Unlimited 3 Point Hydroplane 
In common usage, the word "hydroplane" usually refers to a three-point. A three point hydroplane has two planing surfaces forward and one aft. The forward points (sponsons) are lower than, and are outboard, of the main hull. The third point is the aft end of the boat and is generally flat. Hydros use aerodynamics to force a cushion of air beneath the boat and at full speed only the front sponsons and the rear of the boat should be touching the water. At high speed the third point is virtually free of the water and the boat is riding on the surface piecing prop. Hydroplanes require relatively calm water to run well and are not intended for offshore conditions. 
Wetted area footprint of a typical 3point hydro hull. When setup correctly the CG of the boat should be approximately 2- 3" from the back of the sponsons producing this footprint when at full speed. The exact CG will vary depending on the design of the hull.
 3pt and rigger Hydros do not like to turn because they have so little hull in the water which leaves no fulcrum for the rudder to act against. To help compensate a turn fin is added to the back of one of the sponsons. I use the right sponson, some use the left, probably no right or wrong answer here. My theory is since we run in right hand ovals the right sponson turn fin keeps the right sponson pinned to the water. The turn fin should also be slightly angled to prevent it from lifting out of the water during a turn, the angle helps to force the sponson down onto the water surface.
Rigger 
Outrigger Hydro - In general, the Outrigger tends to be the fastest hull type. It is a variant of the basic hydroplane but the Outrigger Hydro has no real corresponding full scale race boat to draw from; it is purely a result of modelers ingenuity. Instead of scale looks, the Outrigger is basically a rectangular tub in which the motor, radio, and other components are mounted, with two sponsons mounted on "booms" near the front of the boat.  Wetted area footprint of a typical rigger. At full plane, the boat rides upon 3 points: the rear sections of the sponsons and the rear of the tub. Outriggers need fairly calm water to stay on plane well. As a rule of thumb locate the CG about 15% the after plane length. The after plane length is the distance from the back of the sponsons to the transom.
Tunnel 
Tunnel Hull - The Tunnel Hull has two sponsons that extend the entire length of the boat, causing a cushion of air to be trapped beneath the boat. Tunnel Hulls tend to be powered solely by outboard engines, because of space restrictions within the hull.  Wetted area footprint of a typical tunnel hull. When setup correctly only the back of the sponsons will be touching the water producing this footprint when at full speed. During a turn considerably more will be touching the water as you slow down to avoid blowing over.
Catamaran 
Catamaran - A Catamaran hull is a cross between a Deep-Vee and a Tunnel Hull. It shares most of the rough water handling capabilities of a Deep-Vee, and has the same general sponsons layout as a Tunnel Hull, allowing high speeds on calm water. Because the hull configuration of a cat gives more room for component placement, catamarans can use either inboard or outboard power plants. The modern catamaran, mostly referred to as a "cat", has twin hulls for planing, side by side, separated by a tunnel or open area. As with other tunnels hulls, air is forced underneath and provides lift to the boat, reducing water drag and increasing speed.  Wetted area footprint of a typical catamaran and stepped catamaran hull. When setup correctly the CG of the boat should be 25-30% back from the transom producing this footprint when at full speed. | 
