An artificial fishing fly designed to sink below the surface of the water.Nymph or wet fly fishing is more three-dimensional; dry fly is 2 - D....
To be a successful all-round grayling angler you need a selection of dry flies, nymphs and wet flies.
Boat anglers similar methods and also wet flies, wickhams, soldier palmer, silver invicta on floating/intermediate sinking lines, try orange, black, gold and silver lures.