Icebreakers

US Coast Guard Polar Security Cutters
(45,200 HP)

The Polar Security Cutter (PSC) design is an evolution of the “Polarstern II”. The vessel design is 460 feet in length with a beam of 88 feet overall, and a full load displacement of approximately 22,900 long tons.  The vessel will accommodate 186 personnel comfortably for an extended endurance of 90 days.  The PSC is to be classed Ice Class PC2 with Enhanced Polar Class Notation according to ABS Steel Vessel Rules 2018.  The propulsion will be triple screw diesel electric at over 45,200 horsepower with a center line conventional fixed pitch propeller shaft, and outboard azimuthing thrusters.  The installed power is to be readily capable of breaking ice between six to eight feet thick.  LamaLo has been contracted to provide the following services:

  1. Design Review of Propulsion System
  2. Conduct the theoretical shaft alignment and vibration analyses.
  3. Conduct the final alignment of the center propulsion shafting.
  4. Measure and assess powering performance and shafting vibrations during trials.
Delivery of the 1st vessel is planned for 2028.

CCG Terry Fox
(2 x 8,090 kW)

The CCGS Terry Fox is a CAC 4 Icebreaker, and has a twin screw propeller configuration, each rated at 10,900 HP (8,090 kW). The Fox is to undergo a Vessel Life Extension (VLE) in 2024-2025.  The objective of the VLE is to maintain the vessel’s existing propulsion capability at least until the year 2040.  As part of the VLE, new main engines and gearboxes, including clutches, couplings, Power-Take-Off (PTO), are to be installed.  The existing propulsion shafting and propeller are to be retained and serviced as required.  LamaLo has been contracted by Heddle Shipyard to provide the following:
  1. Review of proposed new propulsion system.
  2. Alignment and Vibration Analysis
  3. Final Alignment
  4. Measure and assess powering performance and shafting vibrations during Sea and Ice Trials.
The VLE is planned to completed 2025/26.
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Milled Ice Block (Size ~ 3 m x 5 m x 5 m)
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Measured Shaft Torque During Ice Milling by Propeller
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Corresponding Measured Shaft RPM

CCG Louis S. St. Laurent
(3 x 6,714 kW)

The CCGS Louis S. St. Laurent is a CAC 4 Icebreaker, and has a triple screw propeller configuration, each rated at 9,000 HP (6,714 kW).  The original propellers induced excessive vibrations, had frequent blade damages, and had poor performance characteristics.  The original mono-block Mn-Al Bronze propellers were replaced by bolt-on stainless steel blades with a higher P/D ratio.  LamaLo Technology was contracted to provide the following services:

  1. Assist in the design and operational considerations for the new propellers
  2. Conduct the theoretical shaft alignment and vibration analyses.
  3. Measure the shaft alignment condition and torsional vibration characteristics.
  4. Conduct the dynamic simulation of entire propulsion system to determine the control system changes required and the ability of propulsion system to meet performance requirements with the new propellers fitted.  LLT managed and directed the simulation work and reporting.  The computer simulation programming was sub-contracted.

The vessel returned to service and the propeller performance was excellent.  
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Stern of Vessel
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Wing Shaft
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Stern Bossing

USCGC Polar Class
(3 x 20,000 HP)

The U.S. Coast Guard (USCG) operates two Polar Class Icebreakers, the Polar Star and Polar Sea.  They have a length of 399 feet and a displacement of 13,500 tons, and are also the most powerful non-nuclear icebreakers in the world, with a maximum rating of 3 x 20,000 shaft horsepower.  Each propeller shaft is supported by two water lubricated sterntube bearings.  The bearings are a dove-tail slot stave design.  Both the aft and forward bearing materials are Thordon XL (Polymer Alloy).  The bearing shells are supported by five lands that are integral with the stern bossing.  The fit of the bearing shells to the lands in the aft stern tube has been lost.  This has resulted in increased corrosion of the lands, fretting and insufficient support of bearing housing.  The land rings have been “built up” by applying Belzona.  For this application the lands have been repeatedly undercut and boring undertaken to restore fit.  Using this method of repair has proven to be short lived and expensive to maintain.

 LamaLo Technology was contracted to develop a permanent repair and/or redesign that would effectively address the loss of fit as well as provide for a reliable bearing.  The USCG asked that the study focus on the potential of chocking the bearing shell in permanently with a suitable material.  The bearing design arrangement was examined, with particular attention to considerations for ice-class service.  The properties of potential bedding, filler (between lands), and bearing materials were assessed.  Modifications to the bossing and bearing length were also examined.

The recommended modifications to the aft sterntube bearing were implemented on both the USCGC Polar Sea and Polar Star. 

Other Work

Mr. Bruce Cowper of LamaLo Technology Inc. has worked for over 15 years on measurement, analysis, and design of ice class propulsion systems, including research work used in the development of design criteria for ice-class propulsion machinery.  This has included working with IACS on the development of Unified Requirements for Polar Ships, and with the Canadian Coast Guard / Transport Canada on revision to the Canadian Arctic Pollution Prevention Regulations (Propulsion Machinery and Powering).  Bruce has managed a number of icebreaker full-scale trials, and has extensive experience on trials investigating the performance of ice-class propulsion systems.  Trials work has been conducted in the Antarctic, Arctic, Canadian East Coast, and the Saguenay River, on more than a dozen icebreakers and on the Canadian Ice-Breaking Oil Tanker MV Arctic.  Mr. Cowper has also acted as specialized technical liaison with Russian experts on icebreaking technology in St. Petersburg, Russia.