I suppose it's time to start a build thread since I'm going to be starting sculpting on things soon, but I'm planning to make the tail pictured in the sketch below (life size sketch) from silicone. Scales will be cast individually from assorted hand sculpted masters.

I've worked with silicone before, but never for something this hilariously huge (the tail needs a 4x4' board to be sculpted on). My plans assuming nothing goes horribly horribly wrong is to design the tail in a way that it looks torn up and when it actually gets torn up or scuffed it will look like scars. Backup plan is just make a regular tail that's a solid color throughout :P I also have theoretical plans to stiffen the veins in the fluke, but I'll get to that when the time comes.

I should be getting a mold of some scales done later today/tomorrow that I can use to test airbrushing, thickness etc.

Monofin that will be in the fin: LeaderFin Sport Junior with a medium blade stiffness (Which you can sort of see if you look REALLY closely at the sketch - I just traced around the fin and then doodled ontop of it).

Either way, should be interesting... Might turn out great, or it might be terrible.
I'll probably post more regular updates on my twitter (https://twitter.com/squishy_works), but I'll try to update this regularly as well. There's just more cat pics on the twitter.

p.s. This is my first tail and I know it's advised against to go for full silicone but I'm gonna go for it anyway. I'll exercise reasonable training measures to make sure I don't drown myself and make sure I'm not alone while swimming. I'm also a certified SCUBA diver and have been swimming since I was 3 :P