A Nor-Tech catamaran boat powered by twin 850 SCi sterndrives. Photo credit. Florida Powerboat Club.
The boys from Sunsation enjoy their time on the water. Photo credit: Naplesimage.
With Spring in the air, the timing is right to review the basics of high performance boat operation to ensure you and your passengers have a safe and enjoyable Summer on the water. We include a Guide to Hi-Performance Boat Operation with every engine we ship. We encourage new and current owners to review the book and then get some in-boat driving lessons from your local high performance dealer. Those who do not have a qualified driving instructor in their area may want to consider Tres Martin’s Performance Boat School.
Our operation guide is packed with general performance boating information including a list of descriptive terms relating to propellers, hull types and overall boat performance. Let’s first review the various performance boat hull configurations.
Vee-Bottom
View of a traditional vee-bottom hull.
Good view of a vee-bottom hull running is rough water. Photo credit: Naplesimage.
The traditional vee-bottom is the most common hull design. It offers good speed and a softer ride, especially in rough water. The softness of the ride depends on the angle of the “V”, called deadrise, radius of the keel line and the use of strakes. If your boating is mostly in larger bodies of water such as the Great Lakes or open seas, you may want to consider a boat with this hull type. The most recent change in this design over the past decade has been the incorporation of strategically placed notches or steps in the hull. The steps create air bubbles, raising the hull off the water on a drag-reducing cushion.
Can't get a better example of "riding on the pad" than this.
Vee-bottom hull with pad.
Some vee-bottom hulls feature a small flat area toward the rear of the keel called a pad. Similar to steps, the pad reduces the wetted surface area the hull runs on, increasing top speed with minimal affect on the ride quality. Mercury Racing offers a full-array of outboard and sterndrive propulsion options for the vee-bottom boater.
Tunnel
The outboard tunnel race boat hull design.
Shaun Torrente slams his F1 tunnel race boat through a turn. Photo credit: Paul Kemiel Photographics.
Outboard tunnel boats are the fastest turning race vehicles on earth. The sharp, 90-degree transfer where the tunnel sides meet the bottom of the sponsons helps the boat settle in the water as it enters a turn. The submerged sponsons make the boat turn as if it were on rails. It is common for drivers to experience 4-1/2 to 5Gs as they enter a turn at 120 and come out at 90+ mph. Obviously, only experienced racers should be considering this type of hull. Power options for outboard race tunnels include the Mercury 60 EFI FormulaRace and OptiMax 200XS SST.
Catamaran
Outboards are popular power source for catamarans.
525 EFI powered Talkin' Trash Super Cat Lite race boat. Photo credit: Paul Kemiel Photographics.
I like to refer to catamarans (or cats as they are often called) as tunnel boats on steroids. The design principal is similar. The boat rides on two sponsons or hulls separated by a tunnel. Air entering the tunnel generates lift as speed increases.The wetted surfaces and hull drag are reduced, for enhanced speed and ride quality. This design is not for the novice operator. The air entrapment hull is sensitive to engine trim, wind, and water conditions. In general, they produce a smoother and faster ride over a vee-bottom in calm to mild chop. The vee bottom is king in rough water. The fastest cats on the water today are powered by the venerable 1350 sterndrive. Our OptiMax 300XS is popular choice for those who choose outboard power for entry into the cat experience.
In Hi-Performance Boat Operation – Part 2, I will review the important things to consider when preparing your new Mercury Racing outboard or sterndrive powered boat for the upcoming season.