Strange remark. You wouldn’t say that you are a mariner. No time even to put on their survival suits. Let’s stay positive. To build ships that can sink in 14 minutes, hole or not, is quite an achievement of modern naval architecture.
Looks like I didn’t write down everything I was thinking. My point was that I would have expected a ro-ro ship with small GM and essentially no double hull on the cargo deck immediately below main deck to capsize even faster. Of course, the hole was fairly small compared to, say, losing a bow visor in head waves…
I designed a PCTC during my studies and fondly recall the first damage stability calculations. The ship floated fine, just upside down. Later we came up an ingenious ballast tank arrangement where side damage from collision led to the ship heeling to the other side, essentially lifting the damaged area above waterline for repairs…
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In case anybody is looking for an explanation as to how to navigate inherently unstable ships then superior skill should not be ruled out.
If in fact car ship stability is no more difficult than other ship types no explanation is needed.
An old article about the Cougar Ace. It was done in very difficult conditions but salvors righted the Ace simply by ballasting.
Reed’s calculations show that the fifth starboard ballast tank has to be about 20 percent full to bring the Cougar Ace all the way up, and as water begins to pour into the tank the ship starts to come off its 60-degree list.
Righting the Ship
The Titan Salvage crew built a digital model of the Cougar Ace so they could develop the following plan for shifting water between ballast tanks (teal) before attempting to right the ship.
1. Position self-contained, diesel-powered pumps on the flooded ninth deck and suction it dry, dumping water overboard.
2. Check water level in the fifth port ballast tank (red) to ensure adequate counterbalance. Begin filling starboard ballast tank (yellow).
3. Fill the fifth starboard tank with 160.9 tons of seawater to bring the ship fully upright.
About 99% of the cars remained lashed down in place.
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Sounds like American Coastal with the Amco Voyager and the Amco Trader. It was a miracle that neither one of those ships sank. We lost the plant on a regular basis, the R2-D2 gyro went out and we steered by magnetic compass from Norfolk to Baltimore, the ship would pound and the bridge electronics would start blinking on and off, etc. etc. When we would pull into Felixstowe the longshoreman would look at the ship and say: “…Well Yank, this looks like on the U-boats missed!”
Similar topic on this thread:
Has this link
https://www.researchgate.net/publication/262731815_Cougar_Ace_The_Tipping_Point
Made a quick pass, min required GM for the Cougar Ace was 1.4 meters, calculated GM to stay upright was 0.15 meters, actual GM at the time was 0.05 meters.
The mate had to pump out 4000 tons of ballast water to reduce the GM. It took 160.9 tons to get the ship upright again.
Yes, those were the ships. I was on both of them at one time or anopther. I don’t recall ever losing the plant when I was aboard though one time I was asked to fly to Norfolk to help get the one there going again after the lights went out. Surprising given the simplicity of the steam plant.
As far as the Mates go, with the house so-o-o far forward, a miserable ride indeed. Particularly sailing to Northern Europe where I remember more crappy weather than pleasant seas.
The Cougar Ace paper uses the term “bilge ballast tanks” the more common term is double bottom ballast tanks. The paper also uses “2 Port” (2 port + 2 starboard) meaning two different sets of tanks (four tanks total) but is confusing because 2 port would be the name of a specific tank.
The conclusion of the paper here makes it more clear.
So four separate ballast tanks with a total capacity of 4000 tons was pumped out during a ballast exchange. This reduced the GM (called MG in the paper) from something close to the required minimum (about 1.4 meters) to 0.05 meters or less.
At the time the ship had about 450 tons of fuel on board, assuming consumption was 50 tons/day is about 9 days which sounds like “minimum reachable” with a margin meaning they planned to bunker USWC.
According to the calculations even pumping out four ballast tanks the incident would not have occurred if they had a few more days fuel aboard.
IIRC, the salvage video shows the cars strewn about. However, that may well be a result of the cutting and lifting process for all I know.
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Deballasting as was done on the Cougar is somewhat like walking on a tightrope. There are three accepted methods of ballast exchange:
- Sequential
- Flow-through
- Dilution
Which method was used on the Cougar Ace? I suppose it is the sequential method.
The Loadmaster has a special RO/RO package but it doesn’t say that there is a ballast exchange module included like other packages have.
Popular are the Ballast Water Management Systems like the
Oceanguard. What is not clear is if this means that no ballast exchange is required.
Rather clear the ballast procedures or failures on the individual ship/ships that had problems were problematic. Of the opinion most were human errors, not double checking behind ( assumed WORKING systems.) IF I were sailing on one of those type vessels, (With the recent history of stability problems and accidents) that would be an utmost priority.
The car carrier Hyundai No. 105 sunk off Batam; Indonesia, after a collision in the Singapore Strait:
Here is some pictures of the hull section on barges after salvage;
I don’t know what rules applied to the Ace at the time but what I did was check the box that no ballast was going to be discharged.
Just keep the ballast on board though the coast-wise.
Bug,aside from collisions, these rigs have a history of known ballast problems. Most, not all ships survive collisions. Some don’t, especially car carriers. I’m sure the posters on here will come up with examples of ships that haven’t had that luck, there are quite few out of the thousands that do remain afloat.
That is what they call Ballast Water Isolation.
I should have said I recall seeing a photo of cars still lashed. Not sure which ship. I was surprised to see it but it is plausible given a small car lashed with four lashing of 2 tons working strength each. Of course there are photos that show cars that did shift.
The question was with regards to the possibility of the cargo shifting on the Golden Ray from a turn induced list. It seem unlikely given that accelerations expected in an ocean crossing are going to be considerably higher.
Here is the Hoegh Osaka
At least a couple cars in this photo have shifted.
What little cargo did shift happened after the ballast problems. IMHO
Are you referring to the AMCO Voyager & Trader? I made one trip to NE as 2nd Mate and it’s the only ship that I’ve ever thrown the job back in getting off before my assignment was completed. They were dangerous ships. They never started cutting corners, they were bare bones to begin with! They got in because they underbid Sea-Land, Lykes, Farrell, and the other companies that bid on government cargo. The following year, Sea-Land underbid AMCO by ALOT (Sea-Land lost money that year on the government cargo) and AMCO couldn’t compete and were basically put out of business! I wasn’t to see them go, they were a disaster waiting to happen.
ss AMCO Trader
Built 1945 by Kaiser, Richmond as the cargo/troopship type C4-S-A1 “GENERAL W.G.HAAN” 12420gt.
Converted to container ship in 1969.
Length 192.9/184.9m, 13489gt 15495dwt.
With the wheelhouse so far forward sailing in bad weather with heavily pitching ship would have been quite a tiring exercise, kind of a roller coaster ride. To keep dry you better have very thick wheelhouse windows…
Lykes built these in the 80’s and APL ran them for quite some time. Known as the Pacific Class and I can speak from experience that once they put them into service on the North Atlantic, it was bad news.
Worse than the ride in heavy seas was the incessant banging of the anchors which made sleep near impossible.