How safe are ro-ros?

How safe are

ro-ros?

Because of the publicity surrounding accidents involving passenger

ro-ro ships such as the

Herald of

Free Enterprise, Scandinavian Star

and

Estonia

it is sometimes assumed that this type of ship is

much more dangerous

than others. This is not borne out by statistics. The World Casualty Statistics

for 1994 published by Lloyd's Register of Shipping show that passenger/

ro-

ro cargo loss rate per

thousand ships was 2.3 - the same as the average figure for all ships.

However, when one considers loss of life at sea the picture changes. Between 1989 and

1994, the Lloyd's Register figures show that 4,583 lives were lost in accidents at sea. Of these 1,544

were lost in accidents involving passenger/

ro-

ro cargo ships - exactly one third, even though

ro-ro

ships make up only a small fraction of world merchant marine tonnage. This would seem to indicate

that although passenger

ro-ro ships are involved in an

average number of accidents the

consequences of those accidents are usually far worse.

An important study concerning the safety of

ro-ro

ships (including cargo ships) was

submitted to IMO in 1983 by Norway. The study was compiled by the classification society

det

Norske

Veritas and covered the years 1965-1982. Of 341 casualties during the period, 217 were

defined as serious and 36 resulted in the total loss of the ship.

The study showed that the most common causes of serious casualties were collisions (24%);

machinery damage (17%): grounding (17%); shift of cargo and operational (16%); fire and explosion

(14%). The figures changed significantly when total losses were studied. Here the most common

cause was shift of cargo and operational faults (43%)

; collision (25%) and fire and explosion (18%).

The

dNV study showed that total losses as a result of a collision were much higher for

ro-ros

than for other ships (with only a 9% occurrence). Both collisions and uncontrolled shifts of cargo

more frequently led to serious consequences with

ro-ros.

The paper noted that more than 70% of all

ro-ro total losses due to collision resulted in loss

of lives while 60% of ships reported to have capsized or sunk following a collision did so in less than

ten minutes. Nearly all of the total losses involved ships of less than 110 metres in length.