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Fort Ripley

Nov 5, 2014 12:48 PM

Handling multiple missions with a compact footprint

Courtesy C. Raymond Hunt Associates/Peter Boyce

Jack of all trades, master of none. When building a boat for multiple missions, it’s a label that can be hard to avoid. You may be able to shimmy all of the pieces into place, but will the final product deliver for all concerned when it finally hits the water?

That was the challenge presented by Southeast Ocean Response Services (SORS) of Charleston, S.C., which wanted a vessel with a varied pedigree — one that could handle salvage support, firefighting, piloting and supply duties, all in a footprint of less than 65 feet with the ability to run quickly offshore.

The result is Fort Ripley, a 64-foot fast response boat designed by C. Raymond Hunt Associates of New Bedford, Mass., and Gladding-Hearn Shipbuilding of Somerset, Mass., which also handled construction. The all-aluminum boat is one of the first commercial vessels in the United States to be powered by Volvo Penta IPS (inboard performance system) drives, steerable pod units with dual forward-facing, counter-rotating propellers.

John Cameron executive director of the Charleston Branch Pilots Association, inspects Fort Ripley at Gladding-Hearn in Somerset, Mass.

Allegra Boverman

“This is sort of a new class,” said Peter Duclos, president of Gladding-Hearn. “I don’t think you’re going to see every pilot organization in the country building a boat like this — it’s a pretty different animal for sure. It’s going to be a great pilot boat, but it’s not purebred like our other ones where you have only one mission in mind, just to get a pilot on and off a ship safely. This has a lot more capability.”

Fort Ripley is the first boat delivered to SORS, founded in 2011 as a sister company of Charleston Navigation. Both companies are owned by the Charleston Branch Pilots Association. While the boat will be used primarily to provide offshore response, it also will be added to the rotation of pilot boats in the harbor when it is available.

The idea for Fort Ripley — and its design — can be traced to Coast Guard requirements for chemical and oil tankers to have contingency assets within 50 miles of ports of call in the U.S. John Cameron, executive director of the pilots association and president of SORS, said a boat with the necessary capability didn’t exist in Charleston before Fort Ripley.

“We were looking at these new rules recognizing that there just isn’t a workboat capacity around here that can break off from what its primary role is — assisting in docking vessels, for example — and really be on call to go out up to 50 miles offshore and deliver (damage) surveyors, a dive prepare team or a firefighting team,” Cameron said. “So we went to Gladding-Hearn and said here are these readiness requirements to cover a handful of ports from Morehead City (N.C.) to Jacksonville (Fla.).”

The layout of the wheelhouse, left, provides easy access to controls.

Allegra Boverman

The requirements involved calculations for delivering personnel and equipment up to 210 miles from Charleston for damage assessment, firefighting and repairs. The variables of time, range, speed and payload were all governed by a constant: How much can you fit in a 64-foot, 11-inch boat?

“Sixty-five feet is a common regulatory boundary,” Cameron said. “One of the most applicable rules when you’re signing up to be in the response business is a speed restriction. The right whale rule (restricting speed to 10 knots or less in certain areas at certain times of the year) applies over 65 feet. Throughout the development of that rule, we had asked whether commercial emergency response would have any exemption from that rule and it didn’t seem likely. So if all the capability could be fit in a vessel that wouldn’t be speed-constrained, obviously that was the simplest solution.”

Enter the IPS. Duclos said originally the idea was to go with waterjets, but because of the length limitation it was going to be hard to give the boat enough power without making it too heavy.

“It has to have a lot of fuel because it needs a lot of range,” he said. “It needs speed — it has 30-knot capability loaded with fuel and deck equipment. After a lot of work, we determined that the best propulsion system was the Volvo Penta IPS.”

Fort Ripley has three Volvo Penta IPS drives with forward-facing propellers. They pull the boat through the water rather than pushing it.

Courtesy Volvo/Andrew Pelton

Fort Ripley has three IPS pods, each powered by a Tier 3-rated, 700-hp Volvo D13 diesel. The center engine drives a 3,500-gpm Hale fire pump that supplies water to a pair of monitors. The two outer engines counter the thrust of the water and maintain the boat’s station with the aid of dynamic positioning. Engine speed and pod steering are controlled by three joysticks, one on the wheelhouse console and two at aft docking stations. 

Duclos said the IPS system saves on weight and space, providing extra room on the boat for fuel and accommodations. It is also about 30 percent more efficient than waterjets.

“Basically we’re doing with 2,100 horsepower what it would have taken about 2,800 horsepower with waterjets,” he said. “We use a lot of waterjets (at Gladding-Hearn), but for this application IPS was better. Had we gotten rid of that 65-foot limit, had that not existed, this probably would have been a jet boat.”

A Palfinger knuckle-boom crane reflects Fort Ripley’s multi-mission capability.

Allegra Boverman

Winn Willard, vice president of C. Raymond Hunt Associates, said the length constraint was also a factor when it came to designing the boat’s hull. Fort Ripley’s multiple roles again required an approach to accommodate speed and load capability.

"It’s a planing hull, and as in all planing hull designs it comes down to kind of a weight versus bottom area equation, so that you have enough planing area to carry the load efficiently,” he said. “It’s not unlike an airplane design where you have to have enough wing to fly the passengers. If you had the freedom to make it longer, you can add more boat and bottom to carry the load, but we had to work within 65 feet.”

The solution was to add to the beam. Willard said designers had to be careful not to make Fort Ripley too wide, though, “because then you get a boat that isn’t a good sea boat, it’s fat. But we’ve done so many boats over the years, 50 years’ worth of planing hulls, that we have pretty good numbers on which to base our predictions and calculations.”

Duclos said the boat also has a Humphree Active ride control system with interceptors — “they’re like trim tabs” — to reduce pitch and roll on the open ocean.

Recessed steps in the transom lead to a platform for divers. There is another platform atop the wheelhouse for pilots. 

Allegra Boverman

Up on the deck, Fort Ripley’s features include a knuckle-boom crane aft of the main cabin. Below deck is a forecastle with a galley and dinette, a head and separate shower, and four berths. Air conditioning is provided by a 96,000-BTU seawater-cooled system.

After successful sea trials in August at Gladding-Hearn, Cameron said Fort Ripley quickly proved its worth off the coast of Charleston.

“The boat operators have been very impressed with its handling characteristics in seas and alongside ships,” he said. “The fuel economy has been very good. The systems on board have all exceeded our expectations. We’re really very happy with the boat.”

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