[QUOTE=Day Sailor;177889]Good, I am glad you think so because it was not meant to be a serious suggestion, just a primer to get people with experience and knowledge to come up with more suitable ideas.[/QUOTE]
As far as I know ocean-going RO/RO don’t have any special safety issues. People seem to be conflating RO/RO ferries with PCC/PCTCs. RO/Ro ferries have had issues. Both the Herald of Free Enterprise and the Estoniasank because of bow doors either being left open or coming off in rough seas. Ocean-going PCC/PCTCs don’t have bow doors.
With regards to PCC/PCTCs (car carriers), the most well known incident was the Cougar Ace which had stability problems during a water ballast exchange. This was crew error and could have just as easily happened to a container ship. They had minimum fuel which is common when the next port is a low-cost bunker port.
It’s been said on this thread that car carriers have a higher center of gravity then other ships. I can’t think why a car carrier would have more problems with GM then a container ship. Issues with GM are usually operational issues, sailing with minimum ballast for lower fuel consumption or to meet draft restrictions. Both theses apply to container ships as well.
The other factor is the nature of the cargo. Carrying non-containerized cargo is going to be inherently higher risk. A box in the cell guides is not going to shift and a box above deck usually goes overboard. If cargo in a PCTC breaks loose by contrast its going to do a lot of damage, heavy cargo could punch a hole in the hull. This has nothing to do with design. It just means the cargo has to be lashed properly.
Issues you don’t see on PCC/PCTC are overweight containers causing stability problems and the entire ship breaking in half.
[QUOTE=Capt. Phoenix;177891]Maybe you should consider not making sarcastic comments like that until you are a known entity. With the name “Day Sailor”, and after the slew of idiotic “cruisers” that came on here playing Monday morning quarterbacking after the El Faro sinking, people are going to assume you are exactly what you named yourself, a day sailor and exactly the type of idiot to make that suggestion and mean it.[/QUOTE]
Did you have a bad day or do you just not have any sense of humour at all?
[QUOTE=Kennebec Captain;177892]As far as I know ocean-going RO/RO don’t have any special safety issues. People seem to be conflating RO/RO ferries with PCC/PCTCs. RO/Ro ferries have had issues. Both the Herald of Free Enterprise and the Estoniasank because of bow doors either being left open or coming off in rough seas. Ocean-going PCC/PCTCs don’t have bow doors.
With regards to PCC/PCTCs (car carriers), the most well known incident was the Cougar Ace which had stability problems during a water ballast exchange. This was crew error and could have just as easily happened to a container ship. They had minimum fuel which is common when the next port is a low-cost bunker port.
It’s been said on this thread that car carriers have a higher center of gravity then other ships. I can’t think why a car carrier would have more problems with GM then a container ship. Issues with GM are usually operational issues, sailing with minimum ballast for lower fuel consumption or to meet draft restrictions. Both theses apply to container ships as well.
The other factor is the nature of the cargo. Carrying non-containerized cargo is going to be inherently higher risk. A box in the cell guides is not going to shift and a box above deck usually goes overboard. If cargo in a PCTC breaks loose by contrast its going to do a lot of damage, heavy cargo could punch a hole in the hull. This has nothing to do with design. It just means the cargo has to be lashed properly.
Issues you don’t see on PCC/PCTC are overweight containers causing stability problems and the entire ship breaking in half.[/QUOTE]
Agree, PCTCs are not the same as Ro/Ro Ferries, (or ROPAX if you want) But they do have in common that they usually are without any watertight separation above main deck level. How water may enter, be it through a leaky ramp, a door left open, or whatever, they quickly loose stability, at least to a large degree of loll.
If that is what happened here I have no way of knowing though, so this is a general observation.
[QUOTE=ombugge;177911]Agree, PCTCs are not the same as Ro/Ro Ferries, (or ROPAX if you want) But they do have in common that they usually are without any watertight separation above main deck level. How water may enter, be it through a leaky ramp, a door left open, or whatever, they quickly loose stability, at least to a large degree of loll.
If that is what happened here I have no way of knowing though, so this is a general observation.[/QUOTE]
If PCTCs are more vunerable to stability or flooding problems then container ships then it should be easy to show statically but I’ve not seen anything. Perhaps some figures could be provided? Otherwise this is just a “those ship look tippy to me” discussion.
In my experience the minimum required GM for a PCTC is about 0.85 - 0.95 meters. Sailing GM is generally one and a half to four times that.
With regards to leaky ramps, the main deck (the deck the stern ramp is on) is 7+ meters above waterline. A lot of water would have to leak in without anyone knowing about it to cause a problem. The ramps are equiped with alarms if they do leak. In general they have to be maintained in good condtion to prevent salt water damage to cargo, not to mention PSC, audits etc.
As far as leaving a door open, conventional ships should not sail with the hatch covers off, the counter-measure is simple, close and dog the hatches before going to sea. Same deal, close and dog the doors before sailing, 100% SOP. You can’t make any ship 100% idiot proof.
Every ship type has their peculiarities, for example how do you put out a on-deck containership fire? On a PCTC 100% of the cargo is protected by fixed systems.
One of the photos of the Marine Express made the list look worse then it is because it was taken when the roll was at it’s most extreme. This video gives a better idea of the list.
Watching that deep slow roll, looks like the righting arm is still positive but it’s on the part of the curve where the righting arm is decreasing.
GZ=righting arm. This is a generic graph. Not specific to this ship.
Likely the ship is not taking on very much water at that angle of list. If there is anything leaking, vents, ramps etc they are just dipping underwater briefly on each deep roll.
Maybe M/S [B]Modern Express[/B] once carried cars and mini-vans, which she was designed to carry. Easy job - just drive 6000 cars aboard and secure/lash them on/to the decks and off we go. Nice, clean, easy job.
However, it seems the vessel was not carrying cars and mini-vans any longer but sawn timber and miscellaneous goods of unknown type and that must have changed the game.
Maybe the cargo was loaded on mafis or or similar and rolled aboard aft (the ship has its own ramp aft) and nobody knew or cared how to secure it on the decks, etc, etc. It is one thing to secure a 1 tons car than a 40 tons mafi with timber to anything. And then some cargo on mafis got loose and shifted to the starboard side pulling other mafis with them.
Result? Permanent heeling 50° starboard while floating on the intact hull but also on the intact weathertight superstructure. And there we are today. The ship is floating but with too much heel.
Hopefully the ship can be towed to some secure place of refuge in lieu of drifting up on rocks being torn apart spilling the fuel oil aboard.
If the ship can reach some secure place of refuge, there are many ways to get her upright again.
Looks like the Modern Drive was in heavy weather and a forklift broke loose. The forklift smashed into the new cars being carried as cargo, gas leaked out and a fire started. The crew thought the fire was in the engine room and cut off the fuel to the main engine.
Unless I missed something the Drive was listing 10 degrees because of shifted cargo.
