Question 627Navigation General

The correct answer is D) Annually. The Flinders bar and quadrantal spheres are used to compensate for permanent magnetism on a vessel's compass. These components must be tested and adjusted annually to ensure the compass remains properly calibrated. This is a requirement set forth in the regulations governing the maintenance and testing of navigational equipment on U.S. Coast Guard certified vessels. The other options are incorrect because A) the Flinders bar and quadrantal spheres are subject to permanent magnetism and do require regular testing, B) annual testing is the required interval, not every five years, and C) semiannual testing is more frequent than the regulatory requirement.