With a minimum depth of 32 meters and a maximum of 40, the Rubis is one of the rare U-boats in good state of conservation approachable by advanced recreational scuba divers.
This wreck is located in southern France, off the coast between St. Tropez and Cavalaire sur Mer.
Built in 1931 by Toulon shipyards, the Rubis has been launched on September 30. It is the fourth out of a series of six: the Saphir, the Turquoise, the Nautilus, the Diamant and the Perle.
Designed to deposit landmines without emerging to the surface, this U-boat measured 66 meters in length, 7 meters in width and 8 meters in height. It was equipped with a 3900 HP Vickers-Armstrong engine, which granted 8 knots speed while diving and 12 knots speed at the surface. The Rubis could dive up to 50 meters depth and sail at periscope depth of 15 meters. It was armed with a 75mm and two 13mm cannons, 32 landmines weighing 1.090 KG each, three 550 mm and two 400 mm torpedoes. The crew consisted in 45 men: 4 officers, 9 noncommissioned officers and 32 sailors.
In 1936, the Rubis sailed to Cherbourg to refine the crew training. At the beginning of the war, in 1939, it was in Bizerte under the 9th Mediterranean Fleet command based in Dundee (Scotland). The Rubis performed several missions within Norwegian waters during 1940, while the Third Reich was invading the country. After the armistice of June 20 1940, Great Britain started operation Catapult, aiming to conquer French ships. The Rubis was part of this plan and therefore changed its flag. Only 5 out of the 45 crewmembers returned to France, while the others chose to serve under the Free French Forces led by admiral Muselier.
The Rubis sailed through the whole war without damages: an uneasy exploit for that kind of ship!
In 1945, the U-boat achievements were significant: during its 28 missions it deposed 683 landmines that sunk 15 ships and 7 dredgers, sunk a 4360 tons cargo ship and damaged a German U-boat. On June 8 1945, the Rubis returned to Orano, where it was decommissioned. Until 1950, the Rubis served as a training ship.
In 1957, avoided dismantling thanks to the intercession of one of its captains, but then the general staff decided to sink it. On Jan.31 1958, the Sansone tugboat and the Desert barge took the Rubis 2.6 km off Cap Camarat. Captain Riffaud, one of the Rubis’ last captains, had the sad duty to blast the 9 kg TNT charge which, exploding astern, sunk the Rubis to a 40 meters depth.
Due to its depth, diving on the Rubis might be considered easy and the whole wreck can be explored during one dive only.
What makes this dive difficult is the constant presence of current that can be strong enough to prevent divers reaching the bottom.
French laws prohibit fixed descent lines positioning when unauthorized: this forces diving centers to set up a line time by time.
The standard dive starts from the rear since the prevalent current runs from bow to stern. The propellers are missing, removed a few years ago by some divers and the masts sheared off by the blast float in midwater.
Swimming towards the turret and looking through the now damaged metallic coating, we can glimpse the big compressed air cylinders used for the U-boat buoyancy.
Morays, conger eels and scorpion fishes show from the cracks and, being used to divers’ visits, let divers get close without any fear.
Before reaching the turret, we find one of the three trapdoors accessing the U-boat, but the passage is far too tight for trying a penetration. On both sides of the hull, we notice two big protuberances that hosted the 32 landmines part of the Rubis weaponry. Schools of breams and other fishes swim around the turret, while big hunting snappers dart from now and then.
In the front of the turret, we can see a kind of pulpit facing the bow: for sure, that was the place where the sailors guard stayed during surface sailing. Through the metal sheets, we can glimpse tangles of valves and pipes, offering an excellent shelter for flora and fauna.
We swim over the two other accessing trapdoors, both wider than the first one but still too complicated to enter. The bow raises from the bottom, giving the Rubis an evocative profile sight, almost as if still sailing.
We go back to the central trapdoor, to enter and explore inside the U-boat. Due to the narrow space, penetration must be effected one at the time, leaving our buddy at the entrance door to check from outside and prevent other divers to get in while we are inside.
Always remember that penetrating a wreck is a matter for experienced and specifically trained divers!
The space inside the wreck is really small and narrow, and the first thing that comes to mind is how extreme and difficult the conditions the 45 crew members shared were, forced to live together in this tight place during their long sailings.
WORDS and PICTURES by Aldo Ferrucci