No lifts here. We at least have fin on ladders. I need a few pulls on the manifold. Crew is always willing to help that way. I have been told that for my local boat doffing on the ladder and one of the crew pulling doubles up is NOT an option. If a dive buddy offered to pull them up, well, that’s something totally different. Passing up deco bottle is kosher if conditions permit.
Someone mentioned swell. Haha. We can get nasty chop here on the Great Lakes. Distance between waves is less than on the ocean, so yi often have very little recovery time.
We would put our own lines in the water and do the kit recovery ourselves. A few of the boats had a block and tackle arrangement which made things even easier. We wouldn't expect the crew to pull a set of twins back on board.
Even 'recreationally' we've had divers remove a set in the water due to back or mobility issues.
Removing kit in the water is not a new issue, its standard practice if you are diving from RHIB's.
The biggest safety issue is to ensure none of the lines can get picked up by the propellor.
(I don't like to hand up stages, I much prefer to clip them into the recovery line. I've seen to many disappear below the surface. Or have them removed once back on board.)
Economic pressure over the last 10 years has had an impact on the number of boats available.
The interesting thing is that the boats that have adapted to the change in diving culture, are the ones that have survived.
You are hard-pressed to find a hardboat in the UK that doesn't have a diver lift. The vast majority of the bigger boats, despite the logistic issues with fitting lifts, now have lifts.
It's not a new phenomena, when I started, boats that carried oxygen where a rarity. We took our own, we still do. Its been many years since you could (or should I say would), get on a boat that didn't have O2.
A couple of additional benefits of diver lifts have been the ability to pick divers up in more adverse conditions.
The biggest secondary benefit is how much easier it is to recover an injured diver. Just swim them on to the lift.