SubSea Solutions Alliance Demonstrates Their Versatility
A tale of a Tough Repair...
Prior to transiting the Panama Canal, grounding caused considerable damage requiring immediate repair to the bow section of a vessel. Due to the location and significance of the damage a unique repair solution that could be completed efficiently and in a safe manner was required. Upon completion of an inspection dive, multiple tears and openings in the hull were found from the tip of the Bulbous bow all the way through multiple frames on both the starboard and port sides of the vessel. The largest rupture was 12 meters long with an approximate width of 1 meter. Other ruptures included affected areas over 2.5 square meters in area. Both the port and starboard sides of the vessel were affected over 30 frames with significant ruptures and tears.
As the engineering department at the Subsea Solutions Alliance developed the repair procedure, consideration for where the vessel was anchored was critical as it was in a lightly sheltered outer anchorage. Weather was considered when developing the unique, safe and class approved temporary repair.
As the vessel was fully loaded, the draft and location of the damage required specialized dive equipment for deeper drafts. Work was performed by divers up to 40 feet below the water line. The divers would template the damaged hull form to determine the required framework and size of the doubler plates. While the divers continued working on other damaged areas, the required plates were prepared on the support vessel and then lowered to the divers to be installed. The repair of the damage required underwater as well as topside welding / preparation work. The member companies of the Subsea Solutions Alliance already have class “A” wet weld procedures according to AWS D3.6 – Specification for Underwater Welding , approved by the major class societies. With a considerable work force of diver / technicians certified to these procedures the team could be immediately dispatched from Long Beach, California, Miami Florida, Vancouver and Panama to the vessel’s location.
Since the damage to the vessel was located near the fore peak tank and the vessel was in a lightly sheltered outer anchorage the repair could not utilize the conventional approach with cofferdams as the potential risk of the anchor chain “ripping off” the cofferdam in the heavy seas was present.
After the completion of a detailed inspection and a meeting with the attending class surveyors and underwriters, the engineering department of the Subsea Solutions Alliance developed a repair procedure that was subsequently accepted by all certifying bodies and performed without delay. This procedure included 3-D modeling as well as a full stress analysis to ensure that the intended repair procedure would be robust enough to withstand the impacts the vessel would endure on its transit to its intended destination.
Underwater welding was performed in the manner as described in the approved Class “A” wet weld procedures. Frame and stiffener members matching to the original hull quality were welded underwater in the shell plate openings. Doubler plates matching the original hull steel quality and thickness were then welded into place underwater. Once all underwater welding was completed a two part underwater epoxy was installed over all weldments to assist in the protection and reduction of metal wastage in those areas immersed in salt water. Once the affected areas were closed off with the doubler plates, the affected areas were dewatered, dried and cleaned.
Watertight bulkheads between the tanks where damage occurred were dried, cropped away and subsequently replaced. The repair was done in accordance with class requirements to ensure the structural integrity of the affected area.
Braving the weather, heavy sea conditions and significant depths required to perform the repairs to this fully loaded vessel, the diver / technicians of the Subsea Solutions Alliance completed these repairs in a 2.5 week period. Yet again the member companies of the Subsea Solutions Alliance met the challenge of a unique repair process. Another satisfied customer sailed away to offload its cargo at its intended point. By maintaining a permanent work force of over 150 diver / technicians around the world, the member companies of the Subsea Solutions Alliance are available and ready to tackle your vessel’s toughest needs. With equipment designed for quick mobilization strategically located throughout the world, we remain ready to meet your emergency or maintenance needs. Click on the image to see them featured on the National Geographic Channel.