My awkward attempt at satyre :
Suspect if what is below was investigated by same institution most probably the report woulld be similar.
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Agree. Many questions. What is background of investigators? They crank out these mini-reports and appears quantity and not quality is the objective. Why is this allowed to occur. When they record interviews they do not follow up. Why? It also is clear that NTSB has lost focus on difference between probable and proximate cause. Time to go back to school. Board members are bringing aviation bias to many of these investigations. Sorry but aviation and maritime are not the same.
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A squat question to the professionals. It has been a minute for me. But from memory, As the underkeel clearance decreases, so does squat. As ship approaches saturation speed, it just shakes, it stops squating and won’t go faster.
Have I been wrong all these years ??
No, that’s pretty much how squat works. The ship will only go as fast as it can go with the water available.
All of those squat formulas are bullshit, because if they weren’t, ships would be aground every day on every channel in the world.
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exactly - thanks
I would firstly say and agree that no one believes the magnitude of squat in squat tables but everyone believes in squat.
I also believed that it would be almost impossible for a ship to squat so much that it would touch the bottom as I imagined you cannot compress water ( although if squatting you would contact a peak, the sea bottom is rarely flat and uniform).
However I visited a tank testing facility which tested surface ships and also submarines ( did not see anything I should not have seen) and they told me that they could run submarines close and fast to the bottom of the tank that they would actually touch the bottom due to squat.
Therefore, yes I do believe that you could squat down enough to scrape the bottom if fast enough and with low UKC but also that you would shake and vibrate so much, hopefully you have taken action before that point.
In order to maximise cargo throughput and to stop grounding due to swell at the entrance we employed a Dynamic UKC system. Prior to commissioning, the system needed to be calibrated which required the placement of four RTK sensors. One at the bow, one at the stern plus one on each bridge wing. We normally operated on 10% UKC static (1.5m). Maximum vessel speed for the calibration was 7 knots on a full hull form 290/45m with bulbous bow. The squat was measured at 0.8m by the bow via RTK.
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To be clear the UKC’s I am talking about, and empirically remember are on the order of 1 - 1.5 ft in a 42 ft channel. At engine speeds of about 10 kts, on a tanker block coefficient - we would just cavitate, were at saturation speed - and stopped squatting. I think also important this was Houston so a deeply dredged channel with steep banks.
Very interesting comments. Thank You.
So now dear boys and girls time for some theory and refresher/updates 
Tip of the iceberg but should be enough .
Squat Interaction The Nautiical Institute.pdf (2.7 MB)
26-UKC.pdf (4.5 MB)
INTERTANKO Guide to Safe Navigation 2017-12-13.pdf (23.6 KB)
avdances_in_under_keel_clearance_risk_management_rev70_jun2012.pdf (935.0 KB)
DYNAMIC DRAFT AND UNDER KEEL CLEARANCE A HYDROGRAPHIC VIEW IHR_26_art02.pdf (1.6 MB)
avdances_in_under_keel_clearance_risk_management_rev70_jun2012 vv.pdf (3.1 MB)
BR45-6-Ship Handling-77-96.pdf (6.1 MB)
And for Hawses and pipes the Bernoulli Phenomenon shoulld be a very familiar topic.
May be tomorrow some more serious stuff.
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Who would have thought that Smirnov is not only about vodka but about hydrodynamics . Ever Given a thought about it ?
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All good questions. The vessel had an escort tug which was untethered and escorting on the port side……..useless @ 9.2 knots. It is a modern high capacity ASD unit capable of undertaking indirect towage through a centre lead aft towline allowing it to give instant response and correction to an uncontrolled sheer. At the risk of upsetting certain parties, there appears to be a general reluctance to make fast escort towage in US waters…….if you are going to employ a tug, make it fast and put where it can best assist you under the particular navigation circumstances.
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Some good links here. It is very clever technology.
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I have more but wanted to focus more on UKC and influence of speed.
Basis this report one can not figure what is a common practice there . One needs more data from previous calls of similar sized ships , their drafts , Cb , speeds , weather, state of flood/ebb - the whole shebang.
I am asking frequently myself a question what I would do. ?? I think if one has a prospect of damaging the shore structures and the ship and a choice to potentially harm only the ship , then one would choose the ship damage.
The question is what has prompted the pilot to stay so much out of the channel when he could comfortably shave the stb side of the channel . Being surprised that with this T/D relation she was clumsy is tale telling . On every bridge there is data displayed in the wheelhouse poster . One look at it will explain clearly the ship behaviour (turning circle, stopping distance) with small UKC . Asking for dimensions after 15 minutes means he did not even look at the pilot card. Hence there was no discussion , no debate , no planning. It was improvisation that turned faul.
He says this or he says that. We do not know what was in his head then. What he says now is irrelevant as obviously covering ass is in play here.
Vsl is on voyage charter or some other arrangement and with the exception of Panama Canal the master/owners are responsible to third parties claiming this or that.
Hull is damaged insurance pays, shipyard earns , local community get jobs .Everybody is happy except the owner/master cause insurance will call the sharks like you who will leave no stone uncovered , who would exray the whole mess with relevant questions based on experience and theoretical knowledge and all known industry practicies. And the very first question is why a clearly , well dredged to well known depth without any hidden obstructions channel was not used to provide for safe navigation .??? And this question will be directed at the master.
Nobody from insurance gives a damn about pilot fault and/or actions.
Now . There was a long discussion on this forum when US and other pilots were compared. There is a different philosophy in US basis this discussions and material linked to this discussions.
Europe: the pilot is a hired Owners servant. In US it appears he serves tha LAND first protectiong it from threats and the ship is a threat , and serving the Owners is a second priority.
Have signed many pilot invoices and looked at the back side of the invoice with such a small print that one has to use magnifying glass. Denibility was the name of the game . For everything !!!. Surely they have responsibilities/liabilities but rather as the servants of the LAND unless there is some crimminal issue. I think local Pilots can explain it much better the me.
Regarding BRM ?? I posted here long time ago a speech of US big fish in piloting associacion or sb like that . It says it all about the general attitude. From my experience when you mentioned BRM shit, there was this blank stare/look of incredulity with silent message baring no further inquiries : you can not be serious captain ???!!! conveying beyond doubt who considers himself in charge here. Do not blame them .
So now is the time to focus on other bridge idiots but this for later . Who pays for the tugs?? of course the Master/Owner-many things to consider here. Port gives tugs as per custom for this and this size of ship, Pilot can advise more, but Master can also ask and demand more because he and his principal pays and he is responsible for navigation.
Nationality of the owners crew will immediately give us the clue about power distance issues -see COSCO BUSAN case, language barriers. , experience in command , courses finished etc , etc . Many things
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The Algoma Verity fore and aft drafts were 38.5 feet.
According to the report the depths along the ships track, outside the channel, were “as shallow as 35 feet”. At the time of the grounding the tide was +1.7 feet (by tidal gauge) The calculated UKC would be minus (-1.8) feet. No need to for precise squat calculations.
The channel is dredged to 40 feet. With +1.7 feet tide UKC is 3.2 feet. Assume squat (from numbers in this thread) to be between 1.5 foot to 2.6 feet (0.8 meters) gives a calculated range of UKC 1.7 to 0.6 feet.
The predicted tidal level at the time of the grounding was 3.5 feet. May have been a factor, the ship did anchor to await slack/high tide arrival at the terminal.
As far as the tug, in hindsight center lead aft makes a lot of sense, less speed, more control.
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No recommendations included in this report …….only conclusions.
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There was a request for pilot comments in this thread. I usually read the reports and comment if I have something to offer. In this case the thread just didn’t show up in my email notices (or I didn’t see it, more likely).
For those who don’t know me, I was a pilot in Houston for 30 years. Now retired.
Ausmariner expressed it nicely when he wrote that the cause of the grounding seems to be clear and not food for interesting debate. The following is more about the NTSB report and answering other comments than about the grounding itself.
1. THE CHANNEL: Throughout the comments and the report there are references to “the channel” and being outside “the channel” as if there is fault to be assigned whenever a vessel goes outside the dotted lines. There is a conceptual difference between the non-pilot’s idea of “channel” and a pilot’s mental picture of a channel. Nautical charts clearly mark an area of water in white with dotted lines that is commonly referred to as “the channel”. A more accurate term would be to call it the “dredged channel” (as Ausmariner does in his comment). It’s the part of the waterway the Corps of Engineers officially maintains, but is by no means the whole channel. The area marked by the Coast Guard uses buoys and beacons usually set outside the dredged channel. Those areas are also part of “the channel”, so already the common idea of “the channel” is expanded. For a pilot who has intimate knowledge of the transit area his/her mental picture of the channel begins with the dredged and marked channel but also includes the navigable areas outside the dotted lines and sometimes outside the markers. It is difficult to describe, but after thousands of transits a pilot “sees” the waterway like a cross country hiker sees the path in front of him - even though the underwater features are hidden by water.
I have no idea what the common practice in Philadelphia is, but Houston pilots intentionally use all the area available to them. Intentionally. The channel was designed and laid out when ships were much smaller. The pilots expanded the size of ship that could be safely navigated by judicious use of bank effect and the areas outside the Corps Of Engineers channel.
I make that observation without any intention of saying the ship was in a navigable part of the channel - obviously not since it ran aground. I’m just saying the dotted lines are only part of the picture.
2. SQUAT: I was disappointed to see repeated the outdated understanding of squat, both in the comments and in the report. In 2009 a paper titled Squat in Muddy Navigation Areas was published by Guillaume DELEFORTRIE of Flanders Hydraulics Research, Antwerp, Belgium and Marc VANTORRE of Maritime Technology Division, Ghent University, Ghent, Belgium. The paper is still online I believe. In summary they believed the local pilots who told them that squat was not a factor in the transits in Rotterdam, but no one knew why. American pilots and English pilots were saying the same thing in Houston, New Orleans and London. The researchers studied the situation and found that in channels with silt, clay and mud bottoms there is a boundary layer near the bottom of mud/water mix that becomes more dense close the the bottom. Squat does exist and acts on the ship until the hull begins to penetrate the higher density boundary layer. At that point the denser water mixture provides more buoyancy. As the ship continues to squat the buoyancy increases until the two effects cancel each other out. The hull never touches the bottom. It is important to understand that this is only true in muddy areas.
3. SHIP HANDLING CHARACTERISTICS. There is a surprisingly wide range of maneuvering characteristics from ship to ship. The same ship will handle totally differently when in ballast from when she is loaded. Two ships matched in size and draft can have very different maneuvering abilities. Without exaggerating I can say if ships were cars there are some cars that would steer like a standard sedan and some cars that would have to back and fill just to make a normal right hand turn at an intersection. There would be some cars that stop with normal braking and some that you have to stand up with both feet on the brake, blowing your horn and cursing as you approach a crosswalk - and rolling slowly through it as pedestrians scatter. From the recorded conversations of the pilots and captain it sounds like the Algoma Verity was on the spectrum in the latter category.
The NTSB displayed a significant level of inexperience when they made a point of the wind being more of a factor because the ship had cranes. Not worth mentioning. On a scale of 1-10 the cranes were a 0.02 and the 38’ deep draft was a 9.98 on wind factor influence.
Spowiednick refers to the standard bridge display of the ship’s maneuvering characteristics as though any information useful to a pilot could be found there. It is totally worthless; based on data gathered in deep water and not even dimly related to navigation in a confined channel where UKC is expressed as a fraction of the ship’s draft. No one looks at it.
Just to be constructive… I always thought the results of a zig-zag test would be useful. It is required to be completed as part of the sea trial process (although a calculated test, not in actual water is allowed. It should not be). It is on the ship somewhere but not required to be posted. We had a really terrible ship that came to Houston regularly, the JO LONN. One night on a long transit the captain and I discussed zig zag tests. He got curious and spent an hour or so digging for it in his cabin files. The results were in an obscure appendix. The JO LONN had spectacularly failed. The report noted that control of the vessel was lost on the second leg of the test.
4. EXPECTATION BIAS: A pilot would be a fool if he boarded a ship without Expectation Bias. The wind is going to set your ship downwind if it’s in ballast. A right hand propeller is going to made the ship back to port. The helmsman is going to be sleepy at 0300. A deeply loaded ship will be more affected by bank cushion. The tow you’ve never heard on the radio might need some coaching to stay on his side at Five Mile because he might not know the channel as well as the local captains. There are thousands of conscious and unconscious expectations in piloting.
Ships are like small glaciers, hard to move. If you don’t set yourself up correctly in advance it can be embarrassing at best or damaging in the worst case. Another word for expectation bias might be “experience”.
Edited to remove a duplication and formatting error.
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Thanks - a bit like what I was saying above. No where near the amount of time you did, but did more than my share of trips up the HSC, in addition to your point - I continue to believe that at a certain speed with small UKC’s - increased power does not add any speed, you just cavitate - we called that “saturation speed” and if you are not adding any more speed, you will not squat any further than you are then. A slightly different way of getting to “ you can not squat yourself aground”
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Blimey 118 from 244,
Without prejudice
What a fantastic clear and precise reply you just gave.
All my thoughts and feelings as a pilot in a major port for 23 years.
Blooming fantastic, thanks buddy 
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Tex,
Also a considered and coherent reply
Thanks
There is sooo much squit published about squat , pun intended.
So much of this was generated by the MAI B report of the QE 2 running aground on Martha’s Vineyard.
I call bullshit.
There then arose an entire industry devoted to squat, or squit as I would rather call it.
The academic mariner went into overdrive calculating formula and theories for what is really a simple thing.
Try to compress water and it doesn’t work.
Didn’t we all know that, I did when I wase a cadet WTF were the rest of you reading.
Simple things for simple sailors, If the world is passing you by too quickly you are going too fast. Slow the f##k down.
BUT
When I am on a small tanker with a freeboard of 1.5 m and The captain tells me that according to his squat tables at this speed squat should be 4 m .I call bullshit.
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I just went into a rant and I apologize.
I do not want to take anything away from that fantastic post above by 118