Planning and Risk Assessment (Vol 2)

(By Alexander Brovin et al, Loly Tsoy et al ; INSROP Working Paper No. 34 – 1996, I.5.5)

The Project consists of two parts carried out at the Arctic and Antarctic Research Institute (AARI) and the Central Marine Research and Design Institute (CNIIMF).

The AARI part deals with the current status of specialized ice information for organization and planning of shipping along the NSR, as well as risk assessment of ice navigation for ships.

Specialization of ice information for shipping in the Arctic Region as an independent research direction ha been developed at AARI’s Ice Navigation Research Laboratory for 30 years. A detailed development of specific specialization issues, creation of calculation methods for estimating the difficulty of ice navigation and extensive experience in providing support to navigation along the NSR governed the AARI leadership in this field.

Materials presented in INSROP Working Papers Nos. 23 and 34 (Vols. 1 and 2), provide a general understanding of ice information required for planning of sea operations along the NSR.

Volume 1 is largely focused on an analysis of studies performed in the previous years regarding some aspects of specialized ice information for shipping in Russia. Volume 2 is devoted to conceptual development of ice information for planning of navigation along the NSR and new investigations in this field.

In particular, the following is included:

• main stages of the development of specialized ice information for shipping in Russia;
• a concept of the ice support system for planning of sea operations along the NSR (from 6 months to 10 days);
• assessment of the influence of certain ice cover characteristics on ship motion;
• ice-navigation and operating indicators applicable for planning of shipping along the NSR and possibility of prediction;
• a description of the empirical-statistical method for a quantitative assessment of the difficulty of ice navigation (the QAD model) and possibilities of improvement;
• typification of ice navigation conditions along the NSR with a time interval of 10 days, a month, a season, a navigation period;
• a description of the database on ice damage to ships and reception conditions set up at the AARI.

Further studies within the INSROP framework can include development of scenarios for planning of sea operations along the NSR under specific years (reference years by ice conditions). Here, cost-effective estimates are quite desirable.

Also important is creating a system for ice support for successive planning of navigation along the NSR, in particular, climatic estimates of ice navigation conditions on the segments and along the entire NSR (based on the QAD model), obtaining of ice-navigation indicators for the whole series of ice observations along the NSR (40-50 years). In addition, it is significant to predict ice-navigation indicators and develop algorithms of navigation recommendations for certain sea operations.

The CNIIMF part deals with problems of the safety of navigation in the Arctic in connection with hull ice damage of cargo ships and icebreakers. Generalization and analysis of statistical data on the hull ice damage of ships sailing along the NSR have been made and the comparative assessment of the safety of navigation in ice of

icebreakers and ships of different ice classes have been given. An assessment was also given of the probability of damage of different sizes and areas of the hazardous operation of ships characterized by the highest frequency of ice damage. The results obtained permit an assessment of the risk of occurrence of hazardous hull ice damage when icebreakers and ships with different ice strengthening navigate along the Northern Sea Route.

The main conclusions drawn from the analysis:

• the most damaged hull areas of icebreaking cargo ships are the forepeak, bilge strakes and adjoining bottom strakes in the ship's fore- and middle body;
• a relatively high level of damage to the shell plating bottom strakes is attributed both to the frequent use of escort by icebreakers in a close tow under heavy ice conditions and to the shallow water in the NSR;
• frequency of icebreaker damage is substantially higher than that of icebreaking cargo ships operating in the Arctic mainly under icebreaker support;
• Most ice damage to icebreakers occur in the transitional area between the forepeak and the middle part of hull and in the middle part proper;
• ice damage to linear icebreakers is mainly concentrated to bilge strakes and the flat portion of bottom;
• the probability of heavy ice damage with a deflection of 150-200 mm and more (when cracks appear in the hull plating) does not significantly differ for icebreakers and icebreaking cargo ships and is rather high (15-20% of dents are 100 mm deep and more).

The latter fact indicates that it is advisable in the design of ships for Arctic navigation to provide double sides and double bottoms around the cargo holds.

Alexander Brovin et al, Loly Tsoy et al, 1996, Planning and Risk Assessment (Vol 2), INSROP.©