In searching for leaks and testing to see if I got them all, I've had to raise and lower the tub a few times. Trying to get my kids over to help has been like pulling teeth. I got them over once and four of us were able to raise it up and lower it. Then I found another leak and the kids found themselves busy.
Trying to devise a way to do it myself, I looked around to see what I had. I had some sailing gear with cam cleats, 4-bolt eye pads, and deck cleats. I had an old pulley set that needed a new rope but I had some rope from the boat I could use. And there was a 12-foot 4x4 under the deck that was never used when building the deck.
I made up some stops as a safety factor and screwed them to the 4x4. I built an attachment for the spa that would double as a guide and point to which to attach one of the 4-bolt eye pads. The other pad I screwed to the top of the 4x4. A trial run told me I needed to hinge the 4x4 at the bottom. I screwed that to the deck. I installed both the cam cleat and the deck cleat to the 4x4 at a point that would allow me to pull the pulley line down from above, that way I could apply more of my weight. As it turned out, the beginning of the lift required me to make loops in the line to place my foot in and free my hands to help lift up as my foot pushed down. That made it much easier.
It worked out very well but it required all I had at the beginning of the lift. I'm afraid I wasn't kind to my kids as I reached the brink of exhaustion tugging on that rope and some expletives may have passed my lips.
Once it was about half way up, I could just pull down on the pulley line with one hand. On the way back down, I turned the stops 180 degrees one at a time and it came down easily. That was an unintended design factor (luck) that worked out great.
Here's some pics:
