Alternatively get a paddle (3)
I believe the answer is:
oar
'paddle' is the definition.
(I've seen this before)
'alternatively get a' is the wordplay.
'alternatively' becomes 'or'.
'get' indicates putting letters inside.
'or' going around 'a' is 'OAR'.
(Other definitions for oar that I've seen before include "Propelling blade" , "Pole for rowing" , "Rower's implement" , "that may be feathered?" , "Crew member" .)