Hydrex reports that diver/technicians performed underwater thruster operations on two vessels simultaneously in Coatzacoalcos, Mexico. Repairs were carried out on both azimuth thrusters of an FPSO while the thruster seals of a heavy load carrier were replaced.

Both vessels are managed by the same company. They were suffering from leakage problems on their propulsion system. We received these inquiries and were able to combine both repairs in one operation. This gave our costumer the advantage of only one mobilization for both vessels and kept the cost within budget.

The stern thruster tunnel of the heavy load carrier was sealed off with our flexible mobdocks. All water was then emptied from the tunnel, creating a dry workspace around the thruster unit. A full inspection of the unit revealed that all blade and shaft seals were leaking. Our diver/technicians first replaced the four blade seals. The three shaft seals were then replaced in cooperation with the representative of the OEM.

The other vessel was an FPSO which had suffered a problem in the oil distribution box of one azimuth thruster. A special cofferdam was designed by the Hydrex R&D department to create a dry environment around this part of the thruster. This enabled our team to perform a complete repair without removing the thruster. The other azimuth thruster had more serious problems and a complete removal was required. As the thruster was not designed to be removed underwater, we created a custom procedure for this.