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Foxboro Decomputer Mark I history dive computer kit

From analogue to digital - the rise of the dive computer

In a 1951 secret meeting at the Scripps Institution of Oceanography in California, members of the US Navy Committee for Undersea Warfare and Underwater Swimmers discussed improvements to scuba diving gear. Top of their list was a foolproof way of monitoring nitrogen loading.

Two years later two Scripps researchers, Groves and Monk, published a paper that set out the functionalities needed for a decompression device. They said such a device must calculate three things – decompression during the dive, the remaining nitrogen in the human body from previous dives and, based on this information, an optimised, faster ascent rate. Groves and Monk suggested the use of an electrical analogue computer to measure both decompression and air consumption.

American manufacturer Foxboro came up with the Decomputer Mark I in 1955 (above). It was the first analogue dive computer. A needle indicated danger during an ascent by moving towards a red zone on the display. After several test dives, the US Navy found the device to be too inconsistent – despite their efforts, the use of dive tables was still far more accurate.

It was back to the drawing board. In 1963 the SOS Poseidon 5 was introduced. It automatically calculated how long decompression stops should be based on dive depth and bottom time. However, imprecise calculations for deep and repetitive dives gave it the nickname ‘Bends-o-Matic’ and the US Navy advised against its use for recreational diving.

The same year the market saw the first electric analogue device – the TRACOR. The unit ran on two batteries, but the high power consumption, especially in cold waters, resulted in limited dive times and a worrying rate of system failure.

Next up was the MARK V S developed by the DCIEM (Defence and Civil Institute for Environmental Medicine). It was the first dive computer to tick all the boxes and was sold to industrial and military agencies in the 1960s but was not available to the public.

In the late 1970s dive computers went digital. The XDC-1 was a desktop device designed in 1979 for laboratory purposes and looked like a cash register. The device built the foundation for the improved XDC-2 and XDC-3, or CyberDiver that became the first digital portable computer and 700 units were sold between 1979 and 1982. The later XDC-4 worked with gas mixes, but was too expensive for the mass market.

In the 1980s the technology quickly improved. In 1983 the Orca Edge hit the market as the first commercially viable dive computer. The model was based on the US Navy dive tables but did not calculate a decompression plan. Its design was ahead of its time – it resembled an iPod Nano. However, production capacity was only one unit a day. It was never going to emulate Apple’s sales figures.

A year later, the Decobrain arrived and the modern recreational dive computer was born. It had all the features we have come to expect from a dive computer, including calculated ascent times and an integrated warning system for fast ascents. The Decobrain was also the first dive computer to achieve success in the European market.

DACOR’s follow-up model Microbrain was the first industrial scaled dive computer and the first one using a silicon chip.

In 1986 a little known Finnish company, Suunto, came out with the SME-ML. The computer had all the essential features and was able to store 10 hours of dives, which could be accessed any time. This, and the simple design, was key to its success and marked Suunto’s break into dive gear manufacturing. It took another decade before the Finns became market leaders.

In 1987 the Swiss company UWATEC introduced the Aladin that swept aside all rivals. The unattractive, chunky, grey housing could be seen strapped to wrists from the Red Sea to the Barrier Reef. Soon more divers were using computers than not – and more were using Aladins than anything else.



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