2.4 Means should be provided for transmitting measured speed and distance run information to other equipment fitted on board. In this regard:
.1 the information on the all speed and distance parameters, including direction should be transmitted in accordance with the relevant international marine interface standards*; and
.2 additionally, when the equipment is used for measuring forward speed, then the information may be trasmitted using closing contacts and, if so, this should be in the form of one contact closure each 0.005 nautical miles run.
2.5 If equipment is capable of being operated in either the "speed through the water" or "speed over the ground" mode, mode selection and mode indication should be provided.
2.6 If the equipment has provision for indicating speeds other than on a single fore and aft direction, then both the forward and athwart speeds should be provided either through the water or over the ground. Resultant speed and direction information may be provided as a display selectable option. All such information should clearly indicate the direction, mode and validity status of the displayed information.
3 ACCURACY OF MEASUREMENT
3.1 Errors in the measured and indicated speed, when the ship is operating free from shallow water effect and from the effects of wind, sea bottom type, current and tide, should not exceed the following:
.1 for a digital display - 2% of the speed of the ship or 0.2 knots, whichever is greater;
.2 for an analogue display - 2.5% of the speed of the ship, or 0.25 knots, whichever is greater; and
.3 for output data transmission - 2% of the speed of the ship, or 0.2 knots, whichever is greater.
3.2 Errors in the indicated distance run, when the ship is operating free from shallow water effect and from the effects of wind, current and tide, should not exceed 2% of the distance run by the ship in 1 h or 0.2 nautical miles in each hour, whichever is greater.
3.3 If the accuracy of devices to indicate speed and distance run can be affected in use by certain conditions (e.g. sea state and its effects, water temperature, salinity, sound velocity in water, depth of water under the keel, heel and trim of ship), details of possible effects should be included in the equipment handbook.
4 ROLL AND PITCH
The performance of the equipment should be such that it will meet the requirements of these standards when the ship is rolling up to ± 10°and pitching up to ± 5°.
*Refer to IEC Publication 61162
