Subsea Solutions Alliance: "Weld Seams Aren't Sealing!"

Published Aug 29, 2011 9:10 AM by The Maritime Executive

While performing a condition survey on a vessel in the Caribbean, it was found that some weld seams had eroded away and the bottom plating of the rudder blade was dramatically corroded. The rudder blade bottom plating showed deep corrosion in the way of the starboard leading weld seam. The weld seam was eroded 100% all the way through across its entire length of approximately 1.5 meters. This left the weld seam between the rudder and bottom plate completely exposed. As this survey was being performed under the watchful eyes of the classification societies surveyor, a repair was required. Based on the findings, the client sought a PERMANENT repair solution based on the
findings. Considering the location of the damage and the requirements of the specific classification society, in order to execute a permanent repair, welding on the rudder blade would need to be performed in a dry environment. Wet welding could only be used to tack weld the new bottom plate into place and to install rigging aids for the subsequent cofferdam that was designed. The engineering department of the Subsea Solutions Alliance was called into action.

Preparatory work to the affected area of the rudder began with removing the affected weld seam on the bottom plate by hydro-gouging. An internal inspection of the rudder was performed to assure the client and the attending surveyor that no further corrosion or damage occurred. No additional damage was found on the internal framing. While preparatory work was taking place, the rudder was fully templated so that an engineered hyperbaric cofferdam could be fabricated.

Once constructed and the preparatory work was completed, the hyperbaric cofferdam was installed into position and de-watered to create a dry environment. Class certified steel was procured and a new bottom plate for the rudder was fabricated on site. Welding then commenced in accordance with the class PRE-APPROVED repair procedure developed and submitted by the engineering department of the Subsea Solutions Alliance. Welding and heat treatment of the weld seam was performed in accordance with the pre-approved procedure; witnessed and certified by the attending classification society surveyor and the client. Once all of the welding was completed and the welds and the heat affected zones cooled down to ambient temperature, the required non-destructive testing was performed in accordance with the pre-approved procedure. The affected area was coated with corrosion protection and the job was completed.

From simple video surveys to complex in water repairs, the Subsea Solutions Alliance can provide the entire portfolio. Utilizing the same team that performed the survey provided financial value as well as continuity through the performance of this repair. Multi-skilled diver / technicians, certified in all facets of underwater ship repair, supported by an in-house engineering department enables the Subsea Solutions Alliance to deliver the entire repair; all in house! Let us know what we can do for you.

The Subsea Solutions Alliance (SSA) consists of the underwater ship repair specialists: All-Sea Enterprises Ltd, Miami Diver LLC, Parker Diving Service LLC and Trident BV. For additional information, please feel free to visit the web site of the Subsea Solutions Alliance at www.subseasolutions.com or contact Mr. Rick Shilling, Business Development and sales.