A sad postscript to a summer tragedy on Lake Constance: German authorities say testing has found no technical defects in the diving equipment used by two experienced tech divers who died after an emergency ascent in early August.

The incident happened on 2 August at the Tennisplätze dive site in Überlingen, a town on the German shoreline of the lake. A 46-year-old woman and her 64-year-old dive partner were diving at roughly 80 metres when they began an emergency ascent. Police reports say the man was already unconscious on the way up; the woman lost consciousness shortly after surfacing, while still in the water. Despite resuscitation attempts at the scene, both died.

The pair have not been formally named by police, but tributes from friends describe them as highly seasoned technical divers. The woman is widely believed to be Séverine Bär, a longtime contributor to the German diving publication Wetnotes.

A spokesperson for the Konstanz public prosecutor's office told broadcaster SWR that police and prosecutors examined the equipment and found no indication of a technical fault. The post-mortem examination is described as extensive and is not yet complete, so no cause of death has been given. Crucially, what prompted the emergency ascent at 80 metres remains unknown — meaning the central question of this case is still open.

Lake Constance might not be the first place travellers associate with deep technical diving, but the lake has an established dive scene, and sites around Überlingen attract trained divers from Germany and beyond. It is a reminder that even freshwater diving at depth is serious, cold, low-visibility work, and that emergency ascents from 80 metres carry grave risks regardless of how well-maintained a kit is. For the vast majority of visitors, the lake is better known for swimming, sailing and lakeside cycling between Germany, Austria and Switzerland — and for anyone without deep technical training and proper support, it stays that way.

For divers, the takeaway is sobering: investigators appear to have eliminated gear failure as a factor, which shifts attention back to physiology, planning and whatever went wrong at depth. Answers may yet come when the post-mortem concludes.

Reported by Dive Magazine.