Section 5 Hatches on exposed decks

5.1.1 This Section applies to small hatchways or access openings in the positions indicated in Figure 4.5.1 Arrangement of doors, sills and hatch coamings.

5.1.2 The number and size of hatchways and other access openings are to be kept to the minimum consistent with the satisfactory operation of the craft.

5.1.3 Hatch covers are to be weathertight when closed, of substantial construction and generally hinged. The means of securing are to be such that weathertightness can be maintained in any sea condition. Details are to be submitted for approval.

5.1.4 Hatch covers may be of steel, aluminium alloy or FRP construction. Where toggles are fitted, their diameter and spacing are to be in accordance with an ISO Standard or equivalent.

5.1.5 Hatches on the weatherdeck in the forward 0,25L _R or to machinery spaces are to be hinged on the forward side.

Figure 4.5.1 Arrangement of doors, sills and hatch coamings

5.2.1 Hatch coamings are to have a height above the deck surface in accordance with Table 4.5.1 Height of hatch coamings. Lower heights may be considered in relation to operational requirements and the nature of the spaces to which access is given.

5.2.2 Flush hatches will be specially considered.

5.2.3 Rope hatches may be accepted with reduced coamings, but generally not less than 380 mm, provided they are well secured and opened only at the Master's discretion. A suitable notice is to be displayed at the hatch.

5.3.1 Hatch covers are to be of equivalent strength to the deck on which they are fitted.

5.3.2 The thickness of the coamings is to be not less than the Rule thickness for the deck in the positions in which they are fitted. Stiffening of the coaming is to be appropriate to its length and height.

5.3.3 The covers are to be adequately stiffened.

5.4.1 Hinges are not to be used as securing devices unless specially considered.

5.4.2 To facilitate a swift and safe means of escape to the lifeboat and life raft embarkation deck, the following provisions apply to overhead hatches fitted along the escape routes addressed by Regulation 13 - Means of escape:

1. Escape hatches and their securing devices are to be of a type which can be opened from both sides;

2. The maximum force needed to open the hatch cover is not to exceed 150 N; and

3. The use of a spring counterbalance, equalising or any other suitable device on the hinge side to reduce the force needed for opening is acceptable.

5.5.1 Where portable plates are required in decks for unshipping machinery, or for other similar reasons, they may be accepted provided they are of equivalent strength to the unpierced deck and are secured by gaskets and closely spaced bolts. The pitch spacing of the bolts will be specially considered depending on the hatch stiffening and support arrangements but should not exceed ten diameters.

5.6.1 Various structural details for hatchways and access openings are given in the LR Guidance Notes for Structural Details.

5.7.1 The weight of hatch covers and any loads carried thereon, together with inertial forces generated by craft motions, are to be effectively transmitted to the craft structure. This may be achieved by continuous structural contact of the hatch cover with the craft structure or by means of defined bearing pads. The bearing pressure will be specially considered depending on the construction material.

5.8.1 The height of the hatch coaming may be subject to additional requirements of the National Authority.

5.9.1 Subject to the agreement of LR exceptions may be given to the requirements of this Section where they interfere with the operation of the craft. Such exceptions will be specially considered.

5.10.1 The items listed in Table 1.7.1 Testing requirements in Chapter 1, are to be hose tested to the satisfaction of the Surveyor.

5.11.1 Standard designs of hatches may be accepted, provided they are designed and manufactured in accordance with the requirements of a recognised National or International Standard which gives reasonable equivalence to the requirements of this Section.

5.11.2 Standard proprietary flush hatches, not exceeding 650 mm x 650 mm clear opening, which are of a type holding a valid Type Approval by LR, may be accepted for under deck access in non-working areas of craft below 24 m in length, L _R, dependent upon the Service Group Notation. Where the hatch type is not type approved, full details, including the material specification, are to be submitted for approval in each case.

5.12.1 Hatchways of novel or unusual design will be specially considered.