Based on fundamental principles of fluid dynamics, a vessel’s payload capacity primarily depends on its displacement volume—that is, the weight of water displaced by the portion of the hull submerged in water. All other conditions poseidon boat being equal, the longer the hull, the greater the displacement volume, and thus the greater the theoretical payload capacity.
Taking our aluminum landing craft series as an example, this principle is clearly illustrated:
| Model | Length | Beam | Maximum Load Capacity |
|---|---|---|---|
| 5.8m Landing Craft | 5.8 meters | 2.2 meters | 0.6 Ton |
| 7.9m Landing Craft | 7.9 meters | 2.45 meters | 1 Ton |
| 9m Landing Craft | 9 meters | 2.45 meters | 3 Tons |
| 10m Landing Craft | 10 meters | 3 meters | 4 Tons |
| 11m Landing Craft | 11 meters | 4 meters | 6 Tons |
| 12m Landing Craft | 12 meters | 4 meters | 6 Tons |
| 13m Landing Craft | 13 meters | 4 meters | 7 Tons |
| 14m Landing Craft | 14 meters | 5 meters | 10 Tons |
| 15m Landing Craft | 15 meters | 5 meters | 10 Tons |
| 18m Landing Craft | 18 meters | 5 meters | 15 Tons |
| 20m Landing Craft | 20 meters | 5 meters | 20 Tons |
| 21m Landing Craft | 21 meters | 6 meters | 30 Tons |
From 5.8 meters to 21 meters, as length increases, the load capacity steadily rises from 0.6 ton to 30 tons. This positive correlation is a fundamental principle of vessel design and the most commonly used reference metric for purchasers during the initial screening of vessel types.
However, length is not the only determining factor. Beam and draft also have a significant impact on load capacity.
Let’s compare our two 9-meter aluminum landing craft models:
9-meter narrow-body version: Beam 2.45 meters, draft 1.49 meters, load capacity 3 tons
9-meter wide-body version: 3.0 meters wide, 1.49 meters deep, 3.5-ton payload
With the same length, increasing the beam by just 0.55 meters boosts the payload capacity by nearly 17%. This is because a wider hull provides greater deck area and displacement volume.
Now consider the comparison between the 12-meter and 14-meter models: The 14-meter model is 2 meters longer than the 12-meter model, but its load capacity increases from 6 tons to 10 tons—a 70% increase. This is not solely due to the added length; more crucially, the 14-meter model’s beam increases from 4 meters to 5 meters, and its draft increases from 1.69 meters to 2.08 meters. It is the simultaneous expansion of these three dimensions that achieves this significant leap in load capacity.
For purchasers, this means: If you are limited by berth length and can only choose a 12-meter model but require a load capacity of nearly 10 tons, you can achieve this by selecting a wider hull design.
The most significant difference between landing craft and other vessel types lies in their extreme pursuit of shallow draft. Flat-bottomed or shallow V-shaped designs allow aluminum landing craft to navigate in water depths of 0.3–0.7 meters, but this design also involves trade-offs in payload efficiency.
Although deep-V hulls have a deeper draft, they offer a larger underwater volume and, theoretically, a higher load capacity for the same length and width. To achieve shallow-water maneuverability, landing craft must sacrifice some load-carrying efficiency. This is why landing craft of the same length typically have a lower load capacity than conventional cargo ships of comparable dimensions.
Take our 11-meter aluminum landing craft as an example: with a draft of just 0.31 meters, it can carry a payload of 5–6 tons—an outstanding performance among shallow-draft vessels. This balance is achieved through the high-strength properties of marine-grade aluminum—the lightweight hull structure frees up more space for the payload.
No matter how high a vessel’s theoretical load capacity may be, if its structural strength cannot keep pace, it will face risks during actual operation. Can the deck withstand the concentrated load of heavy equipment? Can the hull withstand the impact of beaching? The answers to these questions determine the actual safe load capacity.
Our entire range of aluminum landing craft is constructed using marine-grade aluminum (5083 alloy), with a uniform bottom plate thickness of 6–7 mm and specialized reinforcements at critical stress points. Taking the 14-meter model as an example, its deck’s uniformly distributed load strength has been rigorously calculated to safely support the concentrated load of two trucks. This design with structural redundancy ensures consistency between the theoretical load capacity and the actual usable load capacity.