NYC Ferry Corrosion

This story has been hard to follow. Two days ago the NY Post said three Horizon-built ferries had misaligned keel coolers which caused galvanic corrosion. Then the next day they said that five ferries, Metal Shark-built, had corrosion problems, no mention of keel coolers, and they conflated the earlier Horizon-built boats. Now there’s a hint that general corrosion control is inadequate and aluminum is a bad hull choice. Does anyone know what’s going on here? Are these lemons or is this somehow fixable? I don’t know anything about aluminum-hulled boats.

I have been following this story closely.

There are small holes forming in the Metal Shark built boats. It appears to be galvanic corrosion. Three of the boats are at North River Shipyard in Nyack. Hornblower which owns the boats and provided ferry service to NYC is being tight lipped. They put out a cover story that said that the holes were due to sandblasting, when the keel coolers were relocated. The non Metal Shark built boats do not have this problem. It has been known to Hornblower for some time, but the USCG has called them out on it. I have not seen any of the 835s pop up on the MISLE yet.

The boats have skirts on them at the shipyard so nobody can see what’s going on. The shipyard people were forced to sign 30 page non disclosure agreements in order to get the repair work.

a New York Post photographer has photographed one of the boats and reported that there are over 40 spray painted circles on the hull where the plating has to be replaced.

This story is unrelated to the grounding of the M/V Zelinsky (another Hornblower boat) on the old pier 9. The captain spent 45 minutes trying to free the vessel with passengers on board and ended up causing more damage. The vessel sprung at least two leaks and had to be dewatered and towed.

It is also being reported that this same captain ran the same boat aground near Coney Island in April. It is also alleged that he was fired from the Staten Island Ferry for spitting in the face of one of the Assistant Captains. The New york Post has his name and picture printed.

He has Sandy Hook Pilots listed on his linked in profile. I wonder how that ended for him?


The corrosion looks pretty ugly for such new hull plating.

I’ll be interested in hearing the results of the cause (if it is divulged). Metal Shark also is delivering four ferries to Washington, DC area, and I’d hate for it to be systemic.

Don’t know what your sources are but this is being corroborated by lead reporter on these stories, Kirsten Conlay, and updates are now on her Twitter account. None of the Horizon-built boats affected.

Without revealing too much. I am one of the sources that she is quoting. I am not a NYC Ferry or Hornblower employee. As usual the cover up is worse than the actual issue here.

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Chinese Aluminum?

The way to go to avoid this problem in the future is to go to composite material for the hulls:

I don’t know if they have manage to break into the US market yet, but in Norway and China this is now the “gold standard” for fast ferries:

Link to the JV in USA:

The two soon to be replaced MTA commuter ferries in Boston are composite hulls with an aluminum deck and house. I don’t see anything wrong with aluminum so long as the cathodic protection systems in place are adequate.


As the City and Hornblower were telling the public that sandblasting caused the leaks.

Bilge alarms went off on two more Metal Shark boats and the USCG made them haul those two, as well as the last (sixth). It has now been verified that the NY Post was right all along. the whole series has a corrosion problem.

The USCG has had to make a press release.
Coast Guard conducts out of water inspection on NYC ferry

NEW YORK – Today the Coast Guard completed an out of water inspection on the ferry Urban Journey, hull number H201, one of 10 New York City commuter ferries in the 200-series fleet.
After completing a detailed inspection of the vessel’s hull, the Urban Journey was declared safe for continued passenger operations. Underwater hull inspections were conducted on all other vessels in the 200-series fleet and no structural concerns were identified.
Significant hull corrosion was recently identified on NYC’s 100-series fleet. As a result, all six 100-series vessels were taken out of service for repairs. Coast Guard marine inspectors are providing ongoing oversight of this repair work. “Our number one priority is passenger safety,” said Capt. Michael Day, commander Coast Guard Sector New York. "We required this inspection in order to be certain the corrosion problems seen on the 100-series fleet were isolated to that fleet only. Today’s inspection has confirmed that.

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They rushed that first series of boats out of the shipyard so that they would meet an “on time” delivery deadline and be able to have them in service for they ferry service’s launch on May 1. That’s why they’re all lemons, including this galvanic corrosion problem where the keel coolers are…or so I’ve heard.

I agree with Traitor, aluminum hulls can cause trouble later in life, but have a fairly good history when built properly. Composite hulls may avoid corrosion, but only time will tell how they perform long term. There was a funny quote in the NY Post article:

“An expert in boat design, marine engineer David Cooke, questioned Hornblower’s decision to use aluminum hulled boats for the NYC Ferry line.
“Aluminum’s not really compatible with salt water,” said Cooke, who works for Robson Forensic in Lancaster, Penn.”

Aluminum is not really compatible with salt water??? Isn’t that about the same as saying steel is incompatible with air?

That’s actually a true statement and was probably quoted horribly out of context.

Remember when this crap went down in the PNW?

Big problems. Wrong alloys used.

Is the corrosion concentrated around the turn of the bilge just below the waterline as seen in the first photos, or is it widespread?

There is no mention of cracking so intergranular corrosion might not be the culprit.

I wonder if there might be a problem with contamination from foreign material being crushed into the aluminum as it passes through the bender rollers during forming at the yard. A tiny speck of steel or copper, or just about anything would form a corrosion cell and rapidly create pitting.

How much welding was done on the boats after launch and pre-dilivery - or after delivery?

Sounds like it might be stray current corrosion to me - judging by the overall pattern and speed of wasting.

Are you sure these two ferries are not built from Glass Fiber Reinforced Plastic (GRP)?
If these where built in 1996 they are definitely not built from Carbon Fiber Composite sandwich, which is very different from GRP:

Carbon fiber composite is not new, it has been used for building HSCs since 2002 and has proven a durable material. Not only is it near maintenance free, but also much lighter, which means less engine power for the same speed.

Here is a 40m HSC on test in rough weather in Norway befor delivery:

The same HSC in her home waters of the Pearl River Estuary, Guangdong Province, China:

Thanks for the lecture in composite boat construction, I’ve gotten enough resin on my clothes to know the difference. The two boats in Boston are a GRP with Kevlar reinforcements to my knowledge. Yes pre preg carbon is light and stronger, it’s also extremely expensive to build, and repair. Compared to aluminum construction it has its advantages and disadvantages.


You are welcome.I’m pleased to have been of help.

There may be different ways of seen things. What is expensive in construction can be VERY economical in the long run. At least that appears to be the way it is seen when it comes to HSCs and the choice of building material. Low maintenance costs and low fuel consumption probably make up for the higher building cost (if any) over a relatively short time in operation. Lower emission also count a lot these days, both in Europe and China.

All I know is that the Carbon fiber Composite and sandwich method of construction appears to have captured the market in Norway and now in China. This Oct. another three HSCs for China was ordered. They are to be built in Norway:
A Chinese company is now also part owner of the mother company in Norway.
In the future construction for the Chinese and other Far East markets will be by a JV company with established manufacturing facilities in China.

PS> I’m not sure if pre-preg carbon is the same as the “sandwich” method used by Br.Aa :

You are so good at sarcasm…

Message me back when you’ve laminated anything in any kind of composite structure. There reasons owners and shipyards have stuck primarily to aluminum construction in the US, and northeast in particular. From build cost, to ease of repair to the color of the fucking sky. Maybe you should start a ferry company in New York, I’m sure you could get a certain naturalized citizen of Connecticut to back you.