Bag from overturned kayak finally about to hit the bottom (8)
I believe the answer is:
knapsack
'bag' is the definition.
(knapsack is a kind of bag)
'overturned kayak finally about to hit the bottom' is the wordplay.
'overturned' is a reversal indicator.
'finally' says to take the final letters.
'about' becomes 'ca' (circa).
'to hit the bottom' becomes 'spank' (I've seen this in another clue).
The final letter of 'kayak' is 'k'.
'k'+'ca'+'spank'='kcaspank'
'kcaspank' backwards is 'KNAPSACK'.
'from' is the link.
(Other definitions for knapsack that I've seen before include "Hiker's bag" , "(Hiker's) backpack" , "Bag with straps" , "Hiking bag" , "Traveller's or soldier's bag" .)