submersible
semi-submersible
noun[ C ]
mainly UK(also mainly USsemisubmersible)uk /ˌsem.i.səbˈmɜː.sə.bəl/ us /sem.i.səbˈmɝː.sə.bəl/
a vehicle that can travel or operate by floating just below the surface or water:
The company offers tours in which passengers can observe the coral reef in either a semi-submersible or a glass-bottomed boat.
Among the company's vessels are two semisubmersibles operated in the Caspian Sea.

SMART Vocabulary: related words and phrases

Passenger, cargo & military ships
banana boat
car ferry
clipper
coaster
container ship
Corvette
cutter
flagship
jetfoil
liner
Q-boat
schooner
ship
steamboat
storeship
submersible
tall ship
transport ship
trawler
warship

Related word