Across
4
Sharp blow – large quantity (5)
10
Of the Boat Race contenders? (8)
12
The Starry Night, for example (3,8)
17
Strong current beneath the surface (8)
19
Foul odour – syncopated music (4)
20
Mineral used in plaster of Paris (6)
21
Plane without an engine (6)
22
Expression of non-committal response (2-3)
23
Troublesome (as reef or sheepshank?) (6)