Piggy-Back Hatch Cover

The piggy-back hatch cover is also known as the lift-roll hatch cover. When deck space is tight, the piggy-back hatch cover provides a compact, efficient design for situations where folding hatch covers and side-shifting hatch covers cannot be stored.

The piggy-back hatch cover comprises two cover plates, one of which is a power cover plate, the outside is equipped with a roller, and the low jacking oil cylinder is arranged under the roller, and the roller can be rolled on the track after it is lifted; the outside of the other non-powered cover plate is equipped with an overhang arm, and four upright high tops and cylinders are mounted along the hatch circumference below the overhang arm. When the non-powered cover plate is raised to a sufficient height by the cylinder, the power cover plate is rolled under it, and then the non-powered cover plate is lowered, and the power cover plate can be carried on the non-powered cover plate, and the two pieces are rolled together to the collection position.

The system can be applied to either a pair of cargo hold openings or two panels on a cargo hold opening. If the number of covers exceeds two, the system is called a "stacked hatch cover".

Piggy-Back hatch cover

Folding Hatch Cover

The folding hatch cover is generally composed of two panels, called a single pair folding. The cover plates are connected by hinges, and rollers are arranged on both sides near the hatch end. During opening, the active cover rotates around the end hinge shaft and pulls the roller of the driven cover onto the track until the two cover plates are folded together and stored outside the hatch end and above the panel of the hatch coiling plate.

A folding type consisting of two or more pairs of cover plates is called a multi-pair folding hatchcover. Each cover plate is connected with a drag eye plate. When opened, fold one pair at a time.

The folding cover plate has good strength, is not easy to damage, and is suitable for loading all kinds of deck cargo; No compacting device is required for the transverse joint, no jacking device is required for the roller, and the operation is simple and reliable. The collection length and height are adaptable, suitable for both open deck and middle deck; Therefore, it is widely used in general dry cargo ships, multi-purpose ships, refrigerated ships, wood carriers and small and medium-sized bulk carriers. According to the length of the hatch and the position of the collection, the number of cover plates and the direction of collection are determined. A single pair of folding is preferred, and for hatches with sufficient collection status at only one end, or longer hatches with more cover blocks, multiple pairs of folding can be used.

Folding Hatch Cover

Side-Rolling Hatch Cover

The side-rolling hatch cover is usually composed of one or two cover plates, and the hatch cover is provided with a rolling device, a jacking device, a sealing device, a connecting device, a limiting device and a driving device. The cover plate is rolled horizontally and stored in the outer guide frame on the side of the hatch. The joint between the cover plates is arranged longitudinally, and the left and right cover plates are opened to both sides respectively.

The side-rolling hatch cover is a low-collection hatch cover, which saves effort to open and is suitable for larger and heavier cover plates; There needs to be enough space to store the cover plate next to the hatch, so it is widely used in 40000~150000t class large bulk carriers, mining and grain dual-purpose ships and mining and grain oil triple-purpose ships with the hatch width accounting for less than 50% of the ship width. The hatch cover has the advantages of fewer cover blocks, simple structure, reliable opening and closing, convenient operation and easy maintenance.

• Power cover plate drive mode

• Long chain drive
  

Driven by circulating long chain, low speed and high torque hydraulic motor, both sides of the hatchcover are equipped with drive chains, which is the same as the single pull and side shift hatchcover. Long chains can also be provided only on one side of the hatch.

• Fixed chain drive
  

A mini electric winch is installed in the cover plate, and a traction device composed of a driving sprocket and two driven sprockets drives the cover plate along a fixed chain laid on the hatch coiling panel; The electric winch is symmetrical and set in pairs.

• Built-in drive device
  

The cover plate is equipped with a motor and a reduction gear box to drive the roller directly. Each power cover plate is provided with two or four sets of driving devices, which can be used for heavy cover plates, as shown in the figure.

• Gear and rack drive
  

The drive mechanism is the same as that of the sideshift hatch cover.

Side-Rolling Hatch Cover

Lift-Away Hatch Cover

There is no connecting device or transmission device between each cover of the lift-away hatch cover. The cover plate is equipped with lifting eye plate or container lifting base, and the cover plate is lifted directly from the ship or shore cargo lifting equipment or container hanger. The cover can be stacked on the adjacent hatch cover roof, or stacked on the dock. The hatchcover is suitable for both open decks and middle decks. For example, the steel hatch covers on open decks are still covered with traditional wooden wedges, pressed flat steel, ropes and canvas to achieve a weathertight dropaway hatch cover, also known as a box hatch cover in some codes.

The lift hatch cover is simple and reliable, and does not require a drive device, so the cost is cheap and the maintenance is convenient. Because the number of cover blocks is not limited, it is suitable for various lengths of hatches, and is also suitable for various deck hatches, so it is more used in the open deck of all container ships, the middle deck of multi-purpose ships and the long hatch hatches. It is also often combined with a single pull or folding type as a combined hatch cover for a long hatch. The hatch cover is not suitable for bulk carriers without cargo lifting equipment. In a full container ship, although there is no cargo lifting equipment, the cover plate can be suspended by a special container hanger on the dock, and it is very convenient to lift off a cover plate as if lifting off a container.

Lift-Away Hatch Cover

Hydraulic Pivoting Hatch Cover

The advantage of the hydraulic pivoting hatch cover is that it maximizes the available deck space. The main condition of whether to choose a hydraulic pivoting hatch cover is the size of the opening of the hatchway and the space required for the cover collection. The maximum length of the hydraulic pivoting hatch cover is 45 feet. When multiple covers are not required, or the deck storage space is short and vertical, most will choose to use hinged tip-over hatches.

Hydraulic pivoting hatch covers are mostly used on container ships. Because of the vertical storage position occupied by hydraulic pivoting hatch covers, the size of other deck machinery such as cranes must be carefully considered when designing hydraulic pivoting hatch cover.

Hydraulic Pivoting Hatch Cover

This is the end of the introduction of marine hatche covers, thank you for your browsing, I hope you have found the answer you are looking for. If you have other needs or questions about marine covers, please feel free to contact us or visit our Marine Covers homepage!