2.2 General Arrangement Plan

 

Spaces and separations

The general arrangement plan shows the division of a vessel into compartments in cross sections and longitudinal sections.

The compartments are formed by vertical separations (longitudinal and transverse bulkheads) and horizontal separations (decks).

These compartments and spaces serve as storage spaces for cargoes, Stores, equipment, spare parts, liquids, etc., as accommodation spaces for passengers and members of the crew, and as “domestic spaces”, such as galley, pantries, dispensary, etc.

The extreme fore end of the vessel is called stem. The extreme aft end is the stern.

The upper deck, or main deck (a), is often the deck that is exposed to sea and weather.

That is why the main deck is also called the “weather deck”. In fact, it provides a “shelter” for all the contents of the vessel.

The foremost part of the upper deck is called the forecastle (b) - pronounced as [fooksl]). Its bulwark is called the vauxhall. The anchor winches are situated on this deck.

The tween deck (c) is the intermediate deck between upper deck (a) and the inside bottom of the vessel, called tank top (d). The tweendeck divides the vessel into separate holds.

The upper holds and lower holds (e) are the spaces that contain the cargoes.

Spaces for liquid cargoes are called tanks.

Access to a hold can be obtained through hatches. On freighters these hatches must be sufficiently broad for grabs to be lowered into the holds.

The foremost and aftermost spaces of the vessel are the peak tanks (f).

They may serve as storage spaces for ballast water and are capable of “absorbing” a part of the impact- forces that are released in case of a collision.

The anchor chain is stored in the Chain locker(g). It is situated over the fore peak tank.

The upper part of the fore peak tank is called the boatswain’s (or bosurís) locker(h), where ropes, paint and dunnage are kept.

Bulkheads are the vertical separations between holds and spaces.

The fore peak bulkhead and after peak bulkhead (i) are the so-called collision bulkheads. These transverse bulkheads are watertight and prevent the vessel from flooding in case the vessel collides with an other vessel. Collision bulkheads are also fire-retarding or even fireproof.

Apart from transverse bulkheads tankers are also fitted with 2 longitudinal bulkheads that divide the vessel into starboard- and port wing tanks and a centre tank.

The engine room (j) is a watertight machinery space that contains the vessel’s propulsion plant. The steering engine room (k) must also be a watertight compartment and is very often situated over the after peak tank (f).

Due to large stresses that occur under the engine room and peak tanks, additional strengthening are often inserted.

The double bottom (I) provides strength and storage space for fuel, lubricating oil, fresh water, salt (ballast) water and potable water.

To prevent liquids from leaking from one double bottom tank into the other, longitudinal and transverse separations are used between the tanks. These separations, which are in fact empty spaces, are called cofferdams (m).

On the main deck we find the so-called superstructure (n) with the accommodation for the crew and passengers, the messroom, the galley and the pantry.

The navigating bridge contains the wheelhouse with the control station, the chartroom where charts, pilot books and publications are kept, and the radio room.

There are the instruments for navigation, such as the Radar, the log, the echo sounder, the steering compass and repeater compass.

The master compass is usually situated on the monkey island, a small deck or platform over the wheelhouse.

Watch the video clips below.