Aerators, also called boils and bubble curtains, are turned on by water authorities in order to counteract stratification (the separation of water into two temperature groups). They have a tendency to attract stock fish, and can hold such large quantities of fish, that the fishing becomes so easy that it is a pointless pursuit. Aerators attract anglers like hot spots do, and the only good function as far as I am concerned, is that it gives me more water clear for drifting.
If the fish are not actually in the boil, then they are thirty yards upwind. The slicks downwind of the boil produce extremely good drift fishing, the fish here can be hard and the methods have already been discussed. What we are considering here, is when the fish are in the boil itself. Incidentally fish for reasons known only to themselves prefer one boil to another. If you are keen to take these fish, then fish the boils quickly to establish which boil they are in.
However as I have already said I am not a fan of boil fishing. It is either incredibly easy or there are no fish in them. You can satisfy yourself as to this fact with the following methods, in all cases use the surface drift to allow your flies to fish around corners.
Boils attract fry; fish plain white or appetiser lures on a floating line.
Even when fry are not around, white lures in the evening can be deadly.
If they don't want white lures, try plain black lures - especially during darkness.
Small nymphs - hares ears and pheasant tail nymphs are absolute killers when fished dead drift.
Dries - especially hares ears and Shipman's - will catch your fish so quickly you will wish you had never started boil fishing.
In the evening, boils have a reputation of becoming harder - there are two reasons for this; the first is that the fish have left, the other is that the fish require dry flies. Dry fly is easy.
If you do decide to fish the boils, then you will probably choose to anchor them. If you anchor close enough you may well snag up on the underwater piping. To free up, release plenty of rope, attach the rope to the stern and row upwind. If that fails try lifting the anchor and then dropping it quickly and that should do the trick.
If you are stuck, you have two options (1) cut the rope as close to the anchor as possible (take care not to fall overboard!) And (2) tie the rope to a buoy - or plastic bottle - and report it to the fishery.
If you use your own anchor, attach the anchor in the manner shown in the drawing.
One last note regarding boils - if night fishing is permitted - try a muddler or failing that, a black lure. I used to use sea trout flies (Peter Ross, Teal and Blue, Black Spider, that sort of thing) for the first part of the night. Then I found the effectiveness of the black lure. It can also work particually well during September fished on a sunk line.