SubSea Solutions Latest Newsletter Now Available

By MarEx 2011-04-12 12:43:16

In this issue SSA highlights:

  • Propeller repairs and improvements
  • Permanent In-water Weld Repairs
  • OFFSHORE-Azimuthing thruster Exchange

A letter from Rick Shilling, Sales and Marketing Director, SubSea Solutions Alliance:

With the end of March finally upon us, we are welcoming spring.  With the welcoming of spring comes the release of the ice from the North.  Ice and propellers seldom make good company so the Subsea Solutions Alliance Propeller repair diver / technicians have remained very busy globetrotting from country to country cold straightening large bends in propellers and restoring damaged propellers to operational mediums. In addition to propeller work, shell plate repairs, thruster repairs and routine inspections and husbandry has been performed keeping the global shipping and Offshore fleets lean, mean and green!

February and March 2011 proved to be a very busy time for the Subsea Solutions Alliance diver Technicians.  Work was performed on almost every continent (Except Antarctica) performing all types of routine and complex repairs.   As a continuation from January, the Subsea Solutions Alliance remained very busy in the commercial shipping, cruise and offshore sectors providing diver / technicians for the critical repair and exchange of azimuthing and tunnel thrusters as well as maintenance services like hull cleaning and underwater surveys.  Reacting quickly to emergencies, mobilizing quickly to remote locations like West Africa and providing manufacturer and classification approved repairs is what differentiates the Subsea Solutions Alliance from all the rest.

A small summary of major projects performed by the Subsea Solutions Alliance include:

    * 4 Azimuthing thruster installations- Offshore fleet- Curacao
    * 1 Tunnel thruster Hyperbaric repair- Offshore fleet- West Africa
    * 1 Tunnel thruster Hyperbaric repair- commercial fleet- South Africa
    * 2 Tunnel thruster exchanges- commercial fleet- Europe
    * 2 Stabilizer fin repairs- cruise fleet- Caribbean, USA
    * 1 temporary shell plate repair- military fleet- Gulf Coast, USA
    * 1 temporary shell plate repair- commercial fleet- Central America
    * 1 permanent shell plate repair in accordance with ABS requirements- commercial fleet- West Coast, USA 
    * 2 seal repairs- 2 cruise vessels- Australia (2 different locations)
    * 1 Hyperbaric seal repair- commercial fleet - East Coast USA 
    * 2 Fixed Pitch Propellers- repaired- commercial fleet- Europe
    * 1 Fixed Pitch Propeller- repaired- commercial fleet- Middle East
    * 1 Fixed Pitch Propeller- straightened- commercial fleet- Far East
    * 1 Fixed Pitch Propeller- straightened- commercial fleet- East Coast USA
    * 1 Fixed Pitch Propeller- straightened- megayacht- Caribbean
    * 1 Fixed Pitch Propeller- repaired- commercial fleet- Central America
    * 1 Fixed Pitch Propeller- modification repair- naval fleet- Far East 
    * 1 Fixed Pitch Propeller- modification repair- cruise vessel- Florida

 It is always interesting to take a look back to "where you have been" and this month we feature some "state of the art" equipment utilized by Parker Diving Service in the early days of commercial diving and ship's husbandry.  While digging through the archives that sometimes collect in one's office, my colleague found this old article highlighting the expertise and innovation of Parker Diving Service in the "early days".  Yes, since 1945, Parker Diving Service has been putting diver / technicians in the water performing routine maintenance and complex repairs to ships of all shapes and sizes throughout the world.

Parker Diving Service- the early days

We continue to enjoy the opportunity to bring our customer focused service, innovation and drive to meet your needs.  Thank you for your continued trust and support and we look forward to remaining valued partners with you long into the future.


Keep those props quiet- You're scaring the fish


Underwater Propeller performance improvements  

Singing propellers can be an elusive and challenging problem to fix. All propeller trailing edges develop a shedding vortex but when the frequency of these shedding vortices coincide with the natural resonance of the propeller blades, the propellers will vibrate thus causing an iritating noise called "singing".  When singing propellers involve research vessels, the problem delivers unimaginable consequences.  Considering the frustration and challenge with diagnosing the problem, developing a permanent fix requires experience and expert propeller knowledge.

As the earthquake and ensuing tsunami ravaged the Japanese northeastern coastline, our subject vessel was steaming toward this general location.  Upon notification of the disaster ensuing in northeastern Japan, our subject vessel found itself changing course and steaming toward a safe haven in a southern Japanese Island. With specialized repair gear in flight and propeller / diver technicians mobilizing for this repair, the Subsea Solutions Alliance from Vancouver, Canada found itself in yet another challenging dilemma as gear was already mobilized to Northern Japan.  Working closely with the client, our logistics team within the Subsea Solutions Alliance was able to alter course and meet the vessel with minimal or no delay.

Engineered solutions for "singing" propellers is not a consistent science.  There is no one edge design that can be applied to eliminate this phenomenon and it typically requires advanced knowledge of propeller geometry and hydrodynamics to conduct repairs efficiently. It is the experience of the Subsea Solutions Alliance that vessels with multiple propellers are more likely to be affected by this vibratory induced propeller noise and through the execution of a sharp properly angled grind to the affected edge a successful repair can be performed. The Subsea Solutions Alliance maintains hydrodynamic engineers on staff that work together with our highly experienced senior propeller engineers to perform these types of critical repairs. 

As the Subsea Solutions Alliance  had experience with this class of US Naval research vessel, a repair solution was already in hand. As the operations engineering staff within the US Navy and maritime administration had excellent experience and results from the Subsea Solutions Alliance on previous propeller repairs, the proposed engineered trailing edge modification was accepted. After less than 1 day in the water, the diver / propeller service engineers  from the Subsea Solutions Alliance executed the modification to both affected propellers. Upon completion of the sea trial, the propellers were as quiet as can be and the research was again back to normal.

With all that noise nothing could be heard; thankfully solutions are available through the expertise of the Subsea Solutions Alliance.  We all hope and pray that solutions are available for the country of Japan.  With all of the hardship and loss in the country of Japan, our thoughts and prayers go out to everyone affected by this horrible tragedy and we yearn for a quick longstanding solution for them in the very near future. 



Permanent Shell Insert Repair- West Coat USA 

While on a trans-Pacific voyage from Oakland to Yokohama, a normal inspection of the ballast tanks on a container ship revealed a 300mm fracture in the side shell plating on the port side.  The US Coast Guard and ABS attended an inspection in Yokohama and allowed a temporary repair be performed to this affected plate to allow the vessel to return to the west coast of the USA with a condition of Class.  Upon it's return to the USA, the Subsea Solutions Alliance Long Beach office was immediately set in motion to make a permanent shell plate insert repair without causing any delay to the vessel's schedule.  As this vessel was in a very tightly scheduled liner service delays were unacceptable to the vessel operator.

The Subsea Solutions Alliance had to mobilize a team of diver / welders up the California coast to template out a proper cofferdam on one of the affected vessel's sister ships.  Using the exact measurements and frame orientation provided from the inspection dive performed in Yokohama together with the template development dive on the sister vessel, the diver / welders discovered that the vertical fracture was adjacent to the toe of the leading edge of the port bilge keel.  Therefore, the template measurements were made precisely so the cofferdam would effectively seal over the forward section of the bilge keel once installed.  With the template in hand, the Subsea Solutions Alliance diver / welders returned to the Long Beach California office where the in-house Subsea Solutions Alliance engineering department developed the technical drawings and assembly drawings of the cofferdam for fabrication.  Floatation was added to the cofferdam for fast and easy installation once placed in the water.  When the vessel arrived, the Subsea Solutions Alliance diver / welders conducted a cofferdam test fit to ensure a proper fit would take place on the affected vessel.  The slot in the aft bulkhead of the 8-foot (2.44m) by 4-foot (1.2m) by 3-foot (0.91m) cofferdam made a perfect seal over the bilge keel. 
Maersk Cofferdam- Complete

Once the vessel was available for repair, the diver / welders immediately installed the cofferdam and pumped it dry without delay.  The inside technicians then cut the hole and entered the cofferdam to prep the exterior of the hull and installed the ceramic backing strip for the new insert plate.  Working together with Oceanwide Repair of California, the Subsea Solutions Alliance and Oceanwide Repair have received an approval from ABS for a single sided ceramic backing plate weld procedure for permanent shell insert repairs.  The plate was installed, welded and tested in the presence of an ABS surveyor.  The divers then removed the cofferdam and dressed up the outside of the hull to complete the evolution. 

The ship departed on schedule with a permanent repair and the condition of class was removed.  Once again, the Subsea Solutions Alliance team did what was necessary to get the vessel back in service on time and without delay to the complete satisfaction of the customer, the US Coast Guard and the American Bureau of Shipping.  Solutions is in our name and delivery without delay is our game.


Who needs a Crane barge anyway!  

Azimuthing thruster installation without a crane barge

Drill ships, dynamic positioning semi-submersibles, and other high value offshore vessels are finding the southwestern Caribbean Island  of Curacao a very convenient and well suited location to perform offshore vessel maintenance and repairs.  With crystal clear water in a DEEP WATER sheltered harbor Curacao has been the location of choice for large international offshore operators for azimuthing thruster exchange, overhaul, and other vessel equipment, hull maintenance and repairs.  As Curacao is the gateway to either the Brazilian offshore market to the south or the Gulf of Mexico to the North, Curacao offers excellent connections to either Europe or North America through it's close affiliation with The Netherlands.  The Subsea Solutions Alliance has maintained a permanent presence in Curacao for over 15 years and has substantially expanded the location to include numerous boats, support barges, heavy lift crane barges and diver / technicians to support equipment repair and exchanges.  

Large Demountable Thruster- Curacao
40 Ton thruster prepared for Re-installation

Considering the dive conditions, the availability of significant local resources and our clients continued interest, the challenge for us to find alternative methods for exchanging large azimuthing demountable thrusters, the Subsea Solutions Alliance has taken the opportunity in Curacao to develop and demonstrate advanced buoyancy control solutions for the exchange of large demountable azimuthing thrusters WITHOUT the need of a crane barge.  That's right, who needs a crane barge anyway?

The fact is the ocean is the largest crane you could ever imagine.  Think about it, the ocean lifts ships out of the water all the time, so why not harness some of the oceans lifting capacity to move a thruster?  Additionally, drill ships, semi-submersibles, and other offshore construction vessels are "one big crane", so the customer's already have cranes available, why not use them?  With this simple thought in mind, the engineering department at the Subsea Solutions Alliance has developed advanced procedures and installation specific dive plans to demount, exchange and remount large azimuthing thrusters (up to a weight of 120 tons) without an external crane barge.  These procedures have proven that the repair time can be reduced, the cost of the exchanges is considerably less and the process is less dependent on the sea conditions and weather.   

The Subsea Solutions Alliance has performed many thruster exchanges to date utilizing these advanced buoyancy control solutions.  With experience and a proven track record, the Subsea Solutions Alliance  can perform these thruster exchanges in-shore or offshore, faster, for a lower cost and more efficiently than the traditional method with a crane barge.  Considering the sensitivity a crane barge has to weather and considering the risks when performing heavy rigging in harsh environments, the advance buoyancy control solutions developed by the engineering department of the Subsea Solutions Alliance are less weather dependent than conventional methods employed today.

We look forward to the opportunity to support your needs and talk with you further.  Developing safe, cost effective and reliable solutions is what the Subsea Solutions Alliance is all about.  Let the water work for you.  Employ our advance buoyancy control solutions and see the results!  

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