Section: 11 CARGO OPERATIONS - Univan

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FLEET OPERATION MANUAL Date 01.01.2005
11.2 Major safety Concerns
MAJOR SAFETY CONCERN
SECTION 11.2
Ro-Ro Cargo Carriers have their own peculiarities, and these special characteristics are very
different from the other vessels. This makes these Ro-Ro Cargo Carriers as very special vessels.
And we need to understand what these peculiarities are and how they affect the vessel operation.
Hereunder we are giving you a list of these special characteristics, so that you keep bringing
them into your consideration while operating this kind of vessels:
11.2.1 External ramps
The vessels are fitted with external ramps. These are the large openings to give access
to cargo compartment for the purpose that roll on and off cargo may easily be loaded.
Imagine now on a dry bulk carrier we have detailed procedures and precautions to avoid
any ingress of water from cargo hatches.
Remember now those hatches are horizontal and on weather deck, and in case of Ro-Ro
Cargo Carriers ramps are vertical and on the ship side.
We leave it to your imagination how many times more careful you should be while
operating external ramps for water tightness.
11.2.2 Connectivity of all the cargo compartments
For the accessibility of all the cargo spaces they should be approachable to external
ramps through the adjoining cargo spaces. Well, this means, the complete cargo area is
exposed to seawater ingress, in the event of flooding of any one part of cargo space.
Also the fire may spread to all adjoining cargo spaces as all the cargo space are
interconnected, if fire doors are not closed.
Vessel is divided into individual fire zones, and these fire zones can be isolated from
each other by gas tight doors.
But what if the fire breaks out during the cargo operation when the these gas tight doors
are open for accessibility of cargo, and now these gas tight doors can not be reached for
closing.
This is also unlike of other ships where one cargo compartment does not have access
from the other compartments.
11.2.3 Large cargo volume with respect to deadweight assigned
This is also an inherent characteristic of a car carrier. Before understanding what is so
important with this characteristic, please go through a vessel’s particulars of a 2528 unit
Ro-Ro Cargo Carriers, which are given hereunder.
Lightship = 7383 MT
Deadweight = 9358 MT
Gross Registered Tonnage = 27013
Length between perpendiculars = 148M
Breadth molded = 27.8 M
Summer draft = 9.358M
Engine Power= 9450 SHP
These figures may surprise some of you, who have not been working on this kind of ship.
On an average on other cargo vessels light ship is about 25% of summer deadweight and
GRT is about 45% of summer deadweight.
And in the case of PCC vessels, we have lightship almost equal to deadweight and GRT
is 3 times the deadweight.
So this is clear these vessels that these vessels have low deadweight assigned to their
lightship. We can also say that they have low volume below the summer draft.
In other words they have low under water volumes even in loaded conditions, if we
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