Launching a Mat

It was early Saturday morning and the heavy clouds only added to the cold weather. An occasional small drop of rain would hit the windshield of my brother’s 1971 Corolla as we headed down the highway to watch the launching of a mat.  Heavy gray clouds hung from horizon to horizon and the forecast was of lessening rain and continued clouds through the day.

I was working offshore at the time and my oldest brother was a welder in a shipyard. I was off for the week and he was off for the weekend. Neither of us had much sleep the night before, since he was working the three to eleven shift and we usually would go get a beer after he was off work. It didn’t matter; we were on a mission. They were launching a mat this morning and we wanted to watch.

What’s a mat? It’s part of a mobile offshore drilling platform, which comes in three basic styles: submersible, semi-submersible and jack-up, which is what this mat would be attached to when the platform was finished.

A submersible platform sits on the sea bed. It’s limited by water depth, since there’s no adjustment to the position of the platform. After a certain depth, the other two are required.

A jack-up rig has adjustable legs. The legs are used to adjust the height of the platform to compensate for different water depths. After a few hundred feet, this platform can’t be used, so the semi-submersible is used.

A semisubmersible platform floats, but to prevent too much movement of the platform in rough seas, two large barges, which are attached to legs, float beneath surface and use the stable water under the surface to stabilize the platform. Water is pumped either in, or out of the barges to adjust the height. When the rig is moved, most of the water is pumped out and the rig is towed by huge sea tugs. At that time, the barges are exposed and the deck over one hundred feet off the water. While on location, huge anchors, or horizontal propulsion stabilizers hold the position over the well location and the drill string hangs beneath the derrick.

The mat to be launched was part of a jack-up rig under construction. Eventually, it would be on the bottom of the legs. This hull would be sunk to the bottom to support the legs, or raised to help stabilize the platform when moved.

This mat was unique, since it was a widow-maker. During construction, one person was killed and another terribly maimed when the skids fell over. I remember my brother telling me about the incident. Noticing the skids were leaning before his shift, he refused to go under the mat. His shift ended without incident. The night shift wasn’t so lucky. It was during that shift when the accident occurred. Evntually, the mat was lifted and the skids repositioned.

We were too early. Since there was no tug on site, we decided to kill some time and just drove around for about an hour. When we returned, there was a harbor tug waiting in the slip to catch the mat after it was launched.  We pulled over to the side of the road and waited.

Our vantage point wasn’t the best. We could see most of the top part of the mat, but we couldn’t see the skids. Still it was better than not seeing anything, although we both would have liked to be in the shipyard and close to the launching location.

We waited almost an hour before we saw the mat start moving down the skids. Since we couldn’t see the bottom of the mat, we were both surprised by the huge wave that soon appeared in front of the harbor tug. The captain gunned the engines and rode over the ten foot wave that continued down the slip; washing debris and the shallow vegetation away as it passed.  Sufficiently awed by the event, we spent a few minutes just watching as the tug maneuvered into position and eventually secured the mat. It would be pushed to a dock so the rest of the superstructure could be attached. These components were either complete, or in the process of being completed. A 600 ton floating crane, which would attach many of these huge sections, was docked in the distance. The huge boom towered over the shipyard.

With nothing left to see, we headed home. We had no idea that these enormous endeavors would eventually end and the shipyard would close.  The collapse of the oil exploration industry was coming and these thousands of workers would join the hundreds of thousands without work. An era was ending and we had witnessed what subsequent generations would never see.