Decade long, and on-going, research programme has developed a clearer understanding of the forces imposed on ship structures
Lloyd’s Register’s updated container ship rules came into effect in July 2014 and these new rules are supported by Lloyd’s Register ShipRight Procedures covering whipping and springing analysis. Following the ShipRight Procedure will enable the granting of new Lloyd’s Register class notations ShipRight WDA – Whipping design assessment procedure, and ShipRight FDA (SPR) – Springing fatigue design assessment procedure, to enhance the response of ships’ structures that are subject to springing and whipping at sea.
While the basic rules that underpin containership structural strength are well established, as ship sizes increase, new challenges have emerged making continued research into the implications essential.
Modern container ships have very large deck openings, long, fine hull forms, a large bow flare (the projection of the forward deck outwards above the waterline) and operate at fairly high operational speeds (roughly 18 knots or over). They must, of course, meet the structural strength and fatigue requirements imposed by all sea conditions.
Lloyd’s Register’s research on large container ships has been ongoing over the past decade and includes a full-scale measurement programme conducted over five years on a large container ship. This research has helped to identify the challenges faced by builders and operators of such ships and ensure that the ships’ structures are properly designed and remain within acceptable limits throughout their operational lives. More generally, Lloyd Register’s research and operational experience has provided the tools to properly and effectively assess the forces involved in large containership operation and thereby provide the appropriate rules and guidance.
New designs approved by LR have progressively benefited from the output of this research and development.
Lloyd’s Register’s Marine Director, Tom Boardley, commented: "Ship safety is our main role as a classification society. You can’t have efficient ships unless they are also structurally safe. We have invested heavily in research and we have the depth of expertise in our hydrodynamics and structures teams to address this challenge."
At SMM in Hamburg LR is releasing its Marine Technology Report, The Future of Shipping: Issue 01, new generations of large container ships. This report, available on request, details the background work and science of understanding the forces involved in large container ship design and operation.