Port Rudder Ram In-Water Replacement

Shearwater Marine Services (Shearwater) successfully completed an in-water repair of the Port Rudder Ram on a naval vessel, a first-of-its-kind accomplishment. The initial plan to use a Rudder Cofferdam for dry access was not feasible, leading to the development of a collaborative and innovative solution involving multiple diving teams and stakeholders. The repair was completed in a challenging environment, with meticulous planning and execution, ultimately finishing only two days over the scheduled timeline.


In February 2020, an issue with the hydraulic system of a naval vessel's rudder was discovered, resulting in sea water contamination. The initial plan was to investigate this defect using a Rudder Cofferdam, however this could not be fitted successfully. Shearwater developed an alternative solution that involved diver entry into the Aft Free Flood Space (AFFS), a .


The challenge was to carry out the in-water repair of the Port Rudder Ram, given that the Rudder Cofferdam could not be fitted. The repair involved a series of complex tasks that had never been conducted in-water before, requiring innovative solutions, meticulous planning, and collaboration across various stakeholders.


SMS and its partners developed a first-of-its-kind in-water repair solution, which included the following key steps:

1. Investigation and repair timeline: From December 2020 to July 2021, Shearwater carried out various activities, including ROV and diver entry, hydraulic leak detection and repair, in-water repair of the Port Rudder Ram, sourcing a replacement Rudder Ram, and successful pressure testing after the repair.

2. Repair methodology: The repair process involved removing the defective Ram, workshop activities to prepare the new Ram, and fitting the replacement Ram.

3. Collaboration: The success of the repair was possible due to the involvement of various stakeholders, including Shearwater, BAE Systems, Babcock Whetstone, PSM/PSO, Clyde Diving, Design Authority, Fleet Programmes, Fleet Engineering, Fleet Compliance, Fgen/Navyops, and Clyde Lift Plans.


Shearwater successfully completed the in-water repair of the Port Rudder Ram, overcoming numerous challenges, such as:

• Ram internal slinging within the AFFS

• Slinging of Rudder Ram in/out of the AFFS

• Tiller Pin Nut removal

• Pilgrim Nuts removal

• Hydraulic Swagelok connections

• Fitting of Bearing Top Hats to the new Ram

• Strength Testing of eye bolts and cleats within the AFFS


Shearwater Marine Services demonstrated exceptional expertise, dedication, and innovation in completing this first-ever in-water repair of the Port Rudder Ram. By working closely with multiple stakeholders and diving teams, and overcoming numerous challenges, Shearwater delivered a successful repair that was only two days over the scheduled timeline. This case study showcases the capabilities of Shearwater in providing innovative and effective solutions in challenging environments.

Find out how Shearwater
Can Support You