Following the sinking of the car carrying RO-RO (roll on-roll off) “BALTIC ACE” in only 15 minutes following a collision with what appears to have been a smaller ship, gCaptain is raising questions regarding the safety of the type. Of the crew of 24, 13 were rescued, five bodies were recovered, and six are missing and presumed dead.
Issues they see with regard to RO-ROs are that the type tends to sink faster and more easily than other types of ships, and that their design may also make it more difficult for the crew to abandon ship.
In the interest of efficient loading and unloading RO-ROs tend to have few water tight bulkheads. They may have large openings in the hull, close to the waterline, covered by equally large hatches, some of which also serve as ramps. Their stability may be compromised by cargo that can shift easily. Because of their high sides, lifeboats are usually positioned high above the water, making lowering and embarkation more difficult.
gCaptain does acknowledge.
“While many experts agree that RoRo’s are dangerous, in 2004, more than 1.3 billion passengers, 188 million cars, 856,000 buses and 28.7 million trailers were carried on 5.9 million crossings globally and non-passenger carrying RoRo’s, like the Baltic Ace, have a similarly impressive safety record in recent years.”
An index of gCaptain’s coverage of the incident here.
Chuck Hill's CG Blog 
while Baltic Ace is generically a Ro/Ro, it is specifically a PCTC Pure Car Truck Carrier. I do NOT think the records fo Ro/Ros overall are a bad as for PCTC?
The cargo ramps are watertight and in a location where damage due to collision is unlikely. I’d be more concerned about the side structures.
However, I agree with you regarding the lifeboats. How about making free-fall lifeboats mandatory for this kind of vessels as well? Quite many ro-ro’s and car carriers already have them.
I agree the freefall lifeboats make a lot of sense.
On the other hand, the hull openings have been a weak point, particularly bow doors. Looking at MS Herald of Free Enterprise (1987), MS Estonia (1994) here http://gcaptain.com/extraordinary-modern-shipwrecks/
Serious impacts to the hull are likely to tweak water-tight closures in the hull and render them non-tight.
Herald of Free Enterprise sank because the doors were left open on purpose. Estonia’s bow visor was of bad design that has not been used since. I have never heard of issues with “traditional” vertical stern doors/ramps – they seem to have a pretty good good track record.
Baltic Ace had whopping ~1000 mm double sides. No wonder she capsized and sank so quickly.
One meter between the double sides? Most ships have not been double hulled, but compartmentation should have permitted the ship to remain afloat even after partial flooding.
Although some idiots still build single-skin bulk carriers, most ships in these days regardless of type have either a double hull or side ballast/void tanks under the main (strength) deck. Often it is mandated by the rules.
In case of ro-ro ships, the problem is the continuous car deck, which prevents compartmentalization due to the lack of transverse bulkheads. For that reason, ro-ro ships should have large side tanks to prevent flooding in case of side collision. Ro-pax ships often have a longitudinal bulkhead B/5 from the side. This ship had void tanks on both sides of the lower cargo deck, but they were only 1,300 mm wide (corrected value from technical data), meaning that even a minor collision would penetrate both the outer shell as well as the longitudinal bulkhead. I call that bad design.
I agree. The bulbous bow of the Corvous J made an excellent ram. nearly all the energy applied by the collision was below the waterline.
http://gcaptain.com/corvus-j-containership-damage-photos/
The idea of longitudinal bulkheads is similar to the torpedo bulkhead schemes that used to be used on warships. To take advantage of the greater depth of protection a longitudinal bulkhead, as opposed to a double hull, and prevent loss of stability they included the capability to counterflood spaces on the opposite side. The length of the voids was also interrupted frequently by transverse bulkheads.