Hello Michael,

Thank you very much for your very informative answer. I was interested because I am researching a WW2 attack on a German U-Boat where the aircrew all saw a green luminescence around what appeared to be the conning tower of a German U-Boat. I was mainly interested to see whether this could possibly happen and whether the submerging vessel could create a green luminescent trail. The explanations in the thread you directed me to seem to prove that it can happen. It also makes sense when you read that the plumes of water generated by the depth charges dropped on that occasion appeared like green smoke.

In the Admiralty response to the pilot's attack report, it was stated that they had no idea what the green luminescence could be. The RAF base commander's report suggested that it could be an accidentally discharged recognition flare. I think the bioluminescence report is more feasible.

Best Regards
Neville