“With both motors out of the way (the port motor removed for repair and Louis Allis motor on deck waiting for the starboard ABB motor to be installed), maintenance work could be done on an unused cooler which had a small oil leak but which could not be easily accessed with the motors in place. Taking the opportunity to gain access to the cooler, the crew blanked it off in order to stop the leak. But unknown to the crew, the configuration of the valves was incorrect. (This was an issue that pre-dated our acquisition of the vessel but did not become apparent until after the cooler had been blanked off because the cooler had not been in use.) The incorrect seating of one of the valves meant that when the starboard hydraulic propeller pitch control pump was re-started after blanking off, the system became over-pressurised and a hydraulic pipe ruptured.”
“We have disassembled the ABB motor and found a few more issues. The stator has 1 shorted coil as we discovered with the surge tester ... . In addition the stator had broken loose from the frame just like the first motor failure. We caught it in the early stages so in essence the stator was making light contact with the rotor iron. There are only 2 dowel pins that hold the whole core in place and they sheared off. As I explained to you this whole core is held in place by a few pads on a very narrow fit. If you look at pictures … you will see not a metal to metal fit but a huge gap. Had the coil not shorted and the motor continued to run you would have had a catastrophic failure.”
“… Both motors basically had 2 design problems: 1. The brazing used on the rotor bar joint to the end ring did not have sufficient build up. This allowed the end ring to develop cracks and fractures after numerous starts. Both rotors have now been repaired by Louis Allis and the proper amount of brazing has been achieved. 2. The second problem was a poor design of the stator core fit to the motor housing. You have a narrow machine surface and (4) dowel pins that were holding the entire core in place. Both cores eventually worked loose due to vibration and normal use. We have already repaired the starboard motor correctly by tightening the interference fit between core and frame and then welding the core in place. The same repair will take place on the port side motor next week. Once the port motor is rewound and the above wall performed, you will have two very reliable motors that should give you years of excellent service. …”
“This insurance covers loss of or damage to the subject-matter insured caused by ... any latent defect in the machinery or hull”
“A representation as to a matter of expectation or belief is true if it be made in good faith.”
“If in consequence of any of the following events: (a) loss, damage or occurrence covered by Institute Time Clauses – Hulls (1/10/83) .... (b) breakdown of machinery, including electrical machinery or boilers, provided that such breakdown has not resulted from wear and tear or want of due diligence by the Assured, ... then this insurance shall pay of the sum hereby insured” ... then this insurance shall pay of the sum hereby insured”
“6.2 This insurance covers loss of or damage to the subject-matter insured caused by 6.2.1 accidents in loading discharging or shifting cargo or fuel 6.2.2 bursting of boilers breakage of shafts or any latent defect in the machinery or hull 6.2.3 negligence of Master Officers Crew or Pilots 6.2.4 negligence of repairers or charterers provided such repairers or charterers are not an Assured hereunder 6.2.5 barratry of Master Officers or Crew, Provided such loss or damage has not resulted from want of due diligence by the Assured, Owners or Managers.”
“… Based on the reading supplied the week of April 13 – 16, there is a definite problem with the motor. The highest reading was 1.691 IPS. This reading is off the severity scale. It would appear that the stator core is loose in the housing. My suggestion would be to run at light loads until June. The highest reading was at 7220 CPM, which is an electrically induced vibration. This could be cracked rotor bars, unequal air gap, or looseness in the core. I can not guarantee the motor will make it until June, but it looks like we don’t have a choice. My recommendation is to do a complete diagnostic review on the motor. The motor needs to be dismantled to the point we can inspect the fits holding the core in place. There is a possibility to weld the core in, but again no guarantees until we inspect.”
“Inspection of the Port azimuth motor has revealed that the welds holding the stator in place within the stator tube are good with no signs of failure. In discussions with Louis Allis this would then tend to lead to the source of the vibration being caused by the rotor. Possibly a cracked rotor. Intention now is to have the rotor removed from the stator to allow a full inspection of the rotor to see if a cracked rotor bar can be found. It will also allow for the inside of the stator to be inspected as well in more detail. There are signs though at some stage the stator has suffered from overheating.”
“The attending manager’s superintendent advised that the cause of damage was due to cracked rotor bars to the brazed end ring attachment welds, causing excessive vibrations in operation, which caused the stator winding securing top-strips to vibrate loose, break-up and grind-up in the stator bore during operation and which was caught in time and operationally restricted thereafter to prevent more catastrophic damage occurring. The attending manager’s superintendent further advised that the earlier casualty, as reported upon in our report No. GSS 247460, regarding failure of the similar starboard thruster during October 2004, is now also considered to have been caused by a similar occurrence, vis-à-vis, cracked rotor bars to the brazed end ring attachment welds. It is the undersigned surveyors opinion that the cause of the damage of both the now report upon Port Azimuth Thruster Motor and the earlier reported upon Starboard Azimuth Thruster Motor can both reasonably be attributed as now alleged.”