It’s hard to say if newer designs are better or if they are just newer and different. I’m no expert but this is my take on it.
Before any formal BC devices, divers were constantly experimenting with how to deal with the problems of wetsuit compression and gas loss from the tank.
The horse collar was kind of a makeshift solution to the growing problem. It was a borrowed device from another realm, it wasn’t originally designed specifically to be a BC device for scuba diving. The later models that were adapted to scuba were still based on an inflatable life jacket.
The cold water that divers were venturing into (innovation of thick wetsuits) made bigger buoyancy problems combined with the development of larger tanks becoming available. All this created a need for a reliable and convenient buoyancy control solution.
There was also the growing interest in diving by the general public and more organized instruction, more resorts opening up around the world. Diving was being opened up to a wider cross section of the public, not just a handful of ex military divers and hardcore sportsmen and adventure types.
All this sparked more innovation with manufacturers and this about the time the stab jacket came out. It was a convenient solution to BC control in an all-in-one type of unit. The tank straps onto the jacket and you jump in, very simple.
They might not have been ideal but they were convenient and easy to train people in and they took off. Within a few years every company was making their own version of a jacket style bc.
Then weight integration came in to make it even more of an all-in-one unit by getting rid of weightbelts.
Horse collars were awkward for the general public to use. The tank had to be separate on a plastic pack with straps, the horse collar was this big stuffy thing also with straps on your front side. You had to use a weightbelt which fought with the pull of the horse collar and made it a challenge to stay flat. If you were using a larger steel tank it was quite a balancing act not to turtle with the air cell on your frontside wanting to go up fighting with the weight of the tank wanting to go down.
The jacket solved a lot of these problems but also created a new set of problems, or compromises.
Jackets didn’t hold the tank to your body as well as back packs and with all that fabric, the tank flops around. They also add a lot of inherent buoyancy that needs more weight added to offset.
The only innovation that has gone further is the Back Plate and Wing, but it is still considered a “niche” product and while they are gaining popularity with a small group they are still considered fringe. BP/W gives you the best of both worlds, the stability of a back plate (back pack) combined with buoyancy compensation.
People have figured out how to keep from face planting on the surface while using them. First, don’t overweight yourself requiring a lot of air in the wing at the surface to keep from sinking, use a heavy plate in cold water, and use heavy steel tanks. The weight of the plate and steel tank behind you will counter the lift of the wing which should not have much or any gas in it on the surface. Also, in the last 20 years, divers have become more savvy in learning how to distribute weight and fine tune trim, which didn’t seem to be a thing back in the day.
A lot has changed.
However, jackets still rule the general diving world and probably will for a very long time to come.
