thought it a nice old'.
(Other definitions for titanic that I've seen before include "made of metal" , "Colossal, liner" , "Sunken vessel" , "Ill-fated liner" , "like Oceanus" .)