General cargo ships have one to four holds, often with a tween deck that splits each hold into a lower hold and a space above it. Cargo is loaded as separate units: pallets, steel bundles, coils, bags, crates, machinery and even vehicles. Many ships carry their own cranes or derricks so they can work ports with limited facilities.
In Indonesian waters, inter-island general cargo ships are the backbone of cement, steel, project material and consumer goods distribution to small ports. Rotations are often multi-port, so cargo must be arranged so each port can discharge without moving cargo for another port.
The planner’s main challenge is mixing dense and voluminous cargo. Steel with a low stowage factor reaches the weight limit before the hold is full, while light cargo fills the volume before the ship reaches her marks. A good plan mixes both while keeping tank top and hatch cover loads, GM and trim in check.
Typical sizes & characteristics
| Parameter | Typical range |
|---|---|
| Typical size | Inter-island ~1,000–8,000 DWT; ocean-going general cargo/MPP ~5,000–20,000 DWT |
| Holds | 1–4 holds, often with fixed or pontoon tween decks |
| Cranes/derricks | Usually ~20–60 t SWL each; check certificates and outreach charts |
| Tank top strength | Per hold from the ship’s plans; far higher than the limit on hatch covers |
| Cargo stowage factor | From ~0.3 m³/t (steel) to > 3 m³/t (light, bulky cargo) |
| Typical draft | Inter-island ships ~3–7 m |
Typical ranges for the vessel class, not data for any specific ship. For planning, use your vessel’s stability booklet and capacity plan.
Cargo spaces & how they are modelled
Lower hold
The largest space, for heavy and dense cargo. Modelled as a scaled 2D plan with tank top load limits per m² and clear height.
Tween deck
An intermediate deck for lighter cargo or cargo to be discharged first. Its load limit is lower than the tank top and is checked separately.
Weather deck and hatch covers
Deck cargo such as vehicles, pipes or large crates loads the hatch covers. Hatch cover limits and lashing needs are recorded per panel.
Crane working area
Crane outreach and SWL define which parts of a hold can be reached safely, especially for heavy pieces in hold corners.
General stowage rules
Distributed and point loads
Heavy cargo sits on dunnage so the load spreads and stays within the tank top t/m² limit. Point loads from machinery feet or coils need special attention.
Discharge order
Cargo for the first port goes where it is easiest to reach, in the tween deck or upper part of the hold, never under cargo for other ports.
Separation and compatibility
Cargo that can damage each other, such as wet cargo next to moisture-sensitive goods or odorous cargo next to foodstuffs, is separated.
Securing per CSS Code
Cargo is secured with lashings, chocks and dunnage per the ship’s Cargo Securing Manual, allowing for transverse forces when rolling.
Stability and trim
The mix of dense cargo low and light cargo high is controlled so GM is neither too small nor too large, with a slight trim by the stern on departure.
Common mistakes & risks
- Tank top limits exceeded because heavy cargo was landed without enough dunnage.
- First-port cargo buried under cargo for later ports.
- Cargo shifting while rolling because chocks and lashings were inadequate.
- Cargo damage from hold condensation (ship sweat or cargo sweat).
- Deck cargo exceeding hatch cover load limits.
- Cranes worked close to SWL without allowing for outreach and the ship’s heel.
Frequently asked questions
What is broken stowage?
Broken stowage is hold volume left unused because of cargo shape, dunnage or gaps around structure. It varies by cargo type and is allowed for when estimating hold capacity.
How do I choose between tank top and tween deck for heavy cargo?
Heavy cargo normally goes in the lower hold because the tank top is stronger and KG is lower. The tween deck is used when cargo must be discharged first and its load stays below the tween deck limit.
Does STOWAGE.ID support general cargo ships?
Yes, General Cargo and Breakbulk are in the first wave together with Barge and LCT. Its stability results are shore-side planning; the class-approved onboard loading computer and stability booklet remain the official reference.
Shore-side planning & decision support. The class-approved onboard loading computer remains the official reference.