A sloop
schooner
It is a Ketch
A vessel that travels underwater is termed a submarine.
sailer of a light fast vessel
A Xebec
I would call it a Vessel.
vessel
decanter
Veins
Potter .
Many have small valves that keep the blood flowing in the correct direction. You can actually see these if they fail to work. We call them varicose veins.
Xebec