Underwater volumetric lights

[pokeit]

Hi All! Happy New year!

Hopefully someone can help! I'm trying to do an underwater scene with submarines in a fog volume casting light from spots on the hull. Basically spotlights in fog.

I had some partial success with the built in spotlight- but 1: Couldn't see a light 'source' and 2: no matter what i did you could see the volumetric 'cone'

I'm now using ies lights and that appears quicker to render and doesn't have the 'cone' edge of the built in spotlight.

Can anyone cast any light (Hah!) on the best method for creating an underwater spotlight look (Or spotlight in fog look) without the weird light cone interactions?

Many thanks in advance

Poke