What Is an LPG Ship? Understand the Types and Sizes

Liquefied Petroleum Gas (LPG) is a fuel widely used for cooking, heating, and various industrial applications. To ensure safe distribution to different regions, LPG is typically transported using LPG ships.

These specialized vessels are designed to carry large volumes of gas and are equipped with specific storage as well as safety systems that ensure the efficiency of the shipping process.

To find out more about LPG ships, including the types and sizes used in gas transportation, read this article to the end.

What Is an LPG Ship?

An LPG ship is a specialized vessel designed to safely store and transport liquefied petroleum gas. This ship is equipped with tanks and specialized systems that keep the gas in liquid form through specific temperature and pressure controls.

Given the flammable nature of LPG, specialized ships for its distribution are built in accordance with strict international safety standards to ensure safe transport.

Types of LPG Ships

LPG ships are divided into several types, distinguished by the gas storage system within their tanks. These differences relate to how the ships keep the LPG in liquid form during transport. Here are some commonly used types of LPG ships:

1. Fully Pressurized Ships

Fully pressurized ships are the simplest type of LPG carrier among gas carriers. These ships transport LPG at near ambient temperatures but under high pressure to maintain the gas in liquid form.

The tanks used are typically cylindrical or spherical, with a capacity of approximately 3,500-6,000 m³. These ships can withstand pressures of up to approximately 17.5 kg/cm² and temperatures as low as −45 °C.

The tanks are made of carbon steel and classified as Type C pressure vessels, built to withstand pressures above 2 bar. They feature curved walls in cylindrical or spherical shapes and can be installed either vertically or horizontally. Unlike other types of LPG carriers, these vessels are not equipped with specialized cooling systems or insulation. The unloading process is typically carried out using pumps or compressors.

Since they must withstand high pressure, the tanks are quite heavy. This causes the ships to be smaller, and they are typically used to transport LPG or ammonia over relatively short distances.

2. Semi-Pressurized and Semi-Refrigerated Ships

Semi-pressurized and semi-refrigerated LPG tankers use two methods simultaneously to keep the gas in liquid form by pressure and cold temperatures.

The tanks on these ships are generally cylindrical and can carry approximately 5,000 m³ of LPG. The system is designed to withstand pressures of up to approximately 8.5 kg/cm² at a minimum temperature of around −10 °C.

On some ships, cargo capacity can reach approximately 15,000 m³. The tanks are usually made of steel and are spherical or cylindrical. These ships operate at a lower pressure, around 5 kg/cm², but at a much colder temperature, up to approximately −48 °C.

To maintain stable gas conditions, the ship is equipped with systems to regulate gas temperature during both loading and unloading.

In addition to LPG, this type of ship can transport other gases, such as propylene, butadiene, and vinyl chloride.

In fact, if the tanks are made of special materials such as alloy steel or aluminum, these ships can also transport ethylene at much lower temperatures.

The main advantage of these ships lies in their flexible cargo handling system. They can load and unload at storage facilities using either pressure or refrigeration systems, making them commonly used in gas distribution networks across various regions.

3. Fully Refrigerated Ships

Fully refrigerated LPG ships are large-scale LPG vessels featuring more complex technology. These ships use prismatic Type A steel tanks and are equipped with thick insulation to maintain cargo temperatures at extremely low levels.

On these ships, LPG is stored at approximately −50 °C under a low pressure of about 0.28 kg/cm² to keep the gas in liquid form. The cargo storage systems also vary, ranging from separate tanks, double-hulled tanks, tanks integrated into the ship’s structure, to semi-membrane tanks.

The capacity of these ships typically ranges from 20,000 to 100,000 m³, making them commonly used for transporting large volumes of LPG.

Sizes of LPG Ships

In addition to storage systems, LPG ships can also be distinguished by their size or cargo capacity. These capacity differences generally align with the shipping distance and the volume of LPG being transported.

In fact, within certain categories, there are vessels with extremely large capacities that are often referred to as the world’s largest LPG ships because they can carry very high volumes of gas for long-distance trips.

Here are the sizes of LPG ships by cargo capacity.

Handysize: LPG ships with a capacity of approximately 5,000–15,000 cbm. These ships are generally used for short-distance shipments or regional trade.
Medium: LPG ships with a capacity of approximately 15,000–45,000 cbm. This type is used to transport larger quantities of LPG compared to handysize ships.
VLGC (Very Large Gas Carriers): LPG carriers with a capacity of approximately 45,000–85,000 cbm. This type is among the most commonly used for transporting large volumes of LPG, particularly for international or intercontinental trade.

Trust Your Maritime Logistics Solutions to Chandra Daya Investasi

Transporting LPG and chemicals by sea requires specialized vessels designed to ensure cargo safety throughout the journey.

This type of cargo requires tanks as well as pressure and temperature control systems to maintain stable conditions for both gas and liquid until arrival at the destination port.

Chandra Daya Investasi provides marine logistics solutions through PT Chandra Shipping International (CSI), which operates a fleet of specialized vessels for transporting LPG and chemicals.

Currently, the fleet comprises more than 10 vessels with a total capacity of up to 106,650 DWT. These vessels are used to support the shipment of LPG and various chemicals to various regions, while ensuring the distribution process runs smoothly.

This fleet plays a vital role in ensuring the smooth delivery of energy commodities and industrial materials that require special handling during maritime transport.

If your company needs marine shipping solutions, Chandra Daya Investasi, as #YourGrowthPartner through Chandra Shipping International, is ready to provide LPG and chemical carriers designed to support safe distribution.