In water seal repair: requirements & preparations

Sabrina Peters

In water seal repair, it sounds interesting but how does it work and what preparations need to be made? Earlier we already had a blog about “In Water Survey instead of drydocking” and now we want to breakdown the in water seal repair part of the job. To get things moving, a number of actions are required and begin to move into place.


The first step is to get in touch with Lagersmit for specifications on the seal system. Drawings are required in order determine a number of factors ranging from what size habitat will be used, to what size seal system is in place in order to begin assembling the proper tools and spare parts for the repair. Subsea Global Solutions (SGS) will coordinate with Lagersmit throughout the entire project in order to maintain quality and consistency. Other arrangements need to take place, such as where the vessel will berth and what the timeframe and diving conditions look like. SGS can mobilize anywhere in the world in 48hrs to attend a vessel in need.


  1. Coordination with the vessel for location and timeline
  2. Mobilization of SGS Diver technicians, two teams to work around the clock
  3. Dive inspection and pressure testing for pre diagnosis of the seal malfunction
  4. Templating and fit up/ installation of the underwater habitat
  5. Coordination with Lagersmit regarding spare parts and field service engineer


The initial dive will consist of an inspection to assess the extent of the repair. If the condition of the rope guard and seal rings are intact, it may be as simple as replacing the worn seals with the new Lagersmit seal. Other scenarios encountered over the years have included missing pieces of the seal box, machined housing parts whether by a detached rope guard or debris encounter underway, corroded seal assembly parts etc.


Photo: Rope guard removed for an in water seal inspection. Cruise Vessel, Port Everglades FL
After the initial inspection, the diver technicians will begin installing the habitat around the stern tube and propeller hub. While this is in motion, on board the vessel there are a few necessary preparations taking place. Header tanks and valves need to be isolated; the vessel may need trimming for oil containment purposes, the stern tube will need draining and so on. View the process in pictures below! As pictured from several different projects.


Photo: SGS Diver/technician Jonathan and Lagersmit Service engineer Maurice performing forward seal change out. Ferry Vessel, BC, Canada
Photo: SGS Technician Dale Ellenson inside the habitat working on the seal system Cruise Vessel, Nassau, Bahamas


The advantages of performing an in water seal change out as opposed to dry dock are numerous, however, the biggest advantage aside from being more cost effective, is time. Depending on the vessel, an in water seal repair will be performed without interruption to the vessels itinerary. A Cruise ship will remain in service with passengers aboard while SGS is performing an in water seal repair.

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