Moon pool hatch covers MARINE - TTS Group ASA


Moon pool hatch covers MARINE - TTS Group ASA




Moon pool hatch covers

Offshore vessels are often built to comply with specific customer demands.

TTS offers a variety of equipment configurations to help meet these needs.

Moon pool hatch covers are based on standard hatch cover design principles

with special attention to slamming forces and bottom sea pressure. Tailor made

solutions are available upon request, depending on ship design and purpose.



The drawings show some of the

various moon pool cover designs

installed onboard different

offshore vessels.

Bottom moon pool covers

A commonly used type is the

side hinged two-section cover

shown in Figure 2. In open

position the two sections

ensure a flat moon pool surface

free from obstructions. As

an alternative, a side hinged

foldable cover can be installed

stowing in one of the sides.

Figure 1 shows a top moon

pool cover, and the principle

is identical for a bottom cover.

Both types are hydraulically

operated and cleated and the

movement controlled by guides

fitted at each side of the cover.

Figure 4 shows a lifting and

sliding cover, operated by

hydraulic cylinders and by rack

and pinion.

Fig. 2




Cover in open and

secured position

Fig. 3

Fig. 4

Top moon pool covers

Top covers are normally fitted

whether or not bottom covers are

installed. An inexpensive solution

is to install a lift-away cover

operated by a crane, secured by

manual cleats or by a hydraulic

system fitted into the coaming.

Where the moon pool is placed

in a hangar area several other

alternatives may be considered.

Side hinged covers in one or two

sections can be hydraulically

operated and cleated (Figure 1).

Sliding covers are usually installed

where there is limited height. With

this solution (Figure 3), cargo

does not need to be removed

when operating the hatch cover.

A much used solution is similar

to that shown in Figure 2 as a

bottom hatch cover, but this

time located at the top of the

moon pool. Two side hinged

panels open downward into a

recess in the moon pool trunk,

thus avoiding snagging any

equipment in the hangar.

Fig. 1

Cleating Cover in closed position




Cover in open and

secured position

Hydraulic cylinder


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