Quite florid keels, gunwales, in vessels (6)
I believe the answer is:
flasks
'vessels' is the definition.
(flask is a kind of vessel)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for flasks that I've seen before include "Narrow-necked bottles, thermos or vacuum" , "Narrow-necked bottles, may be of vacuum type" , "Containers for liquid, thermos say" , "Glass containers" , "Bottles with narrow necks" .)