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BC's Noisy New German Ferries

Louder than previous models, they rattle some coastal residents' homes.

By Andrew MacLeod 15 Dec 2008 | TheTyee.ca

Louder than previous models, they rattle some coastal residents' homes.

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Some call new C-class ferries 'Coastal Thunder.'

Eleven of 36 households surveyed through the Departure Bay Neighbourhood Association said they were disturbed by noise from the new ferries.

Kelly Franklin, who lives in the area five kilometres north of downtown Nanaimo,* circulated the survey last April among his neighbours, some of whom live as much as a couple kilometres from the terminal. He shared the results with B.C. Ferries, he said, but has not previously released them publicly.

Franklin provided a summary of people's comments to the Tyee, but with names and other identifying information removed.

Noise and vibration, along with fuel consumption, are problems related to what may be design flaws with the three new vessels, bought from German shipyard Flensburger Schiffbau Gesellschaft at a total project cost of $542 million.

The ships, the last of which was put into service in November for no more than two afternoons a week, have been spending more time at the dock than carrying passengers. B.C. Ferries is yet to fully explain why.

'Rumble keeps me up'

"Yes, the noise from the new ferry disturbs me, but only when it is in port," wrote one neighbour. "The morning rumble wakes me up and the evening rumble keeps me up; I recently travelled on the first sailing and the vibration was unbelievable in the boat."

The noise level while the boats were moving had improved, the person wrote. "I am grateful as our whole house vibrated when they came in. I had a concern about the disturbance of the soil stability but that issue doesn't seem to be an issue now."

"The new ferries are definitely much louder than the old ones," wrote another respondent who lives a kilometre from the terminal. "We can at times feel vibrations from the engines that make our house doors rattle and on one occasion -- while the ferry was revving up its engines as it sat at the dock -- the noise was almost as loud as that of a helicopter."

Yet another wrote that the "Coastal Thunder" coming and going was "turning the entire Departure Bay basin into an industrial noise area."

Other respondents said the noise did not bother them and they didn't think people should complain. "We would be unhappy if complaints from our neighbourhood association were to cause the new ferries to be moved to another route so please proceed with caution," wrote one.

After Franklin forwarded all the comments to B.C. Ferries, he said, the company sent technicians to measure noise, but failed to tell residents what they found. "I've never heard back from them. I've never heard from them at all." The noise continues, he said.

High prop can cause noise: engineer

B.C. Ferries has said it is working on ways to reduce the noise and vibration from the ships. In the summer the company reportedly added new mufflers to the engines on the Coastal Celebration and said that helped enough that they would be doing the same with all three.

Then a few weeks ago, The Tyee reported, the company performed an unusual test using as many as 18 gravel trucks to weigh down one of the vessels. The company is yet to say whether the full load helped. Nor is it clear how adding weight permanently to the vessels would affect fuel consumption should the company decide to do that.

The test points to the suspicion that the noise and vibrations are related to how high the ships sit in the water.

It's a theory confirmed by Stefan Krueger, an engineering professor at Hamburg University of Technology, who helped design the new ferries. When the ships are at berth, the propeller may draw some air, said Krueger in an e-mail. It is "absolutely harmless for the ship or the propeller, but it can cause some noise," he wrote.

Once loaded and underway, the propellers will be "sufficiently submerged" to prevent the problem, he said.

In an essay on the design of the new ferries, Krueger and two co-authors describe how the propulsion system was chosen.

They chose "a propeller diameter as large as reasonably possible," arriving at five metres. They based the size on the maximum draft of the ships, the amount of the hull that would be under the water line when fully loaded. That maximum draft is 5.75 metres.

Twenty centimetres below

When the ship is unloaded, however, the blades come much closer to the surface. According to one analysis, when unloaded, the draft is just 5.2 metres, so the blades would be within 20 centimetres of the surface.

Or as an FSG employee, Markus Brinkmann, put it participating in a web forum discussion of the Tyee's first article on the design problems with the ferries. "When the Coastals are in the dock, the propellers suck air -- yes, no doubt." It won't happen while they're moving, he said.

It is also key that the propellers turn at a constant speed of 127 revolutions per minute, even when docked. Krueger said in an e-mail that he does not consider a long idling time "normal or useful, because of the related fuel consumption." He did not, however, respond to a further e-mail asking how long would be needed to shut down the ship and start it back up again.

And as neighbours of the ferry terminals like Franklin in Nanaimo know well, the ships on the major routes spend a significant amount of time empty at the dock. They are there when they start in the morning, when they shut down at night and for 25 or 30 minutes while unloading and reloading between hour and a half crossings.

The ships came with a two-year warranty and FSG had to meet standards for noise, vibration, speed and fuel consumption or B.C. Ferries could have rejected them. Officials from both companies have said the ships met all specifications during sea trials.

Altogether the problem appears bigger than B.C. Ferries officials are admitting, Franklin said. "I think there is quite a fiasco here. They didn't do their due diligence with this design."

And as more than one ship builder said in background interviews, if the problems with the new ferries were easy to fix, they would have been fixed by now.

*Correction made at 11:20 a.m., Dec. 16, 2008.

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