Deliver over split boarding, having no doubt - right? (9)
I believe the answer is:
surrender
'deliver over' is the definition.
(thesaurus)
'split boarding having no doubt right?' is the wordplay.
'split' becomes 'rend' (I've seen this before**).
'boarding' means one lot of letters goes inside another.
'having no doubt' becomes 'sure' (I've seen this before).
'right?' becomes 'r' (common abbreviation).
'rend' put into 'sure' is 'surrende'.
'surrende'+'r'='SURRENDER'
(Other definitions for surrender that I've seen before include "Yield - release" , "Yield to the control of another" , "Capitulate, relinquish" , "Wave the white flag" , "Concede" .)