Jack, who could take Paul in? (3)
I believe the answer is:
tar
'jack' is the definition.
(both are informal terms for sailor)
'take paul in?' is the wordplay.
I cannot quite understand how this works, but
'take' could be 'r' (abbreviation for 'recipe', Latin for 'take') and 'r' is present in the answer.
The remaining letters 'ta' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'who could' is the link.
Can you help me to learn more?
(Other definitions for tar that I've seen before include "not put on ship in proverbial case of false economy?" , "Art (anag.)" , "Naval man" , "one may need to pay on deck" , "Sticky cigarette residue" .)