Last in Henley, German eight’s boat (5)
I believe the answer is:
yacht
'boat' is the definition.
(yachting is a kind of boating)
'last in henley german eight's' is the wordplay.
'last in' suggests the final letters.
'german eight' becomes 'acht' (German translation of 'eight').
The final letter of 'henley' is 'y'.
'y'+'acht'='YACHT'
(Other definitions for yacht that I've seen before include "Light sailing-vessel for sport" , "Light sailing vessel" , "Sailing-boat" , "Kind of boat" , "Fast sailing vessel" .)