THE FUTURE OF PROPS
Marlin Magazine

"Right now she's running at about 26 knots, but we still haven't got the prop right. We think we can get a couple more out of her with some adjustments to the pitch."

How many times have you heard these sentiments expressed when talking with a boat owner - or perhaps more often, with a boat salesman? Despite the huge dollars that go into the design and building of high-dollar sport-fishermen, the end result on how the boat performs always comes down to how the wheels harness those thousands of horses into smooth, efficient thrust.

And determining that, it seems, is more voodoo than science. A new computer based calibration instrument developed by Terry Ryan of Australia, however, has brought propeller repair out of the dark ages.

Called Prop Scan ®, this device inexpensively measures a propeller to within 1/1000 inch, and then translates those measurements into graphical models that technicians can use to bring the prop within 2/100 inch of spec. And because the service is computer based, the propeller's profile is saved permanently for future repairs or replacement.

Black Dog Propeller of Solomons, Maryland, was the first U.S. company to take advantage of the new Prop Scan® technology, and was followed in 1996 by Coastal Prop Technology in Fort Walton and Cape Coral, Florida. Four more Prop Scan® shops have popped up in the last year. According to Mark Daily, general manager of Coastal Prop Technology, the shops offer similar services, pricing and policies. And all of them offer prop evaluations for free. "You ship your prop in, and all evaluation, a full set of reports and a complete pricing package - everything up until we pick up the hammer - is free," Daily says. "But out of the 1,000 sets of props we've evaluated, we've never had a customer say he didn't want to fix his props. Once they see the reports showing the inefficiency of their props, they say, 'Do'em.'"

A typical job, says Daily, is a slight tuning of new, off-the shelf propellers with no visible damage. For a 46-footer running 27-inch, three-blade bronze wheels, this type of evaluation and repair would run in the range of $275 per wheel .

Daily is quick to add he's yet to find a dissatisfied customer. "Across the board, 70 percent of our customers gain between 1 and 2 knots, typically a 10 to 12 percent increase in fuel efficiency and absolute elimination of vibration."

** This article partially excerpted from Marlin Magazine.