Sit one lecturer in ship that capsized (8)
I believe the answer is:
poseidon
'ship that capsized' is the definition.
'sit one lecturer' is the wordplay.
'sit' becomes 'pose' (as in sitting for a painter).
'one' becomes 'i' (Roman numeral).
'lecturer' becomes 'don' (don can mean an academic).
'pose'+'i'+'don'='POSEIDON'
'in' acts as a link.
(Other definitions for poseidon that I've seen before include "Greek god of the sea and earthquakes" , "underwater missile" , "Greek sea-god" , "being able to create waves?" , "deity" .)