Page 37: of Maritime Reporter Magazine (September 1981)

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and weight savers, with overall compactness, minimum tail swing and comparative lightweight.

Space and weight are two very important factors in offshore op- erations where every square foot and pound can directly affect capital investment and operating costs.

For heavy-duty operations of rugged environments, National

Supply offers four North Sea- proven models with standard boom lengths to 140 feet and maximum load capacity to 180,- 000 pounds. Crane models include the OS-105, OS-215, OS-435, and the new OS-435 Heavy-Duty. components are modularized for fast inspection and easy replace- ment or servicing when neces- sary. Major components are weather protected.

On large National models, pneu- matically actuated controls pro- vide better dependability and less maintenance.

Both main and fast line hoists have two-stage planetary reduc- tion systems that are completely enclosed. Gears and bearings are lubricated during drum rotation.

Power controlled load lowering is standard.

The boom hoist has a two-stage planetary reduction system with- in the drum, automatically oper- ated lock pawl and power-con- trolled load lowering.

Swing is powered by a reversi- ble motor-drive through a multi- stage gear reduction system with anti-friction bearings and oil- tight case. Gears and bearings have force feed lubrication. The swing brake is mounted on the gear reducer input shaft.

For free brochures on National

Supply cranes and offshore equip- ment,

Write 43 on Reader Service Card (continued on page 40)

For lighter duty offshore oper- ations, National now offers a com- pletely new line of small cranes.

The OS-45, OS-35 and OS-25 give boom lengths to 100 feet and maximum load capacities to 68,- 000 pounds. These models are de- signed specially for the light-to- medium lifting requirements of many production platforms, small jackups or service rigs.

Heavy, or light-duty National cranes are versatile and adapt- able to most dockside or other marine functions.

National offers a unique hy- draulic power system. For the variety of offshore lifting re- quirements, separate motors are incorporated for the boom hoist, main hoist, fast line hoist and swing systems, adding to overall crane reliability and perform- ance.

Unlike most systems, maximum system pressure is not constantly maintained; rather, pressure var- ies to satisfy load requirements.

The result is better lift efficiency, longer service life.

A console, designed for easy operations, allows each crane function and its speed to be easily controlled by the operator. Sep- arate hydrostatic circuits mean functions are completely inde- pendent of each other and can be individually or simultaneously controlled with no loss of speed, power or lift.

National cranes are designed for safety with forged alloy steel swing bearing and matching adapter flange. Ball races are hardened and ground with gear teeth designed as an integral part of the outer race.

The entire hydraulic system plus major power and control




LOADMAX is the quick, easy way to plan optimum load- ing for any type of ship. It rapidly calculates and displays accurate draft, hull strength and stability data for any load- ing condition.

LOADMAX is as simple to use as a desk calculator— tonnage distribution and calculated results are read at a glance —no confusing knobs, thumbwheels or cluttered

CRT displays typical of other loading instruments.

Designed for the particular operating requirements of your ship, LOADMAX combines numeric tonnage displays with an easily understood mimic diagram of the vessel. A separate graphic display shows whether the ship is in hogging or sagging condition and if shear force or bending moment limits are being exceeded. Write for a FREE brochure with detailed information today. Raytheon Ocean Systems

Company, Westminster Park, Risho Avenue, East Providence,

RI02914 U.S.A. (401) 438-1780

Summary displays

Shear force and bending moment graphic display

Ship mimic diagram and mimic tonnage displays

Draft aft display

Power "on-off key switch

Shear force and bending moment point "fine" display select buttons


Optional tank capacity table

Carrying handle

Operating mode control switches • lightship • self-test • port condition • run

Shear force and bending moment numeric "fine" displays Shear force and bending moment graphic display select switch

Draft forward display

Entry keyboard display

Simple 19-key

Entry keyboard

Cover latch

Special function keys

Computer printout (optional)

September 1, 1981 Write 200 on Reader Service Card 39 1

Maritime Reporter

First published in 1881 Maritime Reporter is the world's largest audited circulation publication serving the global maritime industry.