El Faro Stablity


#41

What actually happened to either ship is, to some extent irrelevant with regards to certain specific points.

Even assuming that the Edmund Fitzgerald was 100% navigation error it’s still not a good idea to load bulkers deeper and deeper as they get older. In any case if it did strike bottom the extra cargo weight didn’t help.

In this case the CG ruling that converting the El Faro to RO-CON was not a major conversion was an error. The fact that Davidson drove the El Faro into the eye wall of Joaquin doesn’t change the fact


#43

As far as I am concerned intact cargo ships should be stable at departure and arrival. If the hull is damaged for any reason at sea and water leaks into the hull, it is better to prepare for abandon ship, as the damaged cargo ship can capsize and sink any time.
In is only ships carrying more than 12 passengers that are subject to damage stability regulations in order to survive hull damages flooding one and two hull compartments. But even such passenger ships will capsize and sink when the hull is damaged, when watertight doors are fitted and left open - http://heiwaco.com/news8.htm … If it happens, it is the fault of the Master and the best solution is to jail the poor sod!


#44

This is from the day 2 hearing February 7, 2017.

Examination of Jaideep Sirkar by Dr. Stettler.

Sikar: - This standard, this rule, this criterion in 170.170 of initial GM, has been applied successfully for many years now, for both – for cargo ships. However, with time, the proportions of ships have been changing and ships that, while meeting the initial GM criteria, but for other reasons such as relatively low freeboard or perhaps other proportions, they would not have sufficient stability beyond the initial small angles of heel even though they met the criterion. So there was a rulemaking process to complement this initial GM criterion with additional criterion similar to what is contained in the 2008 Intact Stability Code of IMO. So the Coast Guard proposed additional standards within that Section 170.170.

As part of the rulemaking process, in the final rule stage, the Coast Guard determined that that proposal would be not implemented. There were comments made and the Coast Guard generally agreed that while the stability standards in 170.170 could possibly be improved with additional criteria related to righting levers, in the final rule stage, the Coast Guard did not implement what was proposed, and it is all there in the record.

It seems that the USCG never implemented more stringent rules also not for ships with a low freeboard like the El Faro. I wonder why?


#45

That’s a good find.

GM is the initial slope of the GZ curve.

Here’s the El Faro’s righting arm and GM.

image

In this case the El Faro has a higher GM (4.28 > 3.50) than the cargo vessel circa 1960s but the cargo ship has a much better GZ curve.

I wonder if adding that permanent ballast increased the GM enough to allow the load line to be moved?


#46

Initial GM is no so very important. You may have an initial GM that is fairly high, but you may not have enough righting energy under the righting lever curve like in the El Faro’s curve.

Stettler observed that if she had been built this decade, the El Faro would not have met the stability requirements. She sailed with a GM of 4.3 feet, satisfactory under SOLAS 1990. However, under SOLAS 2009 she would have been required to maintain a GM of at least 5.8 feet and that is a different story.

You would expect that the load line had to be moved, that is not clear.


#47

I agree. It’s the dynamic stability that is important. I think that some of the practices we had in the past have been obscured by the use of computers . The fast turnaround of ships makes the use of computers necessary but we lose in completely understanding our ships condition.
The days of making an assessment of the sailing condition with a Ralston table then calculating the actual condition armed with a pencil and mathematical tables are behind us but so is a deeper understanding of what the computer is telling the user.
Try asking a junior officer what is meant by “winging out the weights.”


#48

I could not agree more. Using programs like Cargomax is maybe efficient, a quick fix, but you loose more or less contact with your ship, puts you at a distance so to speak. You are feeding numbers into a black box and out rolls a result…

IMG_2515

Those were the days my friend.

I also have a theory that the feeling for the sea is inversely proportional with the height of the bridge wing. The farther away from sea and waves the less respect we have for it.


#49

It is the basis for compliance with 46 cfr § 170.170, that’s why it is relevant to this thread.


#50

Of course the GM as such is an important basic 170.170 and Solas requirement, I should have phrased it differently. It was only meant to relate it to the importance of the righting energy under the righting lever curve.


#51

Yes the initial GM is important and the minimum requirement is there for a reason. But no one will thank you for having it too high and slinging the pianist and piano across the dance floor on a cruise ship, never mind the Chief Engineer moaning in your ear about the load on the stabilisers.
The shippers of flat screen TV’s are unlikely to thank you either. You know, that 40 footer of 8 tonnes on the top of the stack.


#52

Your picture reminded me of a voyage across the Great Australian Bight. We were marooned amidships with the bar and the engineers were stuck aft with the food. Guess who was more upset.


#53

As junior officers we attended the first table at 12.00 hours. In bad weather we had to sprint between waves from the midship to the aft house. Most of the engineers were then glued to their cabin windows to see whether we were drenched in the process and the little sadist were disappointed if we were not. Well, no TV or other amusement available.

The captain had his own way of going to the second table, he simply ordered the bridge to make a turn so that he could stately cross the cat walk. That was not fair…:slight_smile:

This particular ship which was tossed around quite a bit in bad North Atlantic weather and sometimes heeled 30° - 35°, at the end of the roll had the habit of hanging there for what seemed an eternity before starting upright. Newcomers on board were often shocked, thought we were about to capsize. That behavior is a sign of a small GM.


#54

From the same hearing as before.

Dr. Stettler: - Can you offer any insight as to why a container Con-Ro container roll-on, roll-off vessel such as El Faro, why that container load might pass the severe wind and roll criteria such as this but would not pass a general righting arm criteria?

Jaideep Sirkar: - I really cannot. I did not study that particular hull form. It was not a traditional container ship hull form. It didn’t have container cells. It had containers on deck and Ro-Ro decks, and again, I haven’t compared the hull form and the proportions of that particular hull. I cannot give any insights in that particular outcome.

That is a good question. I donot know whether in the mean time JS has studied this particular hull form because I am curious about his findings.


#55

I think, transforming an existing RoRo into a RoCon/ConRo is an operation against common sense.
Stowing the densely packed containers on top of the loosely packed vehicles and trailers is a port handling necessity, but also a stability nightmare.

Packing a lot of iron ore in the double bottom and elevating the load line may satisfy the static stability criteria; at the cost of eliminating nearly all ballasting options.

However, having the big weights at the lowest and at the highest points of the ship will influence the dynamic stability, the rolling behavior. The latter may be of utmost importance in the confused seas and extreme winds near a hurricane’s center.

Even worse, if the ship has a ‘temporary natural’ heeling due to cargo shift, seawater inside and/or wind force; seen from the ship, she does now roll around her new ‘naturally heeled’ vertical centerline…

The videos of the heeled and rolling PCTC ‘Modern Express’, towed in the Gulf of Biscay were impressive.


#56

From NTSB p 196

The vessel was not required to comply with SOLAS requirements
before or after it was lengthened in 1993 because it was in domestic service. The ship’s 2010 entry into the Coast Guard ACP, which was retroactive to 2006, subjected it to the equivalency requirements that are developed by the Coast Guard and classification societies (which inspect ACP vessels) and are intended to assure that vessels satisfy both SOLAS and federal regulations, as appropriate.

The El Faro was required to meet international standards for a load line certificate, U.S. to San Juan is considered to be an international voyage by load line regulations.

As far as the rest, after 2006 it was required to meet equivalency requirements, which I assume means CFRs written as to be SOLAS equivalents.


#57

Something is wrong with USCG regulation. It should not be so difficult figure out what regulations apply or why.

Regulations should make clear what is a major conversion and what isn’t. There should not be so much room for errors in interpretation.

Regulations should be clear that, at a minimum, SOLAS does apply to coastwise and ocean ships.

In fact, since we are paying more through subsidies and preferences, US ships should meet the highest standards that are second to none.


#58

The purpose of 46 CFR 170.170 - Weather criteria seems to be able to differentiate between GM’s for ships trading on the Great Lakes in summer and winter, in exposed and protected areas and on oceans and therefore has to be kept alive… A geographic situation which is uncommon elsewhere.


#59

3 posts were split to a new topic: PCTC/PCCs and Stabilty at Large Angles of Inclination


#60

From the same source a question about the possibility of extrapolating the 50 knot wind and rolling criteria to 80 knots. Sirkar, he knows his stuff, gives the only possible answer and that is that nobody knows and also that there is no such thing as a steady wind under these circumstances. Also IMO says no, we donot know otherwise we would have provided ruling for that. Beyond that point it is unchartered territory, everyone for himself and everything is depending on countless unknown possibilities. Nightmarish…

Q. Thank you. I’m sorry. There’s one other matter I’d like to add. There are published explanatory notes for the 2008 Intact Stability Code that are not part of the exhibit, but in those explanatory notes, there is a discussion that the wind pressure that is applied as part of this severe wind and rolling criteria is based on a 50-knot wind. And I’d like to ask, in light of the response that you just gave, in terms of the general, you know, what you can take away from a vessel that just meets the criteria. For a vessel in any knot winds, you know, is there any extrapolation that might – that has been considered in terms of survivability of a vessel based on a different wind speed in these conditions, or is it basically like you said in your previous response, that there’s no way to quantify or extrapolate?

Sirkar: It is not – in my opinion, the way the regulations have been developed, it is my opinion that one cannot and one should not extrapolate or predict the behavior of the vessel in an 80-knot wind because the requirement is for 50 knots, and using that requirement, extrapolate and try to predict. Again this is a steady wind. In real life, there is no such as a steady wind. This is a surrogate, if you will. This is my word. It’s a representation of – it’s a simple, simplified representation of a statistical distribution of wind speeds and gustiness of the wind and other characteristics of the wind. So it’s a measure of – it’s a steady wind pressure. It’s a measure of a certain – a simplified measure of a certain set of conditions that are again statistically studied, as explained in the explanatory notes that you just mentioned.

Just to give an idea. Wind pressure at 50 knots is 6.4 psf and for 80 knots 16.4 psf, an increase of 2.6 times that is because it depends on the wind velocity squared.


#61

Here is a link to the testimony above. Hearing 3 day 2

The day beforeHearing 3 day 1 - JEFFREY STETTLER, Ph.D. a Ph.D. in the field of naval architecture and marine engineering. - Starts on page135

Following the capsizing and sinking of eight offshore supply vessels in the Gulf of Mexico between 1956 and 1963, it was realized by the Coast Guard that vessels like offshore supply
vessels, with larger beams and lower freeboards, could have large GMs, and easily meet GM criteria but have comparatively low range of stability and area on the righting arm curve, or righting energy.

As a result of this series of capsizings, the Coast Guard began to apply more stringent stabiity criteria to offshore supply vessels, adapting criteria based on righting arms. These criteria are generally applied, in 46 Code of Federal Regulations Section 170.173, to vessels under 100 meters in length, or for other vessels of unusual proportion and form. But these righting arm criteria were not applied to larger cargo vessels, which remain governed by the GM criteria of 46 CFR Section 170.170.