Page 5: of Maritime Reporter Magazine (April 15, 1973)

A semisubmersible drilling platform similar to the French-built Pentagone 81 pictured here is being built at Marathon's Brownsville, Texas yard for Societe de Forages en Mer "Neptune." The Pentagone 81 is a 5-column platform. The rig can drill in water depths to 600 feet, and its special design enables it to perform in rough sea environment.

Welder Training—Welders receive personal instruction at Marathon's new shipyard in Brownsville, Texas. Over 600 trainees have completed the course and have been certified to ABS standards. The yard has about 100 welders in the program on a con- tinuing basis. The trainees are paid for time both in the classroom and on the job.

Shop's automatic flame cutting machines. However, there are two other methods used by the yard for plate patterns. One other method is for the company draftsmen to reduce the full-scale drawings to l/10th scale. The l/10th pattern can be put under the reader on a special flame cutter and the cutting machine will convert to full scale.

Still another method is to take a picture of the l/10th scale draw- ing. A glass negative about three inches square is produced, and the negative is placed in an optic sys- tem. The drawing image is project- ed onto the steel plate and a work- er, using a tape roller, traces the pattern. The glass negative avoids the problem of distortion in pro- jection of the pattern.

Shears in the shop will handle plate to 12 feet in size and one inch in thickness. The largest of the plate rolls will take care of j^-inch steel up to a length of 36 feet. Press brakes are available to meet all re- quirements. The shop can form in- tricate shapes and angles.

Automatic welding machines are located in the shop and in the plate fabrication area just outside the shop. In this assembly area, two 30-

The two cranes have a clear hook height of 65 feet.

A 150-ton-capacity dolly is used to move components a short dis- tance to the forming and subas- sembly slab. The slab is about 400 feet long and about 200 feet wide —'big enough for fabrication of large vessel modular sections. The slab is actually an extension of the building ways. These ways are 200 feet wide and 1,400 feet long. Mar- athon has installed rails the full length of the building ways and the slab. The rails are for a 250- ton-capacity mobile gantry crane which is not yet installed. The crane will have two hooks and a clear span of 200 feet. Hook height will be 200 feet.

The full length of the building, outfitting and launchways are crossed by launch beams set on 19-foot centers. The beams have a load bearing capacity of 16.25 tons per linear foot.

The 250-ton gantry crane will lift the subassembly sections from the fabrication slab and move down the building ways and lower the sections onto building platens.

These sections are then joined to form the completed vessel.

The building platens are vital to

Marathon's vessel transfer system on the building and outfitting ways.

The platens ride the beams. With its hydraulic transfer system, the yard is able to move the vessels in any of four directions. The yard is set up for side launches. The system permits vessel transfer either toward or away from the launchway, or forward or backward parallel to the launch. This feature offers maximum utilization of the building/outfitting area.

On the building ways, all heavy machinery items are placed aboard, and major steel work is completed while the vessel is on the building platens and being serviced by the 250-ton gantry. After this is com- plete, the vessel is then transported to the outfitting ways outside the gantry rails. At that time, another vessel can be started on the build- ing ways.

To this point of construction, the vessel has gone together primarily in a modular construction manner.

The steel fabrication processes are either automated or semi-auto- mated. It's on the outfitting ways that vessel construction is more in the conventional method of ship- building. At this point, coating of the vessel is accomplished. Internal piping, electrical and machinery in- stallation (not already in place) may be handled during this paint- ing process. The outfitting ways are not served by overhead cranes.

For material handling jobs at this point, temporary cranes are placed aboard the vessel. These cranes are wide - based skid - type revolving cranes which are moved about as need dictates. (Continued on next page)

Components Are Huge—Shipyard workers perform tasks on a section of a semisubmersible offshore rig. Heavy duty material handling equipment enables the yard to fabri- cate large components before moving to building ways.

Grinding Operation—This worker is shown as he smooths out the steel in a tubular section of a semisubmersible mobile offshore drilling platform. Marathon currently has an employment of 1,800 in the new yard.

Automatic Welding Machines—These workers are using an automatic welding machine for work on a component section of a semisubmersible offshore drilling rig being built at Marathon's new Brownsville shipyard.

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