What is meaning of Deck cargo on ships ?

Deck cargoes refers to items or commodities carried on the weather-deck and hatch covers of a ship and thereon exposed to sun, wind, rain, snow, ice and sea, so that the packaging must be fully resistant to, or the commodities themselves not be denatured by, such exposure.

Deck cargoes, because of their very location and the means by which they are secured, will be subjected to velocity and acceleration stresses greater, in most instances, than cargo stowed below decks.

More often than not, there is no shell plating, framing or bulkhead to stow against and secure to, and isolated structures may offer little protection against the force of waves shipped over decks and hatches. Even in Ro-Ro vessels, many areas above the actual ‘Hold’ space can reasonably be considered as “on deck” even though not fully exposed to the onslaught of wind and sea.

Deck cargo shall be so distributed and stowed –

 As to avoid excessive loading having regard to the strength of the deck and integral supporting structure of the ship; as to ensure that the ship will retain adequate stability at all stages of the voyage having regard in particular to –

• The vertical distribution of the deck cargo;
• Wind moments which may normally be expected on the voyage;
• Losses of weight in the ship, including in particular those due to the consumption of fuel and stores; and
• Possible increases of weight of the ship or deck cargo, including in particular those due to the absorption of water and to icing; as not to impair the weather tight or watertight integrity of any part of the ship or its fittings or appliances, and as to ensure the proper protection of ventilators and air pipes; that its height above the deck or any other part of the ship on which it stands will not interfere with the navigation or working of the ship; that it will not interfere with or obstruct access to the ship’s steering arrangements, including emergency steering arrangements; that it will not interfere with or obstruct safe and efficient access by the crew to or between their quarters and any machinery space or other part of the ship used in the working of the ship, and will not in particular obstruct any opening giving access to those positions or impede its being readily secured weather tight.