C3 Fiber Optic Repair (attempt) 

Nice work! Have you considered a small dab of clear epoxy between the ends and only use one of the crimp fittings, the metal ferrule only? Maybe that would provide better alignment and the epoxy would be a decent conductor of the light. Then shrink wrap the whole assembly. I would think that would be a stable and water tight connection.

I agree with ABinNC. An air gap will cause light loss. A little dab of clear epoxy'll do ya, bridging that gap and conducting more light...I think.

Fiber optic data cables are very cheap. I bet you could use some multimode OM3 from monoprice. I just checked and 15 meters is $6.30 Product # 43105. Good luck with your restoration 👍