PRS: Structural Rules for Bulk Carriers and Oil Tankers

The Polish Register of Shipping (PRS) has published the updated Common Structural Rules for Bulk Carriers and Oil Tankers.

This International Association of Classification Societies (IACS) document was published on 29 May 2023 and will enter into force on 1 July 2023.

These Rules supersede the Common Structural Rules for Bulk Carriers and Oil Tankers, January 2022.

These Common Structural Rules consist of two parts. Part One provides requirements common to both Double Hull Oil Tankers and Bulk Carriers and Part Two provides additional requirements applied to either Double Hull Oil Tankers or Bulk Carriers.

The following ships are subject to these Rules:

a) Bulk carriers and double hull oil tankers;
b) Self-propelled ships with unrestricted navigation;
c) Ships contracted for construction on or after 1st July 2015.

These Rules are applicable to ships that are constructed of welded steel structures and comprised of stiffened plate panels.

The ship's structure should be longitudinally or transversely framed, including full transverse bulkheads and intermediate web frames.

According to the rules, the typical structural arrangements of covered ships should include a double bottom, complying with relevant statutory requirements, and an engine room situated aft of the cargo tank/hold region.

The hull structures of bulk carriers, whether single side skin or double side skin, with a freeboard length (LLL) of 90 m or more, fall under the scope of these Rules.

Bulk carriers are generally built with a single deck, double bottom, hopper side tanks, and topside tanks, and they are primarily intended for the transportation of dry bulk cargoes. Figure 1 illustrates the typical arrangements of bulk carriers.

Hybrid bulk carriers, which feature at least one cargo hold constructed with a hopper tank and topside tank, as shown in Figure 1, and other cargo holds without such tanks, as depicted in Figure 2, must adhere to the strength criteria defined in these Rules.

The following ship types are exempt from these Rules: ore carriers, combination carriers, woodchip carriers, cement, fly ash, and sugar carriers, provided that cargo handling does not involve grabs heavier than 10 tons, power shovels, or other means that may damage the cargo hold structure.

Additionally, ships with inner bottom construction designed for self-unloading are also not subject to these Rules.