Thirty Days Hath September

In my last post, I alluded to the fact that after the 1970s oil shocks, that Navy ships were limited to a transit speed of sixteen knots, absent operational urgencies.[1] Let me follow up on that a little.

You might have heard of the tragedy of the USS Indianapolis. That ship was torpedoed and sunk, very late in the war, by a Japanese submarine.[2] Because of a comedy of errors on behalf of a lot of officers, nobody realized that the ship was lost for four days. In that time, over half of the men who survived the sinking died from exposure or shark bite.

Out of that tragedy, the Navy developed the Movement Reporting System, or MOVREP. A MOVREP was a sailing plan, similar to an aircraft flight plan in concept. A MOVREP set out the time a ship was leaving port, the time it was going to arrive in port (or on station), the times the ship was to pass by certain positions (latitude and longitude) and the course and speed between positions. In essence, the position points were dictated by the need to change course and since a great-circle sailing plan had a lot of course changes, MOVREPs could be rather detailed. Ships were allowed to deviate a certain distance off the course line and there was a time window for the position points (plus or minus four hours, if I remember correctly).

The idea was that if a ship went out of contact, at least the Navy would know where to go looking for her.

This is no shit:

There was a ship that was supposed to go from a port visit in one nation to a port visit in another nation. Pursuant to the fleet commander's scheduling order, the ship was to get underway at 1200 local time on September 28th and arrive at 1000 local time on October 2nd. A few days before, the Navigator[3] and his Chief Quartermaster plotted out the courses and distances necessary to go from Port A to Port B. When they did that, the Navigator saw that they would have to transit at a speed of about 24 knots.

That was a puzzle, for the Navigator knew of no reason why they had to go so fast. The Navigator then added in twenty-four hours to the transit time and bingo: That resulted in a sixteen knot transit speed. It was clear to him, at least, that somebody in the Fleet staff had forgotten that September has only thirty days.

He drafted his MOVREP and took it to the Captain. In the "remarks" line, he had something snarky like "transit speed would be 16 knots if September had 31 days." The Captain read it over; he told the Navigator that there were no points awarded for being right if it embarrassed the staff of a three-star admiral. The Captain struck the remarks line, replaced it with "none" and had it sent out.[4]

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[1] This applied to nuclear-powered ships as well as oil-burning ships. The thinking was limiting the transit speeds of nucs would prolong the time between nuclear refuelings.
[2] W. Graham Claytor received the Medal of Honor for his rescue efforts.
[3] This was in the days before the XO was required to be the Navigator. After that time, the junior officer who actually did the work was designated the "Navigator's Assistant" or the "Navigation Officer" or something like that there.
[4] The ship sailed four hours before the MOVREP departure time and arrived four hours after the arrival time in order to save some fuel.