Page 29: of Maritime Reporter Magazine (August 1996)

compensated for by the reduced cost and maintenance of an inter- nal belt. The transfer system is able to achieve a steady 2,000 tons/hour offload speed.

Bottlenecking at the transfer point is always a worry during offload- ing.

To facilitate smooth operation, infrared cameras located in the tunnel and at all transfer points, including the end of the boom, allow operators to monitor belt loading conditions from the pilot- house.

By eliminating shutdowns due to receiving hopper overfills, jammed products, or belt overloads, the sys- tem is designed to easily match the receiving capabilities of most ports. Mr. Sridhar estimates the improved delivery system will save valuable time in port, and, accord- ing to Mr. Jones, the system will "enable the crew to focus on system maintenance instead of operation."

Delivery system

Another new design feature, a 250-ft. (76-m) telescoping boom at midship, capable of 270 degree rotation, is designed to allow for greater flexibility in delivering cargo to onshore hoppers. A hydraulic actuator slews the boom.

Siemens produced a design in which the actuator remains sta- tionary while the boom rotates, propeller-style. The luffing, slew- ing and shuttling action of the boom are all hydraulically con- trolled.

According to Mr. Sridhar, "The biggest challenge of this job is the hydraulics. For hydraulics to work we need the electrical, because it all requires a 20-milliamp control signal, and that's what Siemens controls." The two companies worked closely on the control phi- losophy. Seabulk set forth the sys- tem requirements and Siemens developed the hardware and soft- ware utilizing PLC technology.

Environmental improvements

As more urban ports deny dock- ing permission to bulk carriers due to dust and noise pollution, CSL wanted a system that would elimi- nate these restrictions. To ensure these requirements, Seabulk replaced the standard open-lattice boom with a completely enclosed boom system to contain airborne pollutants. Even the belts within the body of the ship are covered to reduce dust in the internal envi- ronment. Additional dust extrac- tion equipment is integrated into the system throughout the ship, improving air quality for crew members.

Vibration damping on all the dri- ves helps with noise suppression.

The boom chute has a lining of sand between the inner and outer walls for additional noise abate- ment. An indirect benefit of care- ful regulation of product flow is that by eliminating overflows, pol- lution from spilled product is no longer a problem. With these safe- guards in place, these vessels will reportedly be able to unload in any port, even congested urban loca-

August, 1996 tions, without dust or noise.

Selling the idea

Mr. Sridhar presented his design to CSL International in

Boston. To prove it would work,

Seabulk built a $850,000, full-size prototype consisting of one com- plete cargo hold/hopper and con- veyor. They tested gypsum in the prototype and were able to demon- strate the 2,000 tons per hour flow rate.

CSL has purchased exclusive rights to the design for a four-year period. It currently has three ships underway at the Jiangnan

Shipyard in Shanghai, China. Two of these vessels are for CSL

International, and the third is for

Egon Oldendorf.

The Seabulk engineer onsite dur- ing construction, which is sched- uled to begin in October, will be

Brian Carefoot. Seabulk subcon- tracted the fabrication of the boom and the feeder gates back to

Jiangnan.

Other vendors include Siemens, supplying the electrical control system; Flenders, supplying the gearbox and reducers; Continental

Conveyors of Toronto, Ontario, in its first marine project, supplying idlers and pulleys; Fox Fluid Bar of

Toronto supplying the hydraulic actuator; and the Walz & Krenser firm in Rochester, N.Y., designing and supplying watertight doors.

The unnamed vessel's first cus- tomer is New England Power. It will carry coal to New York in the spring of 1998.

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