Vikings used this pine club with a hole in it (8)
I believe the answer is:
longboat
'vikings used this' is the definition.
(type of vessel associated with Vikings)
'pine club with a hole in it' is the wordplay.
'pine' becomes 'long' ('long' can be a synonym of 'pine').
'club' becomes 'bat' (as in sporting equipment).
'with' means one lot of letters go next to another.
'a hole' becomes 'o'.
'in it' is an insertion indicator.
'long'+'bat'='longbat'
'longbat' going around 'o' is 'LONGBOAT'.
(Other definitions for longboat that I've seen before include "Viking transport" , "Viking warship" , "one attacking from the north" , "Large vessel launched from a sailing ship" , "Viking ship" .)