Alternatively have a paddle (3)
I believe the answer is:
oar
'paddle' is the definition.
(I've seen this before)
'alternatively have a' is the wordplay.
'alternatively' becomes 'or'.
'have' indicates putting letters inside.
'or' going around 'a' is 'OAR'.
(Other definitions for oar that I've seen before include "Propelling pole" , "Sweep" , "It ends in blade" , "propellor" , "Boat propellant" .)