IACS: Strength and securing of small hatches on the deck

The International Association of Classification Societies (IACS) has revised the Strength and Securing of Small Hatches on the Exposed Fore Deck.

These revised Unified Requirements (UR S26 Rev5 CLN) were published on 1 May 2023 and will enter into force on 1 July 2024.

General

This UR pertains to small hatches on the exposed fore deck and specifies the required strength and securing devices.

Small hatches in this UR refer to deck hatches providing access to spaces below, with a maximum opening of 2.5 square meters and capable of being tightly sealed against weather or water.

Hatches intended for emergency escape are exempt from certain requirements (5.1 (i) and (ii), 6.3, and 7) stated in this UR.

Quick-acting securing devices, such as central locking mechanisms with one-action wheel handles, must be provided on hatches designed for emergency escape, allowing operation from both sides.

Application

This UR applies to ships contracted for construction on or after January 1, 2004. It is applicable to sea-going vessels with a length of 80 meters or more, where the exposed deck height at the hatch location is less than 0.1L or 22 meters above the summer load waterline, whichever is lower.*

For ships contracted for construction before January 1, 2004, this UR applies solely to hatches on the exposed deck that grant access to spaces forward of the collision bulkhead and the corresponding aft-ward extensions.**

It is relevant for bulk carriers, ore carriers, combination carriers, and general dry cargo ships (excluding container vessels, vehicle carriers, Ro-Ro ships, and woodchip carriers) with a length of 100 meters or more.

The ship length L is defined in UR S2.

This UR does not apply to the Common Structural Rules (CSR) Bulk Carriers and Oil Tankers.

This UR does not apply to small hatches on container ships that comply with UI LL64, except for requirements in clauses 4 and 5.

These hatches are considered non-weathertight, regardless of their actual weather tightness.

However, clause 4 of this UR can be used for determining the scantlings (structural dimensions) of small hatches instead of clause 6 of UI LL64.

Implementation

Ships falling under * (see above) must comply with this UR by the time of delivery.

Ships falling under ** (see above) and contracted for construction before January 1, 2004, must comply based on the following timelines:

Ships reaching 15 years of age or more on January 1, 2004: Compliance by the due date of the first intermediate or special survey after that date.
Ships reaching 10 years of age or more on January 1, 2004: Compliance by the due date of the first special survey after that date.
Ships less than 10 years old on January 1, 2004: Compliance by the date when the ship turns 10 years old.