LR redefines rules for high speed aluminium catamarans

26 October 2017

LR has updated its Special Service Craft (SSC) Rules and Regulations with a specific focus on aluminium catamaran designs and other high speed craft. The new rules allow for greater design freedom and increased flexibility, improving LR’s approach to these weight critical designs.

By reducing prescriptive arrangements, the new rules are tailored for these specialist vessel types, offering flexibility in requirements tailored to operating areas and a greater scope for special consideration of design arrangements. LR will work with its clients to co-create bespoke design solutions.

This rule update was driven by the industry need to safely and rapidly exploit the benefits offered by developing technologies. LR conducted a series of weight studies that have validated improved structural efficiency for these vessel types. The new rules will support innovation in the sector by establishing requirements for which compliance can be demonstrated through the application of risk-based assessment techniques.

Joanna Mycroft, LR Senior Specialist, commented: “Having just completed the structural approval of vessels for Harbour Ferries using LR’s new SSC rules, I have been able to see how well they fit this format and the benefits that they bring to designers. The rules create a flexible approach to the design that provides a solution to fit a wide range of different requirements.

“The new rules provide lighter, faster vessels, with much more scope for adapting the rules to each design individually. This really puts us ahead in the market and provides rules that will be applicable for many years to come.”

For multi-hull vessels a number of arrangement criteria have been updated and prescriptive requirements have been removed. Examples of these include requirements for bridging structure bulkheads and members typically used for dry-dockings, including centreline girders.

Minimum thickness requirements have also been updated based on service experience. In areas that are well protected from occasional loads, these requirements may be less relevant. These changes allow designers to exercise an engineering approach to improving structural efficiency. 

The minimum design pressure for glazing has been reviewed in terms of the minimum load formulation to be applied to vessel glazing. This reduction in design pressure requirements is expected to provide weight savings.