Page 8: of Maritime Reporter Magazine (August 15, 1973)

Sun Ship Delivers Deep-Ocean Mining Vessel

The Hughes Glomar Explorer may be conned from either the forward or aft bridge. Under normal operating con- ditions, the mining ship will be conned from the forward bridge while under way, and from the aft bridge while mining.

The Hughes Glomar Explorer, a prototype deep-ocean mining ship owned by the Summa

Corporation, recently departed Sun Shipbuilding and Dry Dock Co., Chester, Pa., following the shipyard's delivery of the vessel to Global Marine,

Inc. of Los Angeles, Calif., who will operate the ship for Summa. Sun's delivery of the vessel brought to a close a new ship construction pro- gram that was heavily engineering oriented. The fundamental engineering concepts for the vessel were supplied by Global Marine. Global Marine engineers, working in conjunction with Sun engi- neers, refined the plans before actual construction began. A major result of this engineering team- work was the decision to increase the size of the deep-ocean mining ship.

The top of the deep-ocean mining ship's derrick is lifted into position by Sun Ship's floating derrick barge.

The Hughes Glomar Explorer, a 36,000-ton ex- perimental mining ship, has an overall length of 618 feet, a beam of 115^2 feet, and an assigned navigational draft of 46 feet. The vessel is pro- pelled by five Nordberg Diesel-driven main gen- erators and six propulsion motors capable of delivering a combined total of 12,000 horsepower to the ship's two shafts. The deep-ocean mining ship is capable of operating at very slow speeds or at speeds up to 12 knots.

Features of the Hughes Glomar Explorer in- clude automation permitting control of engine speed, direction and position from either of the ship's two complete bridges, as well as a center well and a derrick to handle the pipe from which the mining equipment will be suspended.

The vessel also has a sophisticated navigation system permitting exact location of the ship at all times and a dynamic positioning system built by Honeywell that will allow the vessel to move slowly and precisely during mining operations.

The vessel is equipped with modern messing, berthing and operating space, with a capacity to accommodate up to approximately 125 crew mem- bers and technicians required during the testing phase.

The shipyard used its 800-ton lifting capacity derrick barge, the Sun 800. in a series of heavy lifts that resulted in the positioning of heavy equipment and numerous structures on the ves- sel's topside. These included lifts of the afterdeck house, the vessel's own derrick sub base, the lift cage structure, the gitnbal, the A-frame structure, the mining equipment docking legs and the tripod masts. The most notable lift, in terms of weight, was the 750-ton lift, a record lift by Sun Ship personnel.

The keel for the Hughes Glomar Explorer was laid on December 9, 1971, and the vessel was launched on November 4, 1972. Following its departure from the Sun shipyard and completion of sea trials, the Hughes Glomar Explorer will transit to the West Coast, where it will be out- fitted with mining equipment fabricated by Lock- heed. The ship will then engage in a program of experimental deep-ocean mining and testing of various mining systems and equipment in the

Pacific.

SNAME T&R Report On

Longitudinal Stiffness Of Main

Thrust-Bearing Foundations

Vibrations on a ship are a matter of concern to ship operators, as well as ship and machinery de- signers and manufacturers, because of the nega- tive effects severe vibration may have on the operation of a ship, as well as personnel comfort.

The difficulty in estimating the longitudinal vibra- tion characteristics of a ship is the need to accu- rately calculate or estimate the required masses and stiffnesses to establish a useful spring-mass system. The Society of Naval Architects and Ma- rine Engineers Technical and Research Program, through Panel M-20 (Machinery Vibrations) of the ship's machinery committee, presents a method to determine one of the most difficult stiffnesses in Report R-15 "Longitudinal Stiffness of Main

Thrust-Bearing Foundations."

The stiffness of the thrust-bearing foundation is perhaps one of the more difficult quantities to calculate due to the wide variation in foundation arrangements and the continuity of the thrust- bearing and machinery foundation with the ships' innerbottom. Although there are several different types of mounting arrangements for the thrust- bearing, the basic procedure presented in Report

R-15 may be used to analyze any foundation stiff- ness.

The procedure involves calculating the rotation- al deflection of the innerbottom, and the bending and shear deflection of the foundation, based on an axial unit load. These deflections are then com- bined to calculate the overall stiffness of the foundation.

The report not only presents a method, with discussion for calculation of thrust-bearing foundation stiffness, but gives an example cal- culation of the method. An annotated bibliography on foundation stiffness consisting of some 25 ref- erences is included.

T&R Report R-15, "Longitudinal Stiffness of

Main Thrust-Bearing Foundations," was reviewed and approved for publication by the ship ma- chinery committee and is available through The

Society of Naval Architects and Marine Engi- neers, 74 Trinity Place, New York, N.Y. 10006, at $6 per copy. Members of the Society may ob- tain the report at a price of $4 per copy. If pay- ment is included with the order, the price includes postage via third class mail in the United States, and as "Printed Matter" in all other countries.

Shipments will be insured or sent air mail at addi- tional cost only if requested.

ABS Publishes Guide For

Inert Gas Installations On

Vessels Carrying Oil In Bulk

In view of the worldwide interest in inert gas installations and the requests received for informa- tion regarding the position of the American Bu- reau of Shipping on this matter, a booklet has been published entitled "Guide for Inert Gas In- stallations on Vessels Carrying Oil in Bulk." This guide is based on the recommendations of the

International Association of Classification Soci- eties (IACS) and the Inter-Governmental Mari- time Consultative Organization (IMCO).

Although the "Rules for Building and Classing

Steel Vessels" has no specific requirements for inert gas systems, it is stated therein (Section 36) that when an owner elects to install such a system it is to be an approved type. Inert gas installations which are fitted in accordance with this guide are considered to be an approved type. A certificate will be issued by the bureau, where the design and installation of these systems is in accordance with" this guide, when requested by the owners or builders, and a notation will be made in the record.

The "Guide for Inert Gas Installations on Ves- sels Carrying Oil in Bulk" sells for 50 cents and may be ordered from any office of the bureau or from the Book Order Department, American Bu- reau of Shipping, 45 Broad Street, New York,

N.Y. 10004.

ANOTHER VIKING FROM DRAVO: The 4,200-horse- power Wisconsin is the fourth of Dravo Corporation's new

Viking line of towboats to hit the water. It was recently launched from Dravo's marine ways at Neville Island, near

Pittsburgh. Wisconsin Barge Line, Cassville, Wis., will operate the vessel on the Mississippi River System. 10 Maritime Reporter/Engineering News