13 Nov 2017
Ship repairs: What goes on during underwater cutting and welding?
Economic significance of underwater ship repairs
In the normal course of operation, a ship is taken to dry dock once in 12 or 24 months. After thorough inspection, appropriate repair and maintenance work is initiated.
But what if a ship develops a snag below the waterline during routine service? Emergency dry docking is not feasible by any reckoning; it is economically untenable to pull the vessel out of water abruptly. The costs are prohibitive, schedules go haywire and the shipping company’s reputation could be tarnished.
Underwater repairs and maintenance is the pragmatic solution for this dilemma. It is both cost-effective and time-saving to initiate underwater repair to a ship.
A closer look at underwater cutting
Underwater cutting turns out to be the process of choice in the case of deformed propeller blades, plates or sections of plates that need to be replaced, among other tasks. It is also recommended in the case of ship wrecks, where the vessel is to be taken apart and sent to the scrap yard.
The use of a thermic lance results in fast, efficient and cost-effective underwater cutting; it is the most commonly used method for underwater cutting.
Understanding the intricacies of underwater welding
Underwater welding is useful in several types of situations, which include repairing cracks below the waterline, repairs and maintenance to the damaged/deformed areas of the hull plate and retro-fitting of hull-mounted systems.
Underwater welding can be performed in two ways – wet welding & dry welding. In wet welding, the diver performs welding directly in the water using a specially designed welding electrode.
Wet welding enables direct access to the submerged weld spot with relative ease; it is cheaper and faster as well.
In dry welding, also known as hyperbaric welding, a transient dry environment is created around the structure to be welded by attaching a dry box or cofferdam. Perhaps the biggest advantage of this process is the ability to carry out surface monitoring and check the integrity of the welds.
KBA Marine (KBAM) – proven professionals for entrusting underwater cutting & welding operations
Underwater cutting and welding are specialised activities that call for a high level of technical competency, training and practice. At KBA Marine, we have both the team, equipment and the technology for ensuring timely work underlined by lasting results.
KBAM divers have extensive experience in wet welding for temporary repairs and construction of all vessel types including bulk carriers and all other commercial ships. Our certified commercial divers are experienced qualified underwater welders, who are capable to perform the task as per the highest global standards.