Tech Talk: Rudder Nodules

Rambler 88 brims with bleeding-edge design concepts, her rudders, which carry nodules on their lower leading edges—much like those seen on humpback whales’ fins—caught our eye at SAIL
Author:
Updated:
Original:

One of the coolest new builds to emerge from a boat shed in years is Rambler 88, a Juan Kouyoumdjian-designed all-out monohull monster that was completed by New England Boatworks, in Portsmouth, Rhode Island, this past winter. While Rambler 88 brims with bleeding-edge design concepts, her rudders, which carry nodules on their lower leading edges—much like those seen on humpback whales’ fins—caught our eye at SAIL, so we called the world’s foremost foil expert to find out more.

“I believe the nodules do two things, one that has been proven, one that has not,” says Paul Bieker, one of Oracle Team USA’s core designers and a principal at Bieker Boats in Seattle, which has successfully employed nodules on some designs. “The proven effect is an increase of the maximum lift angle of attack, i.e. a more gradual stall. The non-proven effect is the rotating turbulence from the tubercules creating ‘fences’ along the suction side of the foil [on boats with a single rudder], which may delay ventilation.”

Since Rambler 88 carries twin rudders, says Bieker, the primary benefit here is a boat that’s a touch more forgiving on the helm, albeit at a price. “There’s a small drag penalty at normal sailing angles of attack,” Bieker says. “For this reason, I don’t expect nodules to proliferate in grand prix sailing.” Time will tell how they serve Rambler 88.

Related

02-'17-Trans-Atlantic_Downwind-Schralpin

At The Helm: Man Overboard!

Imagine this simple scenario: the boat’s powered up, sailing close-hauled in a building breeze under full sail. I come on deck as the skipper during the watch change to make sure the new crew is comfortable and the boat is properly set up for both the current conditions and ...read more

Promo-01-LEAD-MGR00321

Contrasting X-Yachts & Moody Cruisers

One of the most fascinating things about sailboats is the different ways that sailors, naval architects and builders will approach a single design problem. The result has been a bewildering array of rigs and hull forms over the years, and in the case of the two boats we’ll be ...read more

04-Yacht-anchored-in-front-of-one-of-Lastovo's-gunboat-tunnels-(3)

Cruising Charter to Croatia

As is the case with so much of the Mediterranean, to sail in Croatia is to take a journey through time. Centuries before the birth of Christ, Greeks traded amphoras of oil, wine and grain across these waters. During the first millennium, the Romans built lavish palaces and ...read more

m123728_13_01_171012_PMA_02901_9999

Alicante Announced as an Ocean Race Europe Stop

The Ocean Race Europe, a new event in offshore sailing, will include Alicante as one of four stopover cities. This European offshoot of the former Volvo Ocean Race will include the biggest change to the racing rules under the new title—fully crewed IMOCA 60s will join the ...read more

01-LEAD-doublehanded2

Preparing for a Doublehanded Race

A few months ago we took a look at the development and attraction of doublehanded racing (Two to Tango, June/July 2020). Hopefully, that served to whet your appetite. If so, the question becomes: “How do I get started? The good news, as we explained in Part 1, is that if you are ...read more

01-LEAD-Day-three---dolphins.-300-dpi

A Key Approach to Passagemaking

How you approach offshore sailing is key to the success of each passage. In addition, some of the most valuable, even crucial attitudes and skills may not be either learned or valued in everyday life on shore and may even fly in the face of talents that are greatly admired and ...read more

OceanVoyagesInstitute-2048

Point of SAIL: Mary Crowley of the Ocean Voyages Institute

In this episode of Point of SAIL, Principal Editor Adam Cort talks with Mary Crowley, founder and executive director of the Ocean Voyages Institute, a not-for-profit based in California that has been both educating sailors and working to preserve the health of the world’s ocean ...read more

01-Ocean-Voyages-Institute_PHOTO-READY_1_pg

Tracking and Catching Plastic Waste

Plastic waste—in the form of everything from plastic soda bottles to abandoned fishing nets—constitutes a major threat to the health of the world’s oceans. Giving the immense size of an ocean, though, actually finding all the plastic floating around out there in a time-efficient ...read more