It may scratch part of the boat alongside (5)
I believe the answer is:
talon
'it may scratch part' is the definition.
The definition suggests a singular noun which matches the answer.
'of the boat alongside' is the wordplay.
'of' indicates a hidden word.
'TALON' is hidden in the letters of 'the boat alongside'.
Can you help me to learn more?
(Other definitions for talon that I've seen before include "One hooked on bird" , "one that grips" , "Claw; undealt cards" , "Eg, an eagle's claw" , "Part of hobby" .)