This paper presents an analysis of local ice loads measured during full-scale field trials conducted in 2014 with a totally enclosed motor propelled survival craft (TEMPSC) in controlled pack ice conditions. These data were collected as part of an ongoing research program that aims to identify the limitations of conventional TEMPSC operating in sea ice environments and to provide insight as to how these limitations might be extended. During the 2014 trials, local ice loads were measured at two locations on the TEMPSC's bow area. These loads were the most severe measured to date and corresponded to an average ice floe mass that was approximately 1.25 times the mass of the fully loaded TEMPSC. The event-maximum method of local ice pressure analysis was used to analyze these field data to improve understanding of the nature of ice loads for such interactions and to evaluate the suitability of this approach for design load estimation for TEMPSCs (i.e., lifeboats) in ice. The event-maximum method was adapted for the present application, so as to link exceedance probabilities with design load levels for a given scenario. Comparison of the 2014 results with a previous analysis of 2013 field trials data supports earlier conclusions that these interactions are highly influenced by kinetic energy, since more massive ice floes are observed to impart significantly higher loads on the lifeboats. Illustrative examples examining the influence of ice concentration and sail-away distance have also been provided. The work establishes links between extreme loads and the exposure of the lifeboat to ice for different operating conditions. Based on this work it is concluded that the event-maximum method provides a promising approach for establishing risk-based design criteria for lifeboats if field data are available which adequately represent ice conditions encountered during the design life of the lifeboat.

References

References
1.
Kennedy
,
A.
,
Simões Ré
,
A.
, and
Veitch
,
B.
,
2010
, “
Operational Limitations of Conventional Lifeboats Operating in Sea Ice
,”
Proceedings of ICETECH
, Anchorage, AK, Paper No. ICETECH10-103-RF.
2.
Bercha
,
F.
,
2008
, “
State of Art of Arctic EER
,”
Proceedings of the 8th International Conference and Exhibition on Performance of Ships and Structures in Ice (ICETECH 2008)
, Banff, AB, Canada, Paper No. 121-RF.
3.
International Organization for Standardization (ISO 19906,)
,
2010
,
Petroleum and Natural Gas Industries—Arctic Offshore Structures
.
4.
Jordaan
,
I. J.
,
Maes
,
M. A.
,
Browne
,
P. W.
, and
Hermans
,
I. P.
,
1993
, “
Probabilistic Analysis of Local Ice Pressures
,”
ASME J. Offshore Mech. Arct. Eng.
,
115
(
1
), pp.
83
89
.10.1115/1.2920096
5.
Taylor
,
R. S.
,
Jordaan
,
I. J.
,
Li
,
C.
, and
Sudom
,
D.
,
2010
, “
Local Design Pressures for Structures in Ice: Analysis of Full-Scale Data
,”
ASME J. Offshore Mech. Arct. Eng.
,
132
(
3
), p.
031502
.10.1115/1.4000504
6.
Kennedy
,
A.
,
2010
, “
Limitations of Lifeboats Operating in Ice Environments
,” Master of Engineering thesis, Memorial University of Newfoundland, Faculty of Engineering and Applied Science, St. John's, NL, Canada.
7.
Simões Ré
,
A.
,
Veitch
,
B.
,
Kuczora
,
A.
,
Barker
,
A.
,
Sudom
,
D.
, and
Gifford
,
P.
,
2011
, “
Field Trials of a Lifeboat in Ice and Open Water Conditions
,”
Proceedings of the Port and Ocean Engineering Under Arctic Conditions
, Montréal, QC, Canada.
8.
Simões Ré
,
A.
,
Veitch
,
B.
,
Gifford
,
P.
,
Kennedy
,
E.
,
Kirby
,
C.
,
Kuczora
,
A.
, and
Sudom
,
D.
,
2012
, “
Performance and Survivability of Totally Enclosed Motor Propelled Survival Craft (TEMPSC) in Ice and Open Water Conditions
,” Ocean, Coastal and River Engineering Portfolio, Paper No. OCRE-TR-2012-07.
9.
Kennedy
,
A.
,
Simões Ré
,
A.
, and
Veitch
,
B.
,
2014
, “
Peak Ice Loads on a Lifeboat in Pack Ice Conditions
,”
Proceedings of the Arctic Technology Conference
, Houston, TX.
10.
Billard
,
R.
,
Rahman
,
M. S.
,
Kennedy
,
A.
,
Simões Ré
,
A.
, and
Veitch
,
B.
,
2014
, “
Operability of Lifeboats in Pack Ice: Coxswains' Skill and Design Factors
,”
Proceedings of Arctic Technology Conference
, Houston, TX, Paper No. OTC 24610.
11.
Rahman
,
M. S.
,
Taylor
,
R. S.
,
Simões Ré
,
A.
,
Kennedy
,
A.
,
Wang
,
J.
, and
Veitch
,
B.
,
2014
, “
Probabilistic Analysis of Local Ice Loads on a Lifeboat
,” Banff, AB, Canada.
You do not currently have access to this content.