Page 44: of Maritime Reporter Magazine (April 15, 1973)

Devcon Plastic Shims For Crane Rails

Provide Accurate Alignment At Low Cost

An overall view of some of the PACECO MACH Portainers at Port Newark. Devcon plastic shimming was used on these cranes to reduce construction cost and time.

Port Newark, N.J., contains what is probably t'be largest- container facility along the Eastern Sea- board. The key to its efficient op- eration is 'the giant crane used to load and unload the containerships —there are nine such cranes.

Each PA'CECO crane has a boom 296 feet 'long which travels horizon- tally. The lower structural mem- bers of the boom consist of two 296-foot-long I-beams with 200 feet of upside-down railroad-type rails bolted to each one. Because of the long boom length, heavy loads in- volved and close travel tolerances, construction of the boom is critical —it must travel back and forth without binding.

The mating surfaces of each I- beam and each rail section must be exactly level to assure an exact and smooth horizontal boom move- ment. However, beams and rails of the lengths involved will never be exactly level throughout. Mating the rail to the I-beam without eliminating these differences could cause uneven horizontal travel and binding of the boom due to the close travel tolerances. Normally, metal shims would be used to pro- vide the leveling function or one single shim made to conform to the varying elevations could be used.

Either way, because of the lengths and microscopic differences in mea- surement, a difficult and critical machining and welding operation would be necessary.

This analysis caused the engi- neers to seek an alternative solu- tion for shimming between the I- beam and rail. They selected Dev- con WR and WR-2 because of their wear resistance, hardness and ease of use. Using WR, the engineers were able to fabricate one con- tinuous shim that conformed to all elevation 'differences between the mating surfaces, yet did not re- quire machining. In addition, the

WR performed a secondary func- tion ; it provided a built-in cushion, permitting the rails to adjust more easily to varying stresses exerted on them by rotational forces caused by the horizontal movement of the boom when under load.

The WR was applied in the final phase of the boom construction.

With the boom structure elevated a short way above the ground, the rail is positioned on jacks under the particular section of the I-beam to which it will finally be bolted.

The lower plate of the I-beam is sandblasted, wiped clean with sol- vent and thoroughly dried. Liquid

WR is immediately brush-coated on the sandblasted section. The up- per plate of the rail is also sand- blasted, solvent cleaned, dried and a release agent—a Dupont paste wax for automobiles—spread over the surface. Temporary spacers J4 inch high and vertical guides are tacked to the I-beam to correctly position the rail.

As soon as the I-beam and rail have received their respective ini- tial coatings of WR and release agent, Devcon WR-2 with the ap- propriate portion of slow hardener is mixed using a Devcon M-60 mix- er. When thoroughly mixed, the material is puttied onto the rail over the release agent to the ap- propriate thickness. The rail sec- tion is then jacked up against the

I-beam, fastened, and the excess

WR-2 that was forced out along the edges wiped off.

Since the WR-2 had to be com- pletely cured to be effective, the

Shore-D hardness value had to be tested. On the initial application this was done by fastening the rail to the I-beam with special clips.

When the WR-2 was cured, the rail was undipped, dropped down and the Shore-D hardness checked along the rail. (All the WR-2 ad- hered to the I-beam, none was found to adhere to the rail sur- face.)

Subsequent applications, nine crane booms, consumed over two tons of WR and WR-2, obtained through Pedley-Knowles & Co. of

San Francisco, Calif., a distributor for the Devcon Corporation, Endi- cott Street, Danvers, Mass. 01923.

Title XI For Four

Tug/Supply Vessels

Approved In Principle

An application filed by Aquamarine

Associates, Houston, Texas, for Title

XI mortgage and loan insurance in connection with four tug/supply ves- sels has been approved in principle by the Maritime Administration.

Burton Shipyard, Inc., Port Ar- thur, Texas, will build the vessels at a total cost of $6.5 million.

Ferguson To Build First

Highly Skewed Propeller

For U.S. Merchant Vessel

The award of an $869,000 con- tract to install the first highly skewed propeller on a U.S. mer- chant vessel was announced by

Robert J. Blackwell, Assistant Sec- retary of Commerce for Maritime

Affairs.

Awarded to Aries Marine Ship- ping Company, the contract covers the manufacture, testing and evalu- ation of the propeller.

To be 'built by Ferguson Propel- ler Reconditioning Ltd., the pro- peller will be installed on one of the two "San Clemente" Class ore/ bulk/oil (OBO) vessels now being built for the company by National

Steel and Shipbuilding Company,

San Diego, Calif.

Since both OBOs are the same design, installation of a regular propeller on one vessel and the skewed one on the other will pro- vide performance data on the two types of propellers which can be accurately compared.

Shaped like a pinwheel, the skewed propeller is expected to aid in reducing the damage to ships caused by vibrations resulting from the interaction between the propel- ler and the water flow in which it turns. Reduction of vibration will increase the habitability of work areas and crew quarters aboard merchant vessels, as well as length- ening the life of shipboard equip- ment.

Sound Powered Telephones

For simple, trouble-free, point-to- point, instant voice communications anywhere on shipboard. Nothing beats Henschel for reliability.

Shaft Speed Indicators

Traditional pointer-type indication is sti preferred by many. The newer solid-state integrated circuit systems can provide digital readout at any number of on-board loca- tions.

Engine Order

Telegraphs

These systems have become a familiar symbol of precise ship control. Pedestal mounted or built into a console, current models are even more convenient to use.

Throttle Control

Direct Control of Engines from the Bridge is now practical for even the largest of vessels.

Shipboard Signaling and Intercorr

Please Write or Telephone for More Information and Data Sheets 46 Maritime Reporter/Engineering News