The Unlimiteds are built using aircraft construction techniques with composite materials, and each boat is one of a kind. From the 1950's through the 70's and into the 80's, World War II aircraft engines were the powerplant of choice. Lately, helicopter turbine engines are used by all but one team, the father/son owned Cooper U-3 which continues to set piston-powered lap speed records.

Once a hydroplane comes up to speed, it "hydroplanes" on top of the water using airflow beneath the boat to decrease the boat's drag on the water. Hydroplanes fly more than they float, with the perfect 'stance' being just half of the prop in the water, and a square foot or less of water contact on the two forward sponsons. This type of boat design is often called a "three-point" or "prop-rider" hull.

Sometimes a boat will catch too much air and do a breath-taking backflip called a "blow-over". Recent improvements in the safety of Unlimited Hydroplanes has saved the lives of numerous drivers. The most notable advancement has been the use of modified military aircraft cockpits to secure the pilot in a watertight capsule. While the cockpit itself has not survived all crashes, until recently all of the pilots have. Sadly, George Stratton was our first loss since Dean Chenoweth [1982] during testing at the San Diego race in 2000. As a result, teams continue to strengthen their cockpits.

1. Airtrap - An extension of the inside wall that forms the boats tunnel [see #19]. Changing the length of the airtrap changes the hull's ride.
2. Cockpit - The ultimate in captain's chairs. This is a modified, watertight jet aircraft canopy.
3. Deck - The upper surface of the hull.
4. Engine - The motor that drives the boat, usually a Lycoming turbine engine from Vietnam era helicopters.
5. Air intake - Covers the engine and improves the hull aerodynamics.
6. Nontrip chine - The vertical surface of the hull that is inclined to aid in cornering.
7. Nose Cowl - Its aerodynamic shape deflects the air around the cockpit and engine compartment.
8. Propeller - Also called a 'prop' or 'wheel'. The propeller is the only force that moves the boat. Most have 3 blades and are only about 14 inches in diameter.
9. Prop shaft - Transmits power from the engine to the propeller.
10. Rudder - A vertical blade mounted on the transom that sticks down into the water and provides steering control for the boat.
11. Runner - The surface that touches the water at the bottom of each forward sponson.
12. Shaft Log - A pipe-like unit that passes through the bottom of the hull. The Prop Shaft rides inside the Shaft Log, between the engine and prop.
13. Skid Fin - The blade attached to the left sponson. It keeps the boat from sliding to the right during a turn, and makes for very fast and stable turning.
14. Canards / Slats - Adjustable flaps on the leading edge of the deck. They change the airflow over and under the hull, which in turn changes lift.
15. Sponsons - The two pontoon-like parts of the front of the hull.
16. Strut - The rear bearing housing for the prop shaft.
17. Tail Fin - The vertical pieces that support the wing and provide directional stability.
18. Transom - The vertical surface at the rear of the hull.
19. Tunnel - The space underneath the hull's center section. This constrains the cushion of air on which a hydroplane travels.
20. Wing - The horizontal airfoil that helps stabilize a boats attitude.