Hello Wayne,

There is a possibility to know more about both events.

At first the report speaking about the U-Boot losse is hold near Paris at "Service Historique de la Marine" (French Navy Historic Department) in Vincennes. Box 45, file 5715.

Secondly the report dealing with the fate of CELIA is hold at the same department. Box 69, file 7918. The sinking occurred on 2.2.1918.

I have no time to go there in the next months but if you can't find any French guy who is able to go in Vincennes and help you, keep my address and get in touch with me in a few months.

An other possibility is to ask directly to the "Service Historique de la Marine" but I can't assure you that they'll send you copies of both files for free.
Take care with the registration (particularly the boxes) because the files used to be hold in boxes and they've been microfilming on roll since 2 or 3 years only. Most of the time the number of the roll is the number of the box but you should tell them that you have only the number of the former box.

Their postal address is
Service Historique de la Marine
Château de Vincennes - Pavillon de la Reine
BP 112
00481 Armées
France

Their website address is
[www.servicehistorique.sga.defense.gouv.fr]

Best regards,
MAX