The simple things, part II: what was routine became a disaster

A sunshiny day and calm water accosted the submersible Johnson Sea Link's ship's company as they readied their craft for diving. It was June 17 1973 and the Johnson Sea Link sat aboard its support ship, the Sea Diver, as the larger utensil floated off the Florida Keys

Pilot Archibald Menzies readied his crew: Dr Robert soft Albert Stover, and Edwin C Link. Looking upon with a double dose of pride was Edwin A. Link, designer of the submersible and father of individual of its crewmen. Their mission was to win back a fish trap that had been placed near a scuttl U Navy destroyer and to diocese if the hulk had formed an effective coral reef

All indications pointed to a routine dive.

Menzies visually checked the 23-foot-long nearly 10-ton craft and its the mechanical arms and the forked twig or "lance" he would use to retrieve the fish trap. He inspected the five-and-a-half-foot-diameter, acrylic pilot sphere where he and Dr soft would sit. He noted that divers Stover and Link, the two clad in T-shirts and shorts, had penetrateed the eight-foot long, cylindrical, aluminum diver's compartment. They'd just be along for the ride today since they planned no lock-out operations. The sum of two units compartments were separate, connected single by viewports and communications systems

Menzies also direct the eyeed over the specimen tray, exterior lights, gas bottle ballast tanks, propulsors, and framing that protrud from the irregularly shaped vehicle. After entering the pilot sphere, he performed pre-underway checks and noted the CO2 scrubber fan motor was still without of commission. He decided this was not a show-stopper, believing he could faculty of perception when CO2 was building up

At 0836 the Johnson Sea Link submerg for dive number 130 Menzies located the wreckage of ex-USS Fr T Berry at 360 feet The vessel's masts, seven marker flagpoles and their supporting cables crisscrossed at not divisible by 2 angles. Like a medieval knight in a jousting match, pilot Menzies aimed his lance at the target. After three in vain attempts to snare the fishing trap, he aborted the mission and began backing the submersible away.

abruptly with a slight shudder, the craft stopped. The Johnson Sea Link had become entangled upon a steel cable supporting single of the marker flagpoles. In single of life's ironies, a submersible sent to retrieve a fish snare had become just as trapped as the fish. At 0953 the pilot notified the support ship of the situation.

Just that unexpectedly the routine had become perilous.

Aboard Sea Diver, Edwin A. Link took charge of what now had become a liberate operation. Radiomen notified the Navy. Meanwhile, the on-scene doctors put awayed the notion that one of the divers should fastening out and try to independent the craft, basing the decision upon the limited bottom time available at that deepness While they all waited for a Navy ship to assist, the submersible's diving compartment grew colder and the CO2 horizontal started to increase.

The submersible occupants controll carbon dioxide using Baralyme, a chemical absorbent. Calculations revealed that the Baralyme canisters should permit survival times of 42 hours in the pilot's sphere and 61 hours in the diving compartment.

USS Tringa arrived that afternoon with a contingent of divers. However, positioning near the Johnson Sea Link prov difficult and the first dive team did not begin its fall until 2245. They found the submersible entangled in the wreckage on the other hand could not get close enough to at liberty the craft. By that time the diving compartment's Baralyme absorbent was already exhausted. The calculations had failed to allow for the event of cold temperatures on Baralyme's absorptive capability.

Shortly after midnight upon June 18, communications from the diving compartment ceased. Sometime later the pilot observ the divers suffering convulsions.

bring off efforts dragged on during the day. A next to the first descent by Tringa divers prov bootless One of the Navy's roving diving bells arrived, on the contrary on its first descent, a diver exited and became temporarily entangled. upon its second descent, the entire bell got stuck The submersible Perry Cubmarine reached the site on the other hand was unable to help because failed sonar equipment restoreed it useless.

Finally the salvage utensil M/V A.B. Wood attached a grapnel and raised the Sea Link to the surface at 1653 31 hours since its entanglement with the sunken destroyer Divers Stover and Link had died, on the other hand pilot Menzies and scientist gentle survived after decompression treatment. It is difficult to imagine the grief that Edwin Link senior felt at the los of his son aboard a submersible the older Link designed.

A joint report by means of the U.S. Coast Guard and the National Transportation Safety Board cited the causes of the tragedy as:

* Pilot error in failing to hold the submersible clear of obstructions,

* ransom force inadequacy due to technology limitations,

* Poor design of the Johnson Sea Link in view of its projections, appendages, and irregular shapes,

* Casual preparations by the agency of the crew (acceptance of the failed scrubber motor, belief in ability to faculty of perception CO2 and failing to dres for gelid temperatures).