Board amidships with this? (3)
I believe the answer is:
oar
'this?' is the definition.
The definition suggests a singular noun which matches the answer.
'board amidships with' is the wordplay.
'with' indicates the answer is hidden within the clue.
'OAR' is hidden in the letters of 'board amidships'.
(Other definitions for oar that I've seen before include "Propelling pole" , "Bladed pole" , "Propelling blade" , "Bladed implement" , "Rowing implement" .)