What is a safe speed in restricted visibility?
According to this site - MCA orals the answer is:
(a) A speed that you can stop in half the visible distance you can see, so you can maneuver out of danger in the other half (if the visibility is zero, then minimum speed that you can keep your course.That's what is known as the half-distance rule. Even my outdated edition of Farwell's acknowledges this rule is out of date. According to my sixth edition (1985) recent court rulings have allowed higher speeds but "not more then a knot or two"
However this article, Safe Speed in a Fog; Ancient Rules in a Modern Age (PDF) says what most mariners know to be true:
We all know that hardly any master will reduce speed in bad visibility nowadays. Instead radars and other electronic equipment are relied uponand
We have experienced a tremendous technological development during the past 30 – 40 years while the rules have been static, in fact the present rules on speed in restricted visibility are based on the 1897 rules. And they do not recognise radars as a reliable instrument. This is in contradiction to how radars are viewed in other industries i.e. aviation and military and indeed to actual practise by the maritime community as well.Why are mariners faced with this dilemma, that normal practices would be found in violation of the rules in the event of an incident?
The article argues that the rules need to be updated and quotes from Charles Perrow's Normal Accidents:
The navigation rules have developed to aid the courts in finding fault rather than aiding the ships in avoiding accidentsThe author, Tor Lund, argues that:
Instead of taking any proactive efforts, administrations seems to be reactive; merely sending out occasional “notices” telling mariners to strictly follow the rules although they know that these notices will not be followed. This behaviour is contrary to what can be seen in other modes of transportation i.e. road, rail and air where authorities as well as other interested parties are proactive in order to constantly improve their systems and rules.I agree, my derriere is hanging out too far already, time for an update taking into account such things as radar, AIS, VHF and VTS and other modern aids.