Tiny hole in tank terminal for that old canal boat (9)
I believe the answer is:
vaporetto
'canal boat' is the definition.
(I've seen this before)
'tiny hole in tank terminal for that old' is the wordplay.
'tiny hole' becomes 'pore' (I've seen this in another clue).
'in' is an insertion indicator.
'tank' becomes 'vat' (type of container).
'terminal for' becomes 't' (I can't justify this - if you can you should give a lot more credence to this answer).
'that old' becomes 'o' (abbreviation as in OT - Old Testament).
'pore' inserted into 'vat' is 'vaporet'.
'vaporet'+'t'+'o'='VAPORETTO'
Can you help me to learn more?
(Other definitions for vaporetto that I've seen before include "passenger boat" , "Venetian canal boat" , "Steamboat in Venice" .)