Projection to get extremely large ratings here? (10)
I believe the answer is:
forecastle
'ratings here?' is the definition.
(sailors' living quarters - rating can mean sailor)
'projection to get extremely large' is the wordplay.
'projection' becomes 'forecast' (both can mean a prediction).
'to get' means one lot of letters go next to another.
'extremely' says to hollow out the word (remove centre letters) (only the extremes of the word are used).
'large' with its middle taken out is 'le'.
'forecast'+'le'='FORECASTLE'
(Other definitions for forecastle that I've seen before include "located at the front" , "Forward under-deck part of a ship" , "Where the crew may be" , "ship's living quarters" , "Part of Mary Rose" .)