Before the current numbering system commenced in 1997, all M Notices, whether of a mandatory, recommendatory or advisory nature, were numbered in one series with an “M” prefix. Many of these old notices have now been either cancelled or re-issued as MSNs or MGNs. Most of those remaining are recommendatory or advisory, such as M. 474 (Explosions in Diesel Engined Vessels). However, MCA includes them on its website as “Merchant Shipping Notices”, giving the impression that they have mandatory status.
Why do some M Notices have numbers prefixed by the letter “M” and not “MSN”, “MGN” or “Min”?
