PUBLICATIONS NEWS
Discussion invited on IJSCT papers
T
he following papers to be • IJSCT 87: An Investigation Into A differential equations of motion for the
published in the International Method For Determining The Stability four falling phases, i.e., sliding phase,
Jour na l of Sma l l Craf t Of Small Craft Without Reference To rotation phase, free-fall phase and water
Technology are now available for Hydrostatic Data entry phase of the lifeboat were solved in
discussion: the time domain. The behaviour of the
A J Murphy and R W Birmingham, lifeboat has been studied for different
• IJSCT 77: United Kingdom Newcastle University, UK angles of launch skid, i.e., Θ= 30°, 40°
Regulation Of Yachts and 60°. The initial falling height of the
The assessment of the stability of small boat is fixed to 1.75m. The regular wave
D W Ralph, Maritime and Coastguard craft can be difficult in the absence of with amplitude of 0.5m and period of 2.0
Agency, UK hydrostatic data when it is not possible to sec. is considered in this study. From the
use the normal inclining experiment. This mathematical simulation, horizontal and
The UK leads the world in the paper provides a thorough numerical and vertical excursions and the rotation of
regulation of large yachts. British experimental investigation in to a stability the axis of the boat have been obtained
yachts form the majority of the world assessment method, previously proposed at different time along with its horizontal
fleet, bearing in mind that this includes as a possible alternative to the inclining and vertical velocities. Accelerations and
yachts of the wider Red Ensign Group. experiment (Birmingham, 1995; 2000). forces at normal and axial directions have
Historically, yachts have been built The method uses the relationship between also been computed. In each case, the
for private use but are increasingly changes in the natural roll period of behaviour of FFLB in wave is compared
being used, remotely from the UK, in vessels given changes in roll mass moment with that in still water.
the charter market. Vessels operating of inertia. The numerical investigation
“commercially” must comply with indicates that the method will be sensitive IJSCT papers for discussion can be
appropriate Flag State legislation and, to small experimental errors although downloaded from www.rina.org.uk/ijsct_
if of sufficient size, must also comply not necessarily impossible. However, discussion.html. These PDF files can be
with and be certificated under the the conclusions of the experimental saved and viewed on screen but cannot be
provisions of appropriate International implementation of the proposed method edited or printed out.
Conventions. were that it does not ultimately provide a
sufficiently accurate stability assessment as Written comments on these papers may
• IJSCT 86: Effect Of Water Depth On to be practically viable. Nevertheless, the be forwarded using the Online Comment
Motions In Beam Seas For A Typical work provides a comprehensive follow-up form or by email to ijsct@rina.org.uk , with
Landing Craft to the earlier published proposition and the title of the paper as the Subject, and
provides further insight in the dynamics quoting the name and affiliation which will
A Rolls, M Renilson and G of a rolling vessel under experimental be printed with the comment. Illustrations
Macfarlane, Australian Maritime conditions with fastidious attention to may be forwarded as an attachment.
College, Australia; experimental accuracy. Accepted discussion will be published in
S Cannon, Defence Science and subsequent issues of the IJSCT.
Technology Organisation, Australia • IJSCT 88: Numerical Investigation Into
The Effect Of Launch Skid Angle On
A set of model experiments have been The Behaviour Of Free-Fall Lifeboat In
conducted at the Australian Maritime Regular Waves
College to investigate the effect of water
VISIToRS To
depth on the motions of a typical landing M M Karim, K S Iqbal and M R H
HEadqUaRTERS
craft in beam seas. Tests were conducted Khondoker, Bangladesh University
at different wave heights in two water of Engineering and Technology,
Long distance visitors to Headquarters
depths: deep, corresponding to a depth Bangladesh; S M H Rahman, American
included Ian Dunford from the NZ
to draught ratio of 9.0; and shallow, Bureau of Shipping, USA
Division, accompanied by his wife,
corresponding to a depth to draught ratio
daughter and grand daughter – surely
of 1.5. The influence of non-linearity on This paper presents numerical
the first time No 10 Upper Belgrave
model motion, particularly in roll, was investigation into the effect of launch
Street has seen three generations of
determined, as was the effect of water skid angle on the behaviour of the
the same family at the same time.
depth. It was shown that the motions in skid-launching free-fall lifeboat
shallow water were significantly different (FFLB) in regular waves. The boat has
to those in deep water. been treated as a rigid body when the
6 Rina affairs September 2009
RA September 09.indd 6 28/08/2009 15:38:04
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