A captain satisfied with royal wind-gauge (10)
I believe the answer is:
anemometer
'gauge' is the definition.
(anemometer is a kind of gauge)
'a captain satisfied with royal' is the wordplay.
'captain' becomes 'nemo' (character from 20,000 Leagues Under the Sea).
'satisfied' becomes 'met' (as in 'met the conditions of his contract').
'with' means one lot of letters go next to another.
'royal' becomes 'er' (abbreviation for Elizabeth Regina).
'a'+'nemo'+'met'+'er'='ANEMOMETER'
'wind' acts as a link.
I am not very happy about this link. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for anemometer that I've seen before include "Wind speed gauge" , "Air Force display unit?" , "Windspeed measurer" , "Wind speed measurer" , "Wind speed instrument" .)