Type of glass vessel (8)
I believe the answer is:
schooner
I believe this clue is a double definition.
'type of glass' is the first definition.
(I've seen this before)
'vessel' is the second definition.
(schooner is a kind of vessel)
(Other definitions for schooner that I've seen before include "Swift sailing vessel - sherry glass" , "wooden vessel" , "Old sailing vessel and large glass" , "Type of glass" , "A measure or glass for sherry" .)