Canting ballast twin foils

The CBTF system has just been taken up by designers Reichel/Pugh. madforsailing wanted to find out why

Reichel/Pugh Yacht Design recently announced that they will recommended to their clients 'Canting Ballast, Twin Foil' (CBTF) technology, a patent of DynaYacht, Inc. Although this might sound like Open 60 technology in fact the system involving an Open 60-style canting keel and fore and aft-mounted rudders has been under development for 10 years. DynaYacht trialled the system on their test craft Red Hornet, skippered by Peter Isler, and have since licensed the technology to WD Schock Corporation of Corona, CA.

The Schock 40 which has been the result has been causing stir in the States and and in 2001 was Sailing World magazine's Overall Boat of the Year award and won their 'Best Sportboat' and 'Best Innovation' awards. The company now have a 52 on the stocks.

Jim Pugh, one of the designers for the new Team Dennis Conner's new ACC boat, sees the CBTF as breakthrough performance technology and explained why to madfor sailing:

The Problem with a Keel
Traditional sailboats are handicapped by the inherently compromised design of their keel. The keel needs to perform two functions - generate side force to keep the boat from sliding sideways through the water and provide righting moment to keep the boat from heeling over. Unfortunately, as the keel's righting moment increases, it's side force efficiency decreases.

The CBTF Solution
CBTF technology overcomes this by separating these two conflicting functions. The canting ballast is designed specifically to generate the righting moment and the twin foils are designed specifically to generate side force. This new paradigm of sailboat design suddenly offers unprecedented advances in performance and comfort. The canting ballast can now be swung from the centerline of the boat to leverage it upright at a fraction of the weight of a conventional keel. The twin foils can now be placed anywhere on the hull to optimise their side force function. This new technology allows designers to build faster and lighter sailboats that heel less.

The Benefits
The primary benefit of the CBTF system is a lighter boat. We are not talking about a few pounds and ounces, we are talking about cars and trucks. A canting ballast is 50% of a conventional keel. This weight savings allows the designer to do many different things. The best, or at least most fun, is to design an all-out racer. By shaving tons of lead weight off the boat, we can design a line honors or record-breaking yacht. The weight savings also allows the designer to put a more luxurious interior in the boat while maintaining a performance advantage. Future variances on the design include shallow draft canting ballast...

How it Works
The ballast system is controlled by a push-button electric hydraulic ram. The ballast can swing up to 55 degrees off of centre line providing incredible righting moment leverage while keeping the VCG much lower than water ballast. The foils provide the side force and steering and are controlled electronically or through a line system. They are linked directly to a conventional steering system and work automatically.