The following provides a brief overview of some of the most significant changes that have taken place in the Rules for Classification of Ships in the January 2006 issue.
IACS Common Structural Rules
A new volume 4 and 5, containing Pt.8 Ch.1 and Ch.2 respectively, has been introduced to cover the new IACS common structural rules. Ch.1 contains ‘Common Structural Rules for Double Hull Oil Tankers with Length 150 metres and above’ while Ch.2 contains ‘Common Structural Rules for Bulk Carriers with Length 90 metres and above’.
Operation in cold climate
The existing class notations ICE-xx, DEICE and DAT(–x°C) give a fragmented picture with respect to operation in cold climate, and do not cover all relevant concerns related to a suitable trade in such waters.
The new class notation WINTERISED encompasses the requirements in the above notations and with additional requirements intending to complete the fit-for-purpose picture:
- WINTERISED (design temp.)
The information within the brackets states the design temperature in °C.
Application: Ships intended for cold-climate trading over longer periods. - WINTERISED ARCTIC (design temp.)
The information within the brackets states the design temperature in °C.
Application: Similar to WINTERISED (design temp.), but with additional requirements to limit the possible negative environmental impact of ship traffic in the vulnerable arctic areas.
Emergency propulsion features
New rules for ‘Emergency Propulsion’ have been introduced to meet a market demand for additional propulsion safety features. The requirements reflect some local legislation with respect to requirements for trading in certain sea areas with a cargo which, when spilled, pose a threat to the environment.
The feature has the designated class notation grades; namely EP-1(a%)(+),
EP-2(a%)(+) and EP-3(a%)(+):
- EP-1
Example of arrangement: Main and Emergency Propulsion is provided by a common propulsion system with propulsion Machinery Redundancy, e.g.:
2 prime movers connected to common gear, 1 shaft line and 1 rudder, alternatively double winded electrical motor (armature and excitation), and partly separate auxiliary systems for each prime mover or winding, where
2 prime movers or 2 windings in operation constitute the main propulsion system, and 1 in operation constitute the Emergency propulsion system. - EP-2
Example of arrangement: Main and Emergency Propulsion is provided by separate systems, e.g.:
1 prime mover, 1 shaft line and 1 rudder providing the main propulsion system, and 1 separate azimuth or pod-thruster providing the Emergency propulsion system, and separate auxiliary systems for each of the propulsion systems. - EP-3
Example of arrangement: Main and Emergency Propulsion is provided by separate systems as for EP-2, in addition the prime mover and thruster and their auxiliaries are separated by watertight A60 bulkheads.
A suffix (a%) is added where a% is the percentage of the emergency propulsion power relative to the main propulsion power.
A suffix (+) is added when the system has a proven holding capability.
The design shall follow the ‘single failure concept’, except for components accepted as common components in the system.
When a failure has occurred, the remaining power shall at least be capable of keeping the vessel:
a) in position at Beaufort 8 weather with corresponding wave conditions, or
b) maintaining a speed of not less than seven knots, except for single failures in acceptable common components.
Rotating machinery
Pt. 4 Ch.2, Ch.3, Ch.4 and Ch.5 have been amended to reflect new IACS requirements. Further the booklets have been adjusted to align with current safety thinking and system knowledge.
Date: 2006-03-13