# The Fishing Vessels (Safety Provisions) Rules 1975, Paragraph 2


The magnet shall have ample directive force. In the United Kingdom a period of 18 to 22 seconds after a deflection of 40 degrees at a temperature of about 15°C shall be deemed to comply with this requirement. For the purposes of this paragraph a “period” is the time taken by a complete oscillation of the card after a deflection of 40 degrees, a swing past the position of rest, and back again to the completion of its swing on the side to which it was originally deflected.

---
Source: https://www.legislation.gov.uk/uksi/1975/330/schedule/14/paragraph/2 (the official version)
Page: https://openlegislation.uk/fishing-vessels-safety-provisions-rules-1975/schedule-14/paragraph-2
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.