Something sailor needs at that point covered by one side of bridge always (7,3)
I believe the answer is:
weather eye
'something sailor needs' is the definition.
(eye to observe coming change in weather)
'at that point covered by one side of bridge always' is the wordplay.
'at that point' becomes 'there' (I've seen this before).
'covered by' indicates putting letters inside.
'one side of bridge' becomes 'we' (I can't justify this - if you can you should believe this answer much more).
'always' becomes 'aye' (archaic term for 'always').
'we'+'aye'='weaye'
'there' inserted into 'weaye' is 'WEATHER-EYE'.
Can you help me to learn more?
(Other definitions for weather eye that I've seen before include "One uses it to keep watch for developments" , "Vigilant attentiveness" , "vigilance" , "Watchful people keep this open" .)