Deadweight Tonnage (DWT)

What is Deadweight Tonnage?

The word ‘ton’ in shipping can denote both weight and capacity. Loaded displacement tonnage is the actual weight of the ship and cargo. Light displacement tonnage is the actual weight of the ship. The difference between the loaded displacement and the light displacement is the weight that the ship can actually carry and is known as the Deadweight Tonnage (DWT).

Bale Capacity and Grain Capacity - what is the difference?

Ship bale and grain capacity measurements are provided by shipyards for dry cargo ships. Ship bale and grain capacities are used for measuring cargo space availability for bulk or non-bulk cargoes. 

Ship bale and grain capacity measurements show the actual volumes available for cargo in numbers. Grain capacity is the space that is available for liquid-type cargo, like bulk grain, which can flow into every corner. Bale capacity is the space that is available for bagged or baled cargoes. Generally, a ship’s bale capacity is about 7–10% less than grain capacity. 

Arrived ship

The Laytime

It is clearly important to determine when laytime commences since this is the key to the division of responsibility for the time spent at the load and/or discharge port. Most charterparties require the owners to serve a notice of readiness at load or discharge port stating that the vessel is ready in all respects for cargo operations, the notice of readiness constitutes the contractual step which is required to trigger the commencement of laytime. Due to this, charterparties usually contain provisions which stipulate when notice of readiness may be contractually served and when laytime commences once notice of readiness has been validly served.

Stowage Factor (SF) is the density of the cargo in the ship’s hold. In the shipping business, Stowage Factor (SF) is a very important piece of information. 

Due to the ship’s cubic capacity, a ship has only a limited volume (space) in her holds. In some cases:

• Light Cargo: the ship’s holds are full before all the ship’s deadweight cargo capacity is utilized 
• Heavy Cargo: full deadweight capacity can be reached with space still available in holds, but that space is unusable

In the shipping business, some historic measurement systems are still in use, for example, variations of the old English system (imperial system) of weights and measures are still frequently used for Stowage Factor (SF) – cubic feet to one ton (ft3/ton). 

Reversible Laytime

In voyage chartering, permitting charterers to add up the laytime allowed for loading and discharging is called Reversible Laytime. In other words, any time saved (or exceeded) at the load port can be carried forward to the discharge port. Depending on the drafting of the relevant clause, charterers may only have a limited period of time for deciding whether to reverse.