Hawaii & WashingtonJul 2, 2014 02:50 PM
Hyak adapts a familiar ocean-towing design for boats chartered to Crowley
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The bow staple.
“And this design hits the sweet spot at 91 U.S. regulatory tons and 497 International tons,” said Dorn. “Under 100 U.S. tons keeps the required crew complement at a potential of four, an enormous labor cost savings.
“The boats are SOLAS IMO qualified, but staying under 500 International tons means the boats are not required to have separate generator rooms or a motorized lifeboat and a number of other things. They can go anywhere in the world.”
Dorn and Smith intend for Hyak to become the go-to company for long-term bareboat charter and for their Titan class to be the tugs of choice for ocean towing. “We don’t want to compete with our customers, so we’re not building the boats to operate ourselves, but to lease out,” Dorn said.
At sea trials in June 2013, Hawaii’s bollard pull was measured at 82.5 tons. It had a free running speed of 14.5-knots. The performance exceeded the partners’ expectations for pulling a loaded 420-foot barge at 10-knots, and confirmed for them that the fuel efficiency of a 4,000-hp boat was realized in a 6,000-hp tug.
The GE four-stroke, medium-speed engine is 18 percent more fuel efficient than a similar horsepower four-stroke, high-speed engine, according to Dorn. Unlike the standard propulsion package of two-stroke, medium-speed mains, the GE consumes no lube oil. Compared with the tugs in the Sea Coast and Sirius fleets, Dorn contends that the savings on fuel and lube oil in the new tugs are significant.
The 20-year maintenance schedule on the GE engines indicates 40,000 hours before needing a top end first inspection. “That’s six or seven years for most line-haul operations,” said Dorn. “I’ve heard from Crowley that they are burning 1,500 gallons less fuel per day compared to the last generation of line-haul tugs. And they’re not using much lube oil.”
Brandon Durar at JonRie has been working closely with Dorn on the Titan tugs to redesign the winch systems for ocean-class towing. For boats that operate at sea and are therefore unreachable for repairs, the primary modifications to the winches are independent operation and redundancy, a system that Durar has dubbed JonRie unclutched.
One of the two four-stroke, medium-speed GE 8L250 engines. They generate a total of 5,358 hp at 900 rpm.
“To that end the Series 500 double-drum towing winch on the stern has independent towing drums,” said Durar. “If anything happens to one drum, the other has its own motor and any job out in the ocean can be completed.”
Each drum is also powered independently, utilizing pumps on each of the John Deere 6081 Kohler gensets, creating redundancy in case of a pump failure.
“When both pumps are clutched in, they will produce 400-hp of power to the winch producing extreme speed and line pull,” Durar said.
The winch also features a controlled free-wheel system that allows the operator to pay out the line as quickly as necessary and then feather it back. The drums are wound, one with 2,400 feet of 2.25-inch wire, and the other with 1,800 feet of 2-inch wire.
On the bow is a JonRie Series 200 hawser winch, also independently powered, and wound with 600 feet of synthetic line.
All of the operations for both winches can be operated safely from the pilothouse. “The level wind on the towing winch is also an independent drive, so no one has to be on deck to make adjustments,” said Durar. He added that the level wind can be operated in auto mode to synchronize the line on the drum with the winch’s joystick. Or you can run it manually. It has the ability to move back, forward and be stopped as you spool against the flange.
Carbon fiber shafts and couplers connect the engine to Schottel 1515 FP z-drives. During sea trials Hawaii’s bollard pull was measured at 82.5 tons.
The unclutched ship set supplied by JonRie includes the independently powered capstan that can be engaged whether or not the other winches are in use.
Greg Armfield, co-owner of Schuyler Rubber, reported that the Woodinville, Wash., company provided its model SR3D-2 double-loop fenders for the main upper bow area and model 100A solid-type fenders for the lower bow and stern sections. As another nod to Western Towboat, a row of rigidly fixed airplane tires line each side of the hull. Dorn, like the Shrewsbury brothers, dislikes the clanking of chain-fastened tires in the night.
Crew safety and retention have become major factors in crewing workboats of late. Recruiting crewmembers is a challenge, and training them is costly, making retention a major goal. Crew comfort is an important factor in that regard, especially in ocean towing where members have to make the tug their home for long periods, in all types of weather.
“We are using the Norax system of insulation in all of the bulkheads, overheads and floors in the living areas,” said Dorn. The panels are sound attenuated and fireproof, and the living area is very quiet. It is the same system as is used on cruise ships.”
The Titan tugs will carry ABS Maltese Cross A1 and Towing Service certifications that will allow them to tow internationally. At Western Towboat, the Shrewsbury brothers’ mantra is “easy maintenance and simplicity,” and they build their boats to last. The Hyak boats, Hawaii and Washington, follow suit. Dorn is confident that Hyak’s goal of adapting the design of Western Towboat’s proven tugs to encompass a broader range of ocean and coastal towing applications has been met.