Indeed , the reasons that Reise gave are correct , also surely the fact that any Frenchman that would leave the country to join the Allies was immediately condemned to death and nasty retaliations could affect his family (not only Gestapo but especially Vichy police ) .
There is alo another reason that outshadows the others , the Nazis Germans attacked with tanks and invaded what was considered the "Free Zone" by Vichy and under their authority in end of November 1942 , it was a pure violation of the 1940 Armistice signed , the aim was to seize 230.000 BRT of French warships and Vichy was very unhappy with this decision .
At 4h30 on the 27th of November , Nazi tanks enter Fort Lamalgue and arrest Admiral Marquis who was in charge without giving explanations , this was the signal for his headquarter Major Robin to give the "scuttling order " to the rest of the fleet docked at a few kilometers from there . During this time , tanks have problems to find the right way to the harbour and about 5 submarines managed to dodge the magnetic mines to escape , as well about 7 warships who were approx ready (Casabianca , Marsouin , Le Glorieux to Algeria , L'Iris to Barcelona , and a few other smaller surface ships who fled in time ) escapes in panic and managed to escape Luftwaffe bombing and KM submarines .
On the "Strasbourg " , Admiral Laborde ( pro-Vichy ) still can't believe why Hitler betrayed his word to not plan anything against the French Fleet , and refuses to leave his ship or scuttle it . It's only a few hours later , after Marechal Petain himself calls him and order him to abandon and scuttle the ship that he complies . He accepted the sacrifice because Petain told him it was the only way for the Marine (Navy ) to respect its serment (strong promise ) to never give any vessels to any foreign country
The result , on the night of the 27th November is out of approx 100 warships , 90% were scuttled , especially the integrality of High Seas Fleet (Oceanic Fleet ) and all greater warships like battleships . 39 vessels of light to very light tonnage will be captured , but they were sabotaged and disarmed which will be of no use to the Kriegsmarine . Operation Lila failed because Germans western force who invaded the Vichy zone , took too much time to capture the harbor of Toulon and gave the time to the sailors to scuttle the ships , and they didn't expect that the French Navy was ready to react quickly in case their ships would be raided , so the main reason was that Hitler broke the terms of armistice with Operation Lila and the scuttling order was supported (not officially ) by Vichy , cheers mate
source :
http://www.netmarine.net/forces/oper...dage/index.htm (in french sorry)
To get closer to silent Hunter III , 8 U-Boots were asked by BdU to intercept any French warship going out of Toulon on the 26th November (between Bandol and Porquerolles )
It was U-81 of Gugenberger , U-83 of Morishoffer , U-375 of Koenemkamp , U-561 of Schomburg , U-565 of Franken , U-562 , U-617 and U-77
Also , since the 7th of November , British submarines as well were posted near Toulon fleet waiting to sink any warship that would go out of Toulon harbour , it was Seraph , Sybil , P-51 , P-222 and Unseen . Unseen will be detected and depth charged by "L'Impetueuse" of commandant Barnouin , then prior to 15th of November , British sent Splendid , Sturgeon , Tribune and Unshaken