Downrigger Mounting Bases - Cannon h1 9 Gimbal . Cannon mounting bases designed to hold your downrigger in a variety of configurations and sizes. A B C D E F G H1 H2 I Tab Lock Base Big Body Standard Mid Size Standard Low Profile Swivel Deck Plate RailSide Mount Clamp Mount 9 Gimbal Mount 12 Gimbal Mount 6 Pedestal Sport-Troll Easi-Troll Uni-Troll HP Mini-Magnum Magnum 10 Magnum 20 Digi-Troll IV