Home comfort offered by a marine professor's position (8)
I believe the answer is:
armchair
'home comfort' is the definition.
'a marine professor's position' is the wordplay.
'marine' becomes 'rm'.
'professor's position' becomes 'chair'.
'a'+'rm'+'chair'='ARMCHAIR'
'offered by' is the link.
(Other definitions for armchair that I've seen before include "Sort of detective" , "Place for critic" , "TV viewer's seat" , "Comfortable seat with raised sides" , "Amateur" .)