Failed Tugboat to be Purchase by US Gov't 5

[TugboatEng]

https://www.marinelog.com/news/is-uscg-getting-serious-about-buying-chouest-icebreaker/

This is the most expensive tug ever built.

It failed it's first job. It was not able to maintain tension on its tow wire and broke the towing gear.

After the gear failed it could not keep water out of it's fuel tanks due to vents being placed too close to the waterline.

After the fuel tanks filled with water the boat was apparently not using industry standard centrifuges. It also had newly government mandated fuel filters that has no means of indication of water in fuel.

This boat was built to be a government vessel and deserves it's fate. Oddly, the govt is going to pay more than asking for their failed vessel.

Should we trust the US Gov't with our oil prices?

 

[IRstuff]

Your cite makes no mention of failures

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

faq731-376 forum1529 Entire Forum list

http://www.eng-tips.com/forumlist.cfm

 

[TugboatEng]

Sorry, I forget this is a niche industry.

I'll start with the least sensationalized source and we can go from there.

https://www.google.com/url?sa=t&sou...oQFnoECDAQAQ&usg=AOvVaw35FCkCqAgerAIusYGWB9qk

The story is a bit light. The blackouts were caused by fuel injectors failing due to water in the fuel.

The fact that the US government is looking to buy the vessel is a joke in the industry hence why the story was run.

The specification was written to force selection of the Aiviq. It is the only vessel in the world that meets the oddly specific requirements. With that said, the Aiviq does not have the capabilities of the Polar Star and is not a replacement. It is not a true ice breaker.

 

[spsalso]

With global warming, it would seem the need for ice breakers would be diminishing.

Perhaps investing in desert land-crawlers might be the way to go.


spsalso

 

[TugboatEng]

Can you be consistent with your misinformation? I thought everything was going to be inundated by sea level rise.

 

[Sparweb]

The NTSB report reads like a movie plot synopsis. No happy ending though.
This one also doesn't read much like an air accident investigation report (which I'm more familiar with). Yeah, they are different machines, but the thought process of investigators, the conditions of the weather, the failings of humans, the failings of materials, and "lining up the holes in the swiss cheese" really aren't any different in any accident.

Puzzled by this passage:
...the source of the fuel contamination was outside the scope of the NTSB’s investigation of this accident and, therefore, was not determined...

Huh? That is regularly in the NTSB purview when they conduct aviation accident investigations that may possibly be traced to a fuel problem. Something in the establishment of this investigation seems odd, given the number of players at the Coast Guard hearings. In which the NTSB "participated". Did the CG not give the NTSB adequate authority to investigate this accident? Was there a jurisdictional tug of war? (forgive the pun)

Next surprising quote:
For this reason, Shell, as the organization responsible for designing, approving, and implementing the tow plan, is considered to be ultimately responsible for this accident.

When did the NTSB get down into naming and shaming? Usually their investigations are clear on the cause, but don't assign the responsibility (even when it's blatantly obvious). Especially in this case where they were giving testimony to a board of inquiry - it's the board's job to assign blame.

Part 49 explains the breakdown of authority for maritime accident investigations:

https://www.govinfo.gov/content/pkg...le49-subtitleII-chap11-subchapIII-sec1131.pdf

That's a bit down in the weeds for me, though. Maybe you'll find it useful.

 

[Alistair_Heaton]

I was thinking the same thing Sparweb.

With Aircraft stuff even if not mentioned in the investigation there are a series of automatic evidence collection procedures started in relation to fuel. The paper trail goes all the way back to the refinery acceptance of raw materials.

Was quiet amazed reading a report about a maint finding on part which failed in service related to fuel (injectors) and it ended up being linked to 5 fuel batches being produced 10 months before and used to fill 90 odd aircraft. The bulk of the aircraft were fine that were turbojet. The turboprops which there was 5 different engine types both fixed shaft and free turbine all had to have remedial maint.

It was a surprise to me they seemed to be able to relatively easily track back to origin and then expand back out and pull the data/evidence on the other exposed aircraft.

It was very early on in my career when I read it, later on I went looking for it to use in a multi discipline CRM course involving technicians but for the life of me I couldn't find it.

A secondary injector fractured and came off into the combustion can when the power was reduced to flight idle and resultant lump went into the HP turbine. There was no problem with the primary injectors just secondary injectors on TP's. It was a chemical induced fatigue issue.

To note on TP's they use secondary injectors during start and beta prop angles on some types of engine. Some have engine purges after shut down to blast air through them to clear fuel others don't. At that point in my career I was more concerned about flying in a straight line and saying the right thing on the radio than what was going on in the engines. These days what the various systems do and how they can fail knowledge is more of a life time hobby. It doesn't need to be about aircraft I have flown or even likely to fly. An inflight failure of a 70 year old glider is just as interesting as what went on with the MAX.

Also I can't quiet work out how an injector departed into the combustion can. Which is another reason why I want to find it again.

 

[TugboatEng]

I guess one could argue that the fuel contamination was not the cause of the loss of the tow and is therefore outside of the scope of the investigation.

Here is the more thorough investigation that details some of the vessel engineering issues.

https://www.google.com/url?sa=t&sou...FBAWegQICBAB&usg=AOvVaw3lmxOV9q4dL-5SSwXChPRM

Head to page 99 for the source of water in the fuel.

 

[Factoter]

The Dept.Defense estimates ice-free arctic conditions possibly by 2040’s:

https://media.defense.gov/2019/Jun/06/2002141657/-1/-1/1/2019-DOD-ARCTIC-STRATEGY.PDF

As an aside, not often mentioned is that icebreakers need ice in order to clear passage for shipping. When yearly ice breaks up, passage becomes too dangerous from free-floating ice, and so a melting arctic scenario entails an arctic that is less navigable, not more. The trend has been the loss of the multi-year ice pack, but not single year ice, which is generally increasing, and which allows for the icebreakers to perform their intended role.

 

[FacEngrPE]

This purchase seems to be a stopgap, perhaps resulting from troubles in the icebreaker construction program,

As New USCG Icebreaker Breaks Shipyard, Bollinger Expected To Take Over Halter Marine; Nov 6, 2022

 

[Factoter]

?Tug: thoughts on why these injectors failed from water?
Ive heard of three or four possible explanations, . . . But recognize it’s trivial point,
Unless the designer intended the ships engines to be water-boosted?

(Edit) CoastGuard report says it all, with photographs, injectors seized.
Not the answer I expected.

 

[TugboatEng]

The engines on this boat are unit injector types. There are a few things that happen when an injector gets water in it.

The first is that the nozzle will fracture and break off dumping fuel into the engine. Or, the valve can get stuck in the open position from corrosion/galling. Both of these will cause excess fuel to dump into the cylinder. The NTSB report found two failed rod bearings which can be a symptom of oil dilution from fuel.

Secondly, the pump plunger itself can stick due to corrosion or galling. This usually breaks the rocker arm on this series of engine. Depending on the fuel rack configuration, the engine can also get stuck at the power setting the injector seized at. I don't know of any engines that have this rack configuration after the 1980's or so.

These injector components are all lap fit steel alloys and are very sensitive to seizing from any type of corrosion. Even handling the parts with your bare fingers can make them a bit sticky during assembly.

In CG report, they discuss the Racor water separating filters. Firstly, the water should have never made it to those filters. This boat has storage tanks, settling tanks, and day tanks. All fuel entering the day tank should be processed through the vessel's centrifuge and undergo multiple passes through the centrifuge. The water was there but it caught nobody's attention. In the past, the Racor filters had clear bowls on the bottom that allowed the operator to see if there was water. The CG had recently mandated metal bowls just before construction of this vessel. It still hasn't caught on that a water in fuel sensor needs to be added (available from Racor)to alert the operator of water.

 

[enginesrus]

Unit injectors? EMD?
This boat design you mention, is just what I have been constantly talking about. How CAD etc. hasn't helped as much as thought, and engineering has gone west. No common sense exists anymore in any industry.
No more old timer machinist and assembly people telling the engineers fresh out of school that their idea will not work or last. I lived that in my last place of employment, too much computer and no engineering thought process.
Sounds like that engine is not EPA compliant.

 

[TugboatEng]

Caterpillar is able to meet Tier 4 standards with electronic unit injectors in their 3500 series engines. The boat in this example uses C280 engines which are electronic unit injector fueled versions of the 3600 series. Cat released a C175 engine which was common rail and meant to replace the 3500 series. We are acquiring the tier 2 C175 boat but it is being repowered with 3500 series engines to meet tier 4 before we take delivery.

Large ships are not required to meet the highest emissions standards. Most new construction is running the equivalent of tier 2. Coastwise ships are supposed to comply with tier 4 but exemptions are issued for all new construction due to the safety critical nature of the engines. Tier 2 can be met with mechanical unit injector engines. We were operating a special pair of 6-71 series Detroit Diesel engines that were compliant with tier 2. Clean Cams Technology Systems built the kits.

 

[Factoter]

Well, here is more food for thought: (30,000t worth)

https://www.arctictoday.com/chinas-...nuclear-aircraft-carriers/?wallit_nosession=1

“They have just finished construction of two Type 272 icebreakers, which are about 5,000 tons [of displacement] and whose purpose is not yet understood,” Huebert points out. “Very little has been written on the intended use of these vessels and how they will compliment the two better known Chinese icebreakers.”

“In contrast, the United States’ Navy does not own a single ice-capable vessel and the United States Coast Guard operates a 43-year old heavy icebreaker and a more modern medium icebreaker, with hopes of commissioning a new one in the next decade.”

 

[LionelHutz]

I read this and just don't see it as such a big deal. Someone will make money fixing it, just like lots of other government "stuff".

 

[Factoter]

Tug, thanks for this link to CoastGuard report above, dealing with these vessels, it’s like a pre-Christmas, Christmas present. And the oil rig grounding was precisely 10-years, this New Year and adventure, mysterious misadventure, to read through. I sympathized with the engineers struggling to keep the new engines and power units going, under tow, in a gale, on a new ship, . .etc, etc, . There are so many details here in the report to digest.

But one question? Famous truism is that shackles never fail, while the coastguard suggests it was a weak link, at 120T, but also point to the cotter-key maybe failing as well. It seems first item is the weather, second is the shackle, and the rest anecdotal apparently.

 

[TugboatEng]

At 120 tons rating it was proof load tested prior to sale.

Another note, towing shackles are sold by the mfg with cotter pins but they're required to use bolts to secure the nut for towing. I know that stainless steel bolts are often used and that is a no no.

I work for a ship assist company so my experience is 95% soft line connection. We do towing but rarely. Our tows are not extraordinary so there isn't any engineering done. Rules of thumb are sufficient. Our vessels pull 50-96 tons.

 

[enginesrus]

I guess I'm old school Cat, in the day Cat poo'ed the unit injector and bragged about the multiple jerk pump system. I wasn't thinking HEUI sorry.

 

[TugboatEng]

Cat was way behind the curve in terms of fuel efficiency in their D398 and D399 engines when put up against the EMD 567 and 645 series engines. In tbe 1980's they moved from the inline style injection pumps to the unit injector system to support the high firing pressures needed for smoke free direct injection engines. This was the beginning of the venerable 3500 series engines.

Later, Cat made a larger 3600 series engine for trains to compete with the big horsepower EMD 710 series engines. I guess the engine sucked in so much air it would pull a vacuum in tunnels so it never really caught on in the railroad. This engine is also a unit injector engine. The electronic controlled version of this engine was renamed the C280 and that is the family of engines powering the Aiviq.

The 3600 series engine did have problems with injectors seizing during large load changes. Something to do with cavitation near the spill ports. I don't know of this problem carried over to the C280.

No HUEI systems ever made it into the large Cat engines.