what is cell guide and Securing guideline for containers on deck and in cargo holds

The cell guides on container ships generally include cell guide in hold and cell guide on deck. Meanwhile, the cell guides in hold include fixed cell guide and removable cell guide.
The fixed cell guides are widely applied onto the container ships carrying 40 feet containers in hold.
The removable ones will be applied while the cell guides in hold need to be adjusted to load different sizes of containers .
Removable cell guides is necessary on the multi-purpose ship and can be removed to load other forms of cargos.
Usage of removable cell guide makes it possible to load 40 feet containers with different height without additional lashing gears. Furthermore, it can improve the efficiency of loading and unloading containers.
The deck cell guides are usually installed on the rear deck to insure the maximum stacking weight due to bigger acceleration and higher tiers on the rear. The height of the cell guide is normal higher than height of  three containers.
Cell guides will improve the stacking weight, transportation capacity of vessel, speed of loading and unloading containers and efficiency.

Containers have very little strength in any direction other than vertically through the corner posts thus it is necessary to provide substantial support to the containers when they are on the ship. Stowage of containers is with their longer dimension fore and aft since the ship motion transmitted to cargo is greater in rolling than pitching and it is therefore prudent to limit any possible cargo movement within the container to the shorter transverse dimension. Also of course when off loading the fore and aft container is more easily received by road or rail transport. Below decks containers are restrained in vertical cell guides which are typically 150 × 150 × 12 angles and they are structurally supported so that any dynamic forces other than purely vertical are transmitted as much as possible through the ships structure and not into the containers. 


The cell guides are not to form an integral part of the ships structure, they are to be so designed that they do not carry the main hull stresses. Where four container corners are adjacent the cell guides may be built into a composite pillar . The clearance between container and cell guide is critical. If it is too small the container will jam, if it is too large when one container lands on the one below the corner posts and castings which accept a maximum eccentricity may not mate. Lloyd’s stipulate a maximum clearance of 25 mm in transverse direction and 40mm in the longitudinal direction. The tolerances are such that the cell guides have to be fitted to an accuracy exceeding normal shipyard practice with the use of jigs to ensure the dimensions are maintained following welding. Lloyd’s require that the cell guide not deviate from its intended line by more than 4 mm in transverse direction and 5mm in longitudinal direction. Lead in devices are fitted at the top of the guides.


Above deck cell guides may also be provided there being several patented arrangements such as the MacGregor-Navire International AB ‘Stackcell’ system. These are not widely used however and many ships carrying containers above deck rely on various deck and hatch sockets with locking and non-locking stackers mating with the standard container corners plus lashings to secure the containers. With locking stackers less lashings are required therefore the more expensive twistlock is often favoured. Deck sockets like the container corner fitting contain the standard ISO hole into which the stackers fit 

Bharatiyulam

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