Hydrex Darkest Africa Bow Thruster Repair

Press Release
Tuesday, February 12, 2013

A Hydrex diver/technician team flew to Pointe-Noire, Congo to replace the stainless steel belt in a research ship's thruster tunnels.

The stainless steel belt is installed around the perimeter of a thruster tunnel at the location of the thruster blades. There the impact of the cavitation caused by the movement of the blades is the most severe. Extra protection against cavitation damage is therefore essential. When the stainless steel belt in the thruster tunnel of the research vessel suffered cracks, the underlying steel was exposed to cavitation. The belt needed to be replaced as soon as possible to prevent the thruster tunnel from getting damaged too severely. The owner of the vessel would have had to take his vessel to drydock if no on-site solution was found.

A tailor-made open-top cofferdam was designed by the Hydrex technical department. It was constructed in a local workshop in Pointe-Noire under the supervision of Hydrex diver/technicians. At the same time a regular shaped second cofferdam was also built. Cofferdams like these are used to close off the thruster tunnel on both sides. Water can then be drained from the tunnel, creating a dry working place. This allows the team members to descend into the tunnel through the open top. They can then carry out any necessary welding work in drydock-like conditions.
 
This prevented an unscheduled drydock visit for the ship and saved the owner precious time and money.

Unfortunately underwater visibility was down to near zero, so the ship was moved to an anchorage at Port Gentil, in neighbouring Gabon, where conditions were more favourable. Here a diving station was set up and the diver/technicians started the installation of the cofferdams. Next they emptied all water from the thruster tunnel. They then descended into the tunnel and carried out the repair. The old, damaged, belt was removed and replaced with a new stainless steel belt.
 
The actual operation was finished in only five days. The team removed the cofferdams and the ship was ready to continue its schedule with its thruster tunnel fully protected against cavitation once more.


 
 

Maritime Reporter November 2014 Digital Edition
FREE Maritime Reporter Subscription
Latest Maritime News    rss feeds

Contracts

Port of Galveston to Repair Public Pier

Galveston Wharves’ board of trustees today unanimously approved a project to repair pilings and pier deck in the Pier 19 area of the port. The board awarded the contract,

NASSCO Cuts Steel on APT "ECO Tanker"

General Dynamics NASSCO started construction of another ship in its commercial shipbuilding backlog, starting construction of a second “ECO” tanker to be built

Multraship Buys Three More Tugboats from Damen

Multraship and Damen Shipyards Group agreed on three new ASD (Azimuth Stern Drive) Tugs, all for delivery to Multraship in 2015. After delivery in Vietnam, scheduled

Ship Repair & Conversion

NMEA Updates Installation Standards

2014 edition of NMEA 0400, Version 4.00 features extensive updates and new information   The National Marine Electronics Association (NMEA) has published Edition 2014, Version 4.

Hoists Facilitate Offshore Crane Repairs

When the diesel engine of a deck crane failed, it caused major handling problems for an offshore platform operating in the Dutch sector of the southern North Sea,

NASSCO Opens Bremerton Repair Facility

General Dynamics NASSCO celebrated the grand opening of its new location in Bremerton, Wash., yesterday. The facility will support the company’s recently-awarded contract to repair and maintain U.

Underwater Engineering

Mermaid Wins Subsea Contract in Gulf of Thailand

Mermaid has secured a 2-year contract for its dive support vessel, ‘Mermaid Commander’, to provide subsea construction support in the Gulf of Thailand for a

Vard Wins Farstad's OSCV Contract

Vard Holdings Limited (“VARD”) has secured a contract for the design and construction of one Offshore Subsea Construction Vessel (“OSCV”) for Farstad Shipping (“Farstad”).

Sonardyne’s Ranger 2 Chosen for Pieter Schelte

Sonardyne’s Ranger 2 Ultra-Short Baseline (USBL) acoustic positioning system has been selected by the Swiss-based Allseas Group for the world’s largest pipelay

 
 
Maritime Careers / Shipboard Positions Maritime Security Offshore Oil Pipelines Port Authority Salvage Ship Repair Ship Simulators Sonar Winch
rss | archive | history | articles | privacy | terms and conditions | contributors | top maritime news | about us | copyright | maritime magazines
maritime security news | shipbuilding news | maritime industry | shipping news | maritime reporting | workboats news | ship design | maritime business

Time taken: 0.1652 sec (6 req/sec)