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GENERAL ARRANGEMENT (GA)

INTRODUCTION:The general arrangement (GA) drawing is a drawing that shown arrangement of

all spaces on the ship. The process of design about general arrangement is related to

the function of ship that must follow its rules and regulation that has been decided by theclassification board. The general arrangement must be economical, fulfill the ownersrequirement demand and logical.The important information which should be prepared to complete the task are shownbelow:

1. Lines plane drawing.2. Curve and hydrostatic data.3. Rules and regulation4. Reference ships.

MEHTOD TO DRAW THE GENERAL ARRANGEMENT

Information need to do the task.The information needed to drawing the general arrangements are:a) Lines plan drawing.b) Curve and hydrostatic data.c) Rules and regulations, the GermanischerLloydwere used.d) Example of basis general arrangement of pull tugboat.

Complement and the rank.-Base on the owners requirements. ,-ExampleThe rank and their duty are shown below:

One captain: Leader of the ship, giving order for other officer and crews,

navigator and pilot. One engineer: Responsible for machinery on board of ship.

Two crews: As the cook, cleaner, tie towing winches and pilot.- For merchant cargo, container and tanker (other than passenger carrier) the

number of crew is normally not more than 12. However for passengerliner/carrier the number and class of passenger need to be determined inorder to design the cabin and other related compartments.

Determination of frame spacing, watertight bulkhead and double bottom.a) Frame spacing.b) Watertight subdivision, bulkheadc) Double bottom

- These have to be determined based on rules and regulations. The position ofbulkhead must be adjusted to the nearest transverse or frame position (afterdetermining frame spacing).

- Most ships (esp. large ships) must be fitted with double bottom mainly forstorage of grease oil, drainage etc and for safety when grounding. The heightof double bottom can either be proportionally deduced from basis ship orcalculated based on rules and regulations.

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Determination of cargo compartments- Once the allowable bulkheads positions have been determined, the cargo

compartments can be easily determined. For passenger vessel, several decksabove main deck may be necessary to accommodate the number ofpassengers. For container, no extra deck is required above main deck, but thecontainers can be stacked above main deck. For vehicle carrier and RO-RO,

twin deck may be necessary.

Determination engine room spaces and other related machineries- Engine and propulsion room can be determined using empirical formula based

on the required power. Other machinery may be determined based on thetype of system used on board and ship function. For preliminary design, thisdata can be referred from basis ship of similar type and size.

Determination of tanks (volume and dimension)- Apart from fuel, ship must also carry fresh water, ballast water, grease oil etc.

The size of fuel and fresh water tanks shall be determined based on

consumption (fuel and water) and endurance of the ship.- Fuel consumption can be estimated based on power and engine size. The

total fuel carries for single operation of ship based on endurance and fuelconsumption.

- For fresh water volume can either be determined based on standards or basiccalculation. Allowance shall be included in the calculation for emergencysituation.

The fresh water carries for single operation base on total crew andduration of the voyages.

For a single personnel the amount of fresh water is about 0.16 ton perday (the figure might be varies depend on many factors).

- Ballast water tanks are normally fitted at aft or forward peak and wing of theship mainly for stability and trim purposes.

Step 7: Accommodations space, access area and safety requirement.- These include cabins, galley, mess /dining area, toilets, recreational areas etc.

The area shall be determined based on the number of crews and passengerand their rank/class. Guideline for the suitable area or volume can be referredfrom related references. Analysis on path way/access and safety route is alsoessential.

a) Accommodation spaces.Divide into subdivision such as mess room, galley and crew or officerroom.

b) Access areaThe access areas are divided into two sections which one is primalaccess area (inner ship) and emergency access area (outer ship).

c) Safety requirementExample: the safety requirement such as fire fighting system, safetyraft and salvaging.

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Bridge/ wheelhouse.- Bridge spaces and equipment: The Bridge situated at the top of the designed

workboat. The bridge may contains navigation room, pilothouse, radio roomand chart room. At preliminary design stage, these areas can be determinedbased on the basis or reference ship.

Others item.Example:

a) Mooring equipment.-For mooring, the equipment are mooring winches, bollards, ropes andhawses.

b) Anchoring equipment.-For anchoring, the equipment are anchor, anchor winches (also use samemooring winches), chain cable and chain locker.