By Bill West, contributing editor
The decision to repower a vessel is a multi-faceted one, and it can be safely assumed that no two decisions in this arena are exactly the same. Whether it's a crewboat that needs new power units to accommodate a new scope of operation; extending the life of an old, but otherwise stable boat; a rip and refit to replace under performing engines; or as a simple factor in the overall vessel conversion equation - the decision to install new engines on a vessel entails a significant financial investment for the owner. This year has seen a number of significant and unique marine repowerings. The vessels covered in this report are unique in that they range from a 149-passenger tour boat to an 846-ft. long military freighter powered by gas turbine engines.
Also unique is the extent of the work mandated for each vessel, as repower jobs often require a well-thought engineered solution for matters from determining the best mechanical solution to physically getting the old unit out and the new one in.
USNS Lance Corporal Roy M. Wheat
Certainly the largest, costly and most complex of these four projects is the USNS Lance Corporal Roy M. Wheat. This vessel has been at Bender Shipbuilding and Repair for the last four years and because of its size the ship has become almost a permanent landmark on the Mobile, Ala. skyline.
The 746-ft. by 98-ft. vessel was built 14 years ago in the Ukraine as a RoRo freighter.
Purchased in 1997 by the Military Sealift Command, the vessel is slated to become a part of MSC's Maritime Prepositioning Force carrying enough equipment and supplies to equip a marine division.
After arrival at Bender, the freighter had a 118-ft. midbody section added and since then the vessel has been significantly upgraded including replacement of its original Ukrainian gas turbines with upgraded engines by the same manufacturer, Zorya Production Associates.
These engines are heavy-duty marine grade gas turbine power plants that operate similarly to aircraft engines. The engines produce 18,000 hp each. Because gas turbine engines produce great amounts of waste heat, this heat is used to fire steam turbines that also connect into the reduction gear producing an additional 5,300 hp per shaft. The total hp of 23,300 per engine can propel the fully loaded freighter to 24-27 knots.
Several other power plants on the ship were either overhauled or replaced. Wärtsilä overhauled the bowthruster powered by a Wärtsilä engine at its Ft. Lauderdale facility. A Kamewa stern thruster was added driven by a 650 kW electric motor. The project also called for reworking three diesel engine gensets powered by existing Sulzer engines. New KATO Engineering generator front ends were added to these three gensets. To meet added demands for electrical power due to increased air conditioning and ventilation loads, a pair of Caterpillar 3516B gensets was added to the ship, each generating 1,825 kW of electric power. Rounding out the power needs of the Roy M. Wheat is a Caterpillar 3508B producing 850 kW of emergency power.
The vessel is one of a very few that utilizes the four main methods of ship power…steam, electric motor, diesel engine and gas turbine. The vessel is due to be completed by the end of the year at a cost of over $134 million. This project represents Bender's largest single ship contract.
It also represents a significant achievement for Bender. For example vessel documentation was in Russian that had to be translated. Bender's Engineering Department had to totally reengineer much of the vessel since it was changed significantly with the addition of the midbody section and other additions such as the topside forward and aft enclosed "houses" to store additional cargo. Asbestos had to be removed from sections of the ship using special abatement procedures. The finished product represents not only a repowered ship, but almost a new ship.
Seacraft Shipyard, Amelia, La., specializes in rebuilding, converting and repowering crew boats. Some of the vessels remain as crew boats, but some of their projects evolve into vessels with a totally new mission, operating far from the Gulf of Mexico
. Such is the case with the Victory Rover.
The Victory Rover was formerly a crew boat that performed decades of service in the Gulf of Mexico
for a major operator of oil field supply services transporting rig crew, cargo and vital drilling fluids to offshore oil platforms.
Today the Victory Rover is a tour boat offering passengers sightseeing trips around the Norfolk, Va. Navy Base. The vessel can hold 150 passengers. The vessel was repowered with three Detroit Diesel 12V71 engines driving Twin Disc gears turning four-blade propellers giving the vessel a cruising speed of 20 knots.
Two GM 3-71 engines power a pair of 30 KW Delco generators.
The main deck of the boat has an enclosed climate controlled cabin with aircraft type and lounge seating. The main deck also has a snack bar and two heads. An open second deck offers unrestricted visibility with an aluminum canopy partially covering this deck.
Crew boats are ideal vessels to convert to 149-passenger sightseeing and luncheon/dinner craft. Typically these vessels have open main decks aft of the forward superstructure that formerly was used to haul cargo. Adding an aluminum cabin to this deck is easier than having to remove an existing cabin or superstructure. In addition there is usually plenty of room below decks for the addition of air conditioning equipment and other mechanical devices. Often below deck spaces are used as heads, offices, crew lounges. To lighten the vessel, tanks used to haul drilling water and fuel to rigs are often removed if that space can be profitably used.
Seacraft has made a specialty of converting crew boat hulls to other uses. They also build and renovate dive boats and other steel and aluminum vessels.
Tidewater's 180-ft. supply boat Secretariat was built in 1980 and proved to be as much as champion in the Gulf of Mexico as her famous namesake did on the race track. Retired to Bollinger Shipyards' Safe Harbor at Larose, La., in 1995, the vessel was not expected to return to work in the Gulf.
But with day rates for supply boats in the Gulf at historic highs, North American Ship Holding Company, Inc., Borg, La., bought the vessel and moved it a few hundred yards to Bollinger's Larose repair yard.
North American Ship Holding studied the "buy new" versus "renovate old" equation and found that they would be both dollars and time ahead by renovating Secretariat. Time is definitely money with day rates for supply boats at $7,000 per day.
Repowering was a major part of the cost of renovation, but as in the other vessels examined, certainly not the only cost. Returning a 20-year-old supply boat to Coast Guard standards required a thorough and rigorous examination of every component of the vessel.
The repowering was accomplished with the removal of old engines and replacement with new Caterpillar 3508 power plants and Twin Disc gears. Engine foundations had to be modified, new Fernstrum grid coolers added and new wiring, fuel and exhaust piping connected.
Other major renovation items included cleaning, blasting and painting of all mud, ballast and fuel tanks on the vessel, replacement of the pilothouse and its electronics, new crew quarters, new heads and a reworked galley. Rudders and shafts were removed while the vessel was on dry dock and reworked and reinstalled. All of the electric motors and pumps were either reconditioned or replaced. A project of this magnitude needs the resources of a major shipyard such as Bollinger. Work was done on two shifts and the vessel was put back to sea in 70 days.
Ferryboats almost always work in totally obscurity. That is especially true for state operated ferry systems that cross rivers or channels on equally obscure highways.
For 37 years, the Cameron II crossed the 1,550-ft. Calcasieu River/Ship Channel in southwest Louisiana with little fanfare. The 200 x 50 ft. double ended ferry vessel carried 28,000 vehicles a month operating 24-hours a day.
Late last year the vessel was sent to Conrad Industries, Morgan City, La., for what was thought to be a series of well-defined repairs. As often happens, once the vessel was in the shipyard, it became obvious that much more had to be done to the ferry than the State of Louisiana originally anticipated. For example, most of the wiring in the boat had to be replaced, rather than just in specific areas. Hull thickness in some places was inadequate, so hull patches had to be added. New hull bulkheads had to be added.
In the propulsion area, the state thought they could rebuild the four engines powering the thrusters and the two engines running the generators. Reagan Power of Baton Rouge, La., showed that new engines would be much more efficient.
Reagan supplied four 235 hp John Deere engines that operated the thrusters through Twin Disc PTO's. Also they replaced the two existing engines powering the gensets with new John Deere diesels running 96 kW generators by Newage. Reagan Power sold the removed engines and credited the State with the funds from that sale.
One unique aspect of the repower job was that the state reconditioned the thrusters ... one of the few states that has the capability to do such work. As with many old vessels, interiors needed considerable work in the pilothouse, heads and crew spaces. Mark Robicheaux, Inc., of Morgan City did this work for Conrad.
Many of the problems encountered with this repower and renovation were solved onsite by the engineering department of Conrad Industries and by Repair Manager Jim McElroy.
The one constant theme flowing through these four repair stories is the engineering talent and ingenuity of the shipyard management and their craftsmen.
The repower and renovation of a vessel is an art unto itself. Often there are no set specs or blue prints. Typically the vessels come into the yard with only a small fraction of the work to be done well defined. Only after the vessel has been thoroughly inspected by shipyard personnel does the owner realize the real magnitude of the work to be done.
These four mini case studies are representative of repower and renovation projects completed so far in 2001. They represent vastly different size vessels that work in varied segments of the marine industry. The key to all renovation and repower projects is the innovation and creativity of the shipyard. They make the vital difference between a project that "works" and one that does not.