LOADING CARGO ONBOARD HEAVY LIFT SHIPS
There are special ships to transport heavy objects such as train engines, oil rigs, small damaged ships, SPMs, Generators, turbines, reactors, boilers, towers, locomotives, satellites, military tanks etc.
When loading cargo, careful attention must be paid to the weight of the cargo. The load density to be calculated & it should be never exceeding. The maximum weight which can be loaded safely in an Area of 1 square meter without causing any damages to that area is known as the load density. If the load density is insufficient place dunnage to increase the area thus reduces the pressure acting on unit area.
If spreaders or heavy pallets are used in heaving up the cargo, take their weight into account as well.
Special attention must be given for lashings. Ensure securing points are strong enough for lashing the cargo by referring in securing manual.
Calculate the GM for critical stage just after the weight is taken by Crane/ Derrick & after loading. Particular attention should be given for “Lateral Drag”. While the cargo is lifted it tends to move in a horizontal direction this is known as Lateral drag. The lateral drag is away from the ship while loading & towards the ship while discharging the cargo.The vessel to be upright at all times. All loose items to be secured before lifting the cargo.
If the heavy lift ship is semi submerging type the vessel itself will submerge & take the floating cargo onboard.
Free surface effect to be reduced. The ballast tanks to be either full or empty.