Page 41: of Maritime Reporter Magazine (August 1997)

R/EN Review: Deck Machinery & Cargo Handling Equipment

Company Profile:

Marine Travelift

Study Finds Vessel

Slings Benefit Hull

Stress levels

A recent study commissioned by

Marine Travelift and conducted by

Bay Engineering, entitled Hull

Bending In Vessels Supported By

Slings, shows that vessels support- ed by slings on the 300, 500 and 800 BFM models of Marine

Travelift mobile boat hoists are not overstressed. The maximum stresses occurring in the vessels are well below allowable stress lev- els. "Marine Travelift is moving for- ward ," explained A1 Lamer, exec- utive vice president of Marine

Travelift. "And as our new models of lifts shatter past capacity records, we decided it was time to provide the industry with mathe- matical proof that these increased capacities were justified."

Bay Engineering is an architec- tural firm specializing in the design of large commercial self- unloading cargo vessels.

A literature search gave the engi- neers the range of data needed to develop average and extreme ves- sel characteristics for each one of the three subject boat hoist mod- els. A total of 160 different vessels were used, in sizes up to 200 ft. in length, and in displacements up to 1,300 tons.

The displacement, depth, width and draft were all plotted versus length, and a regression analysis was performed to obtain a power equation for each of these charac- teristics as a function of length.

Displacement was considered to be the "light ship weight" plus a small variable load. Also, a second sub- set of the data consisting of all ves- sels with high length to weight ratios was generated. This subset allowed the test to account for the special features of longer vessels.

When available, steel weight, machinery weight and outfitting weight were plotted as a ratio of total weight versus the volume parameter (LBD/100), also known as a vessel's cubic number. A regression analysis was performed on each of these graphs in order to get component weights for a typi- cal weight distribution curve for the vessels.

The midship hull girder section modulus was determined using minimums required by the

American Bureau of Shipping (ABS) for average boat character- istics. The midship moment of inertia was also determined using a minimum ABS formula. A typi- cal vessel shape was then assumed in order to calculate the moment of inertia and section modulus distri- bution curves for each vessel.

Analyses were performed using the typical vessel characteristics of average and long length vessels for the following conditions: A typical weight distribution was assumed for all vessels investigated. The

LoadRlte, LEVELMASTER and INSONEX are registered trademarks et

Kockum Sonica AB. Windows Is trademark registered by Microsoft Corp.

Specifications are subject to change without notice.

Norsellght A/S Kockum Sonics Inc Kockum Sonics Inc Kockum Sonlcs Kockum Sonlcs AG

Berg, Norway North Vancouver, Kenner, L.A. U.S.A. (UK) Ltd Dubendorf, Switzerland

Tel:+47 69 17 99 99 Canada Tel:+1 (504)466 9740 Leighton Buzzard, UK Tel:+41 (01) 820 31 91

Fax:+47 69 17 99 89 Tel:+1(604)924 1519 Fax:+1(504)466 9792 Tel:+44(0)1525 85 2323 Fax:+41 (01) 821 26 52

Fax: +1(604)924 2435 Fax:+44(0)1525 853505 i There is a LoadRite® cargo planning system for every type of ship including tankers, bulk carriers, general cargo vessels, RO/RO carriers,

I container ships, passenger vessels etc. The system comprises a basic j : software package, a comprehensive range of software options and the latest j§ personal computer ruggedized for marine use.

For the past 20 years Kockum Sonics have developed |j| LEVELMASTER® tank gauging systems. The latest version is called

CALM (Computer Aided Level Measurement) and the system is available with electro-pneumatic, or pressure sensors, or with a combination of both.

The electro-pneumatic sensors compensate for small pressure leakages.

Presentation either by digital display DU 350 or in KSL 450 which is a

Windows® 95/NT executed program. (((•))) Kockum Sonics

Corporate headquarters:

Kockum Sonlcs AB, Malmo, Sweden, Tel: +46(0)40 671 88 00 ,

Fax: +46(0)40 21 65 13, E-mail: [email protected]

Kockum Sonics marine product range includes the following:

Marine whistles

LEVELMASTER®

LoadRite?

Shims

INSONEX1 - signalling equipment - level gauging systems - cargo planning systems - ship management systems - sonic cleaning equipment

Searchlights/Floodlights - lighting equipment

August, 1997 Circle 348 on Reader Service Card 41