Page 266 - International safety guide for oil tankers and terminals

INTERNATIONAL SAFETY GUIDE FOR OIL TANKERS AND TERMINALS

14.1.2 Types of Combination Carriers
in pipe tunnels.ึกษาเท่านั้น---
14.1.2.1 Oil/Bulk/Ore (OBO)

The OBO ship is capable of carrying its full deadweight when
carried in top and bottom hopper tanks and some double bottomย์นาวี
trading as an ore carrier with cargoes of heavy ore concentrates.
This type of ship is also designed to carry other types of dry bulk
cargo, such as grain or coal.

On older ships, holds are usually arranged to extend the full
breadth of the ship, with upper and lower hopper tanks and
double bottom tanks. In some cases, holds may have wing tanks.
Oil or dry bulk cargo is carried in the holds. In addition, oil may be
งานห้องสมุด ศูนย์ฝกพาณิช
carried in one or more sets of upper hopper tanks, and where
there are wing tanks, these may also be used. Normally wing
tanks for oily slops are fitted aft of the cargo holds. Ballast may be

tanks designated as segregated ballast tanks. On more modern
ships, side tanks and double bottom tanks used exclusively for
ballast, or as voids, surround the cargo area.

Conventional bulk carrier hatches, normally of the side rolling
---ใช้เพื่อการศ
type, are fitted with a special sealing arrangement.

ึ
Cargo and ballast pipelines are typically installed in a duct keel or

14.1.2.2 Oil/Ore (O/O)
These ships were designed to carry their full deadweight when
trading as tankers and also when carrying heavy ore
concentrates. They were not usually designed to carry light bulk
cargoes. With the advent of double hull requirements for the
carriage of oil, vessels of this type are no longer being built, but
several remain in service.

Heavy ore concentrates are carried only in the centre holds. When
in oil service, cargo may be carried in both centre holds and cargo
wing tanks.

Holds are constructed so as to extend for approximately half of
the total breadth of the ship. Conventional wing tanks incorporate
the main strengthening sections, allowing smooth sides in the
centre holds. Holds are always constructed with double bottom
spaces beneath them. Hatches are generally single piece side
rolling with a sealing arrangement similar to that on OBO ships.

Cargo pipelines are usually installed in the wing tanks, whilst
ballast pipelines are typically installed in the double bottom tanks.
Where cargo pipelines pass through ballast tanks, the possibility
of pollution caused by pipeline failure should be borne in mind.

232 © ICS/OCIMF/IAPH 2006