Sailors on course must find something to keep them moving (5,5)
I believe the answer is:
epsom salts
'something to keep them moving' is the definition.
I can't judge whether this definition defines the answer.
'sailors on course' is the wordplay.
'sailors' becomes 'salts' (salt can informally mean a sailor).
'on' says to put letters next to each other.
'course' becomes 'epsom' (a race course).
'salts' after 'epsom' is 'EPSOM SALTS'.
'must find' acts as a link.
Can you help me to learn more?
(Other definitions for epsom salts that I've seen before include "Purgative" , "They should clear out!" , "Medicinal preparation" , "Medicine taken for heartburn and constipation" , "a purge" .)