Yes - drawing while scubadiving is an amazing experience! This is my second attempt to keep notes and draw under water. I used rite-in-the-rain sketchbooks and regular #2 pencil - just like the last time - but I also tried a red-and-blue pencil - and it was GREAT! Much softer lead was probably the most useful feature (no matter how soft the regular graphite pencil - it still feels very hard at the depth). But having some color was a blast! The only thing I would change is next time I would take several pencils with me on a trip - sea water and depth make pencils fall apart pretty quickly, not to mention runaway pencil ascents and pencils swimming away during boat boardings :)
All in all over 40 pages were filled and you can see many of the in the special set I created:
http://www.flickr.com/photos/23173190@N07/sets/72157633458267134/with/8724434856/
And here are some of my favorite moments from seven days of liveaboard experience:
(Thank you Kate H. for the photo of me at work!)