Gouffre Bob Vouay
Northing: 45.30960° Easting: 5.85445° Altitude: 2,015 m
How to find it
The easiest way to find Gouffre Bob Vouay (occasionally misspelt as "VouEy") is to follow the waymarked GR9 from the Col du Coq as far as the junction where the path to Trou du Glaz takes off to the left to traverse above slopes. Keep right, and follow the path up towards the Pas de l'Œille and the summit. At the top, rather than overcoming the last few metres of height by traversing to the right, keep going up the line of the fault onto the plateau into a small fault valley. The entrance to Gouffre Bob Vouay is associated with the arch 40 m on the left. Clamber up to the arch and free-climb into a large pit with an identifying label on the wall. Entry is gained through a rubbish bin inscribed with the words "Ad augusta per angusta" ("To triumph through hardship").
The rock arch is in the centre of the photograph, Mont Blanc in the distance
Further information
Gouffre Bob Vouay, opened up in 2009, is the highest entrance of the Dent de Crolles system, giving a through trip to Grotte du Guiers Mort of 681 m. All but the entrance series down to -60 m were explored upwards from Trou du Glaz from 1983 onward. In addition to the connection with Trou du Glaz at the top of P36, there is a second route that descends into Grotte Chevalier via Puits Maurice. Both routes are equipped for pull-throughs, but both require much traversing in complex meanders, and are not for the faint-hearted.
Spéléo Secours Isère have produced route guides for both traverses. The Gouffre Bob Vouay - Grotte Chevalier guide is available here (and a loose translation by the author is available here). The Gouffre Bob Vouay - Trou du Glaz route guide is available here (with a loose translation by the author available here).
The following cross-section drawn by Gilbert Bohec helps to clarify how it fits into the system.
Red passages indicate the Vouay - Chevalier route; blue passages the Vouay - Trou du Glaz route
A deep-zoom version of an adaptation of part of the main plan survey of the system published in Scialet 38 also shows how the cave fits into the system.
The exploration was reported in Scialet 38 in 2009, and Spelunca Magazine 117 in March 2010, and there is a full account of the cave and its exploration in Spéléo Magazine 70 (2010) by Christian Hubert and Frédéric Pétrot which includes some impressive photographs and an updated large scale survey of the southern half of the system (available on bona fide request). Apparently the route through the 300 m-long Grande Méandre was optimised and equipped in about 2013 during preparations for a Vouay - Guiers Mort - Vouay return trip, which was eventually made in 2016 (Spéléo Magazine 99, available on bone fide request). There is also a film Dans le Crolles de la Croix à la Source purportedly of the through trip from Gouffre Bob Vouay to Grotte du Guiers Mort, but it is neither very good nor very informative.
The cave is named after Robert Vouay (1923-1982), a leading French caver and founder of the Spéléo-Club de la Seine.