Pinnacles reached by hospital rowing crews (7)
I believe the answer is:
heights
'pinnacles' is the definition.
('height' can be a synonym of 'pinnacle')
'hospital rowing crews' is the wordplay.
'hospital' becomes 'h'.
'rowing crews' becomes 'eights' (I've seen this before).
'h'+'eights'='HEIGHTS'
'reached by' is the link.
(Other definitions for heights that I've seen before include "'Altitudes, elevations (7)'" , "Summits" , "Hills, elevated places" , "See 23 ac" , "Distances from top to bottom" .)