The 6 yellow buoys to the southwest of Langstone Harbour entrance mark a jet ski area in which jet skis are allowed to go as fast as they wish.
Jet skis have no right-of-way over other boats and you can sail through this area, but be aware that jet skis may be travelling fast.
Jet skiing is actually prohibited in The Run (harbour entrance from the outfall northwards) and amongst the moorings, although you wouldn’t know it sometimes. Jet skis are supposed to pass through this area in a straight line to the sea.