The LASER PTM has been the first underwater pipeline post-trenching machine that SEA has designed and assembled in order to operate in hard seabed, with sedimentary rocks such as calcarenite, sandstone and limestone.
![](http://www.seatrenching.it/wp-content/uploads/2015/12/3.2-Laser.jpg)
By improving the Laser PTM design, SEA has designed and assembled the RACK PTM, an underwater pipeline post-trenching machine, that is more resistant and with higher trenching performance in rock.
By employing this PTM, SEA has successfully carried out projects in rocky areas where the post-trenching method had not been considered feasible before.