3 Cruise performance
Clasification Society 2024 - Version 9.40
Statutory Documents - IMO Publications and Documents - International Codes - HSC 2000 Code - International Code of Safety for High-Speed Craft, 2000 – Resolution MSC.97(73) - Annex 9 - Definitions, requirements and compliance criteria related to operational and safety performance - 3 Cruise performance

3 Cruise performance

  3.1 This test is to establish the craft performance and accelerations experienced during cruise modes with no passenger load or cargo load during the following conditions:

  • .1 normal operation conditions are those in which the craft will safely cruise at any heading while manually operated, auto-pilot assisted operated or operated with any automatic control system in normal mode; and

  • .2 worst intended conditions, referred to in 1.4.57 of this Code, are those in which it shall be possible to maintain safe cruise without exceptional piloting skill. However, operations at all headings relative to the wind and sea may not be possible. For type of craft having a higher performance standard in non-displacement mode, the performance and accelerations shall also be established at displacement mode during operation in the worst intended condition.

  3.2 Operation levels, as defined in 3.1, shall be established and documented by full-scale tests in at least two relevant sea conditions and in head, beam and following seas. It shall be shown that the period of every test (run) and the number of series are sufficient for achieving reliable measurements. In every sea state tested, the aggregate time in each direction shall not be less than 15 min. Model tests and mathematical simulations could be used to verify the performance in the worst intended conditions.

Limits for normal operation condition shall be documented by measurements of craft speed, heading to the wave and interpolation of measurements of maximum horizontal accelerations in accordance with 2.4 of annex 3. Measurement of wave height and period shall be made to the maximum extent practicable.

Limits for worst intended condition shall be documented by measurements of craft speed, wave height and period, heading to the wave and by root mean square (RMS) values of horizontal accelerations in accordance with 2.4 of annex 3 and of vertical accelerations close to the craft longitudinal centre of gravity. RMS values could be used for extrapolation of peak values. To obtain the expected peak values related to structural design load and safety levels (one per 5-min exceedance), multiply the RMS values by 3.0 or

where
= N is the number of successive amplitudes within the relevant period.

If not otherwise verified by model tests or by mathematical calculations, it might be assumed a linear relation between wave height and accelerations based on measurements in the two sea conditions. The worst intended conditions shall not exceed 150% of the more severe of the two measured sea conditions. Limits for worst intended condition shall be documented both related to passenger safety in accordance with 2.4 of annex 3 and related to the actual structural design load of the craft.

  3.3 The tests and verification process shall document the limiting seas for safe operation of the craft:

  • .1 in normal operation at 90% of maximum speed the accelerations shall not exceed safety level 1 in annex 3 with an average of one per 5 minute period. The craft operating manual shall include detailed description of the effects of speed reduction or change of heading to the waves in order to prevent exceedance;

  • .2 in the worst intended conditions, with reduced speed as necessary, the accelerations shall not exceed safety level 2 in annex 3 with an average of one per 5 minute period, nor shall any other craft characteristic motion such as pitch, roll and yaw exceed levels that could impede the safety of passengers. In worst intended conditions, with reduced speed as necessary, craft shall be safely manoeuvrable and provide adequate stability in order that the craft can continue safe operation to the nearest place of refuge, provided caution is exercised in handling. Passengers shall be required to be seated when safety level 1 in annex 3 is exceeded; and

  • .3 within the actual structural design load for the craft, with reduced speed and change of heading, as necessary.

  3.4 Turning and manoeuvrability

The craft shall be safely controllable and manoeuvrable during:

  • .1 hull-borne operation;

  • .2 operation in non-displacement mode;

  • .3 take-off, landing;

  • .4 any intermediate or transition modes, as applicable; and

  • .5 berthing operations, as applicable.

Parent topic: Annex 9 - Definitions, requirements and compliance criteria related to operational and safety performance
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