TYPES OF HATCHES

Hatch covers of ships are designed to be efficient and cost effective, and at the same time should suit the demands of the various types of cargo vessels. The major objective of hatch covers on ships is to prevent the ingress of water into the cargo hold and protect the goods from being damped and damaged. Hatch covers also act as a barrier to the ship’s internal structure by enduring the green water loads in extreme weather, which can damage the internal structure of ship due to corrosion. The various types or hatch covers that are mainly used on board are as follows –

Lifting type

Rolling type

Folding type

LIFTING TYPE: Lift away type hatch covers can be classified into two types –

a) Single panel covers, b) Multi panel covers.

Single panel cover consists of a single cover for each opening, these can be seen mainly on bulk carriers. In case of multi panel covers, a single hold is covered via multiple number of covers, these are most commonly observed in cellular container ships in the case of longitudinal joints, and for multipurpose cargo ship in case of transverse joints.

Stacking cover type: These type of facility are used on ships having relatively smaller hatch cover. It consists of a hydraulically powered lifting crane facility whose purpose is to lift the covers longitudinally and stack it together at one end or over any empty stowage tank. It is relatively cheap and is used mostly in barges.

ROLLING TYPE: Rolling type hatch covers consists of two covers at the end of the hatchway. Wheels are fitted which help in the sliding of the panel either athwartship in case of side rolling or longitudinally in case of end rolling. These type of hatch covers are usually fitted on large ships. Hydraulic rams are required to raise them to rolling position as they are extremely heavy and have very large dimensions

FOLDING TYPE: Folding Type hatch covers consists of two flat topped panels which are operated via hydraulic arms. These may be fitted on both weather deck as well as tween deck. The major advantage of this type of hatch covers is its large size which means less number of panels.