Iyanough setback blamed on O-ring

Vessel engine was removed, shipped to Connecticut for repair.

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The M/V Iyanough returned to service Friday morning. – Rich Saltzberg

The Steamship Authority has blamed an O-ring glitch on the unexpected delay in returning to service the MV Iyanough, its fastest vessel. The four-engine Iyanough exited Nantucket–Hyannis service for a scheduled overhaul of two of its engines — complete rebuilds from the blocks up. During SSA sea trials on March 28, a lube oil alarm caused the rebuilt engines to power down. The Iyanough returned to the SSA’s Fairhaven facility and remained docked there for eight days as SSA personnel and technicians from the engine manufacturer, MTU, troubleshot the problem. On Friday evening, SSA spokesman Sean Driscoll told The Times the problem with the vessel had been diagnosed and cured.

“On Thursday, April 4, 2019, the No. 3 engine was removed from the MV Iyanough and transported to an Atlantic Detroit Diesel – Allison repair facility in Connecticut,” Driscoll emailed. “Later that evening, MTU repair personnel identified the problem with the engine as a missing O-ring, roughly 6 inches in diameter, that had not been installed on the engine’s vibration dampener assembly during the overhaul process. The absence of the part allowed engine oil to flow back into the crankcase. At higher RPMs, the absence of the O-ring caused the low lube oil warning that was observed last week on the rebuilt engines during the Authority’s sea trials.”

In light of the Viking Sky cruise ship calamity on March 23 in Norway, which Marine Log reported was triggered by a lube oil problem, The Times asked MTU American spokesman Bryan Magnum if there might be similar, glitchy components at play between the two vessels. Magnum chalked the incidents up to coincidence, and he pointed out the engines are entirely different.

“This does not appear to be in any way related,” he emailed. “This ship has medium-speed engines from MAN [Viking Sky], as opposed to the high-speed MTU Series 4000 engines used by the Iyanough, so the two vessels do not share any engine components. [T]his appears to just be coincidence.”

“The O-ring has been installed in the No. 3 engine, which performed to specifications when tested in Connecticut,” Driscoll said. “The engine will be delivered to the Authority’s repair facility in Fairhaven overnight, and is expected to be reinstalled in the MV Iyanough Saturday morning. Meanwhile, the O-ring will be installed in the vibration dampener assembly in the No. 4 engine, which remains installed in the MV Iyanough, this weekend. The Authority anticipates that the MV Iyanough can return to the Hyannis–Nantucket route late next week, after the vessel undergoes sea trials both internally and with the U.S. Coast Guard.”

Driscoll went on to write that the SSA thanks MTU for all its help, and furthermore thanks SSA customers for their patience.

Robert Ranney, Nantucket’s representative on the SSA board, lauded the SSA for their effort to find a surrogate fast ferry rather than cancel high-speed runs to Nantucket: “[R]ather than canceling Iyanough’s published schedule, the SSA was able to find a temporary replacement vessel and arrange to have it run in Iyanough’s place. Nantucket’s traveling public is grateful for the effort the SSA put into this, and sees this as the SSA doing exactly what it should be doing. I’ve heard no complaints about the MV Wall Street or Seastreak in general.”

Ranney also praised MTU for coming to Fairhaven to help sort out the engine problems. “The manufacturer immediately stepped in to help diagnose and repair the engines — nobody knows their own engines better than the manufacturer,” Ranney wrote.

Should sea trials pan out, Ranney expects the Iyanough to return to the Nantucket run next week.