Laying Concrete Mattresses...

The majority of the work we are doing these days are Concrete Mattress Lays for pipe crossings. These matts range from 11 - 17 Tons and are used to protect existing pipes from chaffing from new pipes being laid over top. These particular matts are the biggest I have ever seen, 17 Tons, 20 feet long x 10 feet wide and about 1 foot thick. They are held together by heavy poly-rope.

We use the cable loop seen here and the manipulator (robotic "arm") to guild them into place while they swing on the end of the crane wire from approximately 600 meters up on the surface. It's quite tricky, all things considered, especially when one false moove can stir up the silty bottom and hamper visibility for up to a half hour at a time.

This is what a good matt placement looks like, almost seamless, it appears perfectly lined up, without a space between the two. The project tolerance on this particular job is 11 inches, however within the ROV group we rarely stand for mor than 6 inches off...mostly out of pride...hahaha!