A low-tech option in the joystick era

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The articulated rudder eases the challenge of maneuvering a trawler in close quarters

Most boaters are comfortable operating in open water, but low-speed, close-quarters maneuvering can present challenges. For those of us with single-engine prop/shaft-driven boats and no thrusters, the challenge can be substantial, especially when fighting wind and currents.

An articulated rudder is a relatively low-tech item that can greatly enhance your steering control during close-quarters maneuvering. Articulated rudders of one form or another have been around for more than 100 years and until recently were found primarily on large commercial vessels and tugboats.

A conventional rudder is basically a pivoting flat plate suspended vertically from the bottom of the boat. It works by deflecting water flow. When the wheel is turned, prop wash flows past the rudder, increasing pressure on one side and reducing it on the other. The stern moves toward the low-pressure side, and the boat turns. However, a conventional rudder is ineffective when swung beyond 45 degrees to either side of center because the water flow spills around both ends of the plate, impeding headway without providing vessel control. This is called stalling the rudder.

An articulated rudder has an additional plate assembly that extends from the aft edge of the rudder plate (picture the flap on an aircraft wing). This

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additional assembly, sometimes referred to as a fish tail, increases the rudder’s effectiveness at high angles and low vessel speeds by redirecting the thrust at a more acute angle. Typically, a rudder is limited to an arc of approximately 70 degrees — 35 degrees on each side of center. The articulating plate can incrementally add between 20 and 50 degrees of deflection without stalling the rudder.

With the articulated rudder turned hard over, the prop wash can create side thrust similar to what you would experience with a stern thruster. The boat should be much more responsive in a following sea, as well. The aft plate’s operation is automatic and requires no external power. The control is a result of linkage geometry and pivot location, all of which are designed for the particular application.

Several manufacturers offer articulated rudders, including Bayview Engineering Industries of Oak Harbor, Wash. Jamie Wells, a partner in the company, says around 70 percent of its business is with recreational boats from 30 to 60 feet. In fact, BEI’s articulated rudder is a factory option on the new Nordic Tug 54, and the company also has retrofitted Kadey-Krogen and Nordhavn trawlers. Wells says many of BEI’s clients are owners who take delivery of the standard rudder setup and aren’t pleased with the handling characteristics. He says the company is currently working on a Bertram 40 — a twin-screw planing boat — and Mainship 390 for individual clients.

Ben Wilde of Wilde Yacht Sales, a Nordic Tugs dealer in Essex, Conn., has spent a good bit of time experimenting with a BEI articulated rudder on the Nordic Tug 42. Last fall, Wilde took the boat to Cuttyhunk, Mass., and attempted to locate a mooring for the evening. As is typical for this destination, moorings were scarce, and Wilde had to maneuver between moored vessels.

“If the boat had twin engines, I would have been constantly shifting gears, starting and stopping to maneuver,” he says. “With the articulated rudder, I could just steer. The Nordic 42 turns on a dime. It feels like it spins and turns in its own length.”

Intrigued, I inquired about retrofitting an articulated rudder on my 36-foot Albin trawler. Wells walked me through the procedure. The company contacts the vessel manufacturer to secure original rudder drawings, a hull profile, tiller arm length and hydraulic cylinder information. After creating the design drawings and checking the rudder torque calculations, an entire new rudder assembly is manufactured from either stainless or mild steel. The time frame varies with each job, depending on what information is readily available from the builder.

BEI has completed several rudders for the Nordic Tug 37 and 42. A new order for one of those units, within its normal production schedule, would take about a month from start to finish, although Wells says that if a client needs a more timely delivery, BEI can cut that time in half. The approximate cost of the stainless steel articulated rudder (around 7 square feet) for my Albin 36 would be $3,500 ($1,000 less for mild steel). Whichever material is chosen, all contact surfaces and wear parts are fabricated from stainless steel, with bearing and slide points made of Delrin.

The installation isn’t difficult and can be done by most boatyards. BEI also can help the yard work up a realistic cost estimate. As a point of reference, the installation on a Nordic Tug 37 takes about a day. Wells says the installation may be a bit intimidating for the average do-it-yourselfer, though several boat owners have completed the work themselves. I’ve reviewed an installation manual for BEI’s articulated rudder, and I’d do the installation myself with the knowledge that, should I need guidance, it’s a phone call away.

Keep in mind that the helm is going to feel different on boat with an articulated rudder. Where you would normally need 3/4 of a turn on the wheel, you’ll only need 1/4 of a turn for similar vessel response. Wilde says the physical effort needed to operate the wheel increases slightly as vessel speed increases. Wells says clients may need to upgrade certain factory steering system components, such as the hydraulic ram, to provide the same light feel they are used to when steering. He says most factory steering systems are suitable for the installation, but owners may prefer more power assist.

With today’s trend toward large multiple engines, pod drive systems, joystick-controlled sterndrives, and bow and stern thrusters, I wonder how those of us with more traditional setups can survive? The articulated rudder has survived the test of time and is a viable solution that enhances vessel handling and maneuvering without breaking the bank.

For additional information on articulated rudders, contact Bayview Engineering Industries at (360) 675-5300 or visit www.bayviewengineeringind.com