DARK WATERS: Programming in Small Places

I happened to be seated across from Brian Wruble at a dinner and somehow we got to talking about programming in the old days when the only languages were machine languages and memory was measured in Ks.  He told me about the Sperry Mark XV, a 1960s computer with 12,000 twentyone bit words.  Then he told me where he programmed it, in a secret miniature US nuclear sub designed to crawl on the sea floor at depths over half a mile!  Turns out there is a book about this sub: Dark Waters by crew member Lee Vyborny and writer Don Davis.

It is really a book about the submarine although my favorite parts are about programmer Wruble squeezing critical functionality into his tiny computer and trying to keep the thing working in the tough environment of a submarine designed to stay immersed for weeks at a time.  Wruble was not Navy, he was the Sperry Field Engineer that came with the computer.

The NR-1 was a cold war secret.  It didn’t appear on the Navy’s roster of ships and its budget was hidden.  According to the book, one of its missions was to plant and service deep sonar arrays that the US used to track the movement of Soviet subs.  It is possible that it also disabled similar devices planted by the Soviets; it certainly sought them out.  It was instrumental in tapping Soviet undersea cables.

The sub with it 12 man crew was successful in finding a lost F-14 and retrieving its top-secret Phoenix missile in almost 2000 feet of water Northwest of Scotland.  The recovery was a race with Soviet trawlers and, at one point, the NR-1 itself became dangerously ensnared in what were probably trawler nets.

Hyman Rickover insisted the sub be built and it is one more testimonial to his famous stubbornness.  Vyborny doesn’t love Rickover; the Admiral could be very egotistical and cruel.  But Rickover did go on the two day Alpha Test dive below the design depth of 3000 feet; that’s leadership!  And, after a Captain of the NR-1 thought that his career was over when he decided to break most of the rules of the nuclear fleet in an emergency situation, he was amazed to find that Rickover instead had arranged for a brass band to meet the ship and a Presidential Meritorious Service Award for the skipper who knew when to throw away the book.

Oceanographers aboard a scientific cruise on the NR-1 were the first to find that the depths are not a placid place.  In fact there are strong currents and flows there – exactly the opposite of the then conventional wisdom.  Also a threat to the boat which had been designed on the assumption that it would roll along a bumpy bottom – it had wheels – in calm waters.

Back to Sperry Mark XV.  At Rickover’s insistence, 30 day testing of the NR-1 was done in a plastic tent at high temperature and 100% humidity.  Brian Wruble practically lived in the tent which was probably comfortable compared to his next assingment aboard the NR-1.  With its small memory, dates were stored as a single digit in the Mark XV.  Brian, who by this time was working in a Wall Street Research boutique, came back as a consultant to find what turned out to be a “Y70” bug.