One of the biggest factors is why Belle was so inexpensive was the lack of a trailer. For small and old boats, the trailers and engines are typically worth far more than the boat. In fact, we sourced our trailer from a man who capitalizes on just that. Keith Moulton of KM Boat Salvage in Plaistow will happily take your old eye-sore away if it has a decent trailer and or motor. Keith often removes the engines and any other valuable bits from the boats and then has them crushed and disposed of. He then sells the trailers to folks like me who have a nice boat in need of transportation. So in order to buy the boat, I would have to sort out moving a sailboat from stands to a trailer.
Belle was sitting on a nice set of jack stands when we found her. She was stable and well supported with five jacks. Two at the rear and two near the front of the keel where the hull begins to narrow and a fifth at the bow on the centerline.

Moving a Sailboat from Stands to a Trailer is no small feat. so, I did what any self-respecting do-it-yourselfer does and googled other folks who had solved the same problem. I found a gentleman from Jamestown Distributing showing a powerboat being moved from trailer to jacks using a pair of bottle jacks and a pile of blocks. He placed two jacks under the transom and then lifted the front of the boat with a single bottle jack under the keel forward of the center of gravity. As he withdrew the trailer, he leap-frogged another bottle jack over each cross member as the trailer was extracted. This looked simple enough but with 1200lbs of lead in the keel, I bet Belle is a bit heavier.

I opted to gain another factor of safety in the process by implementing a sling. I saw some commercial portable slings online but the cost was prohibitive. I found a dimensional lumber column strength calculator online and plugged in the criticals to give me a column that would hold up the whole boat. This way, if we were off-center or something went a little wrong we would have plenty of margin.

I strung a 2X10 across the two triple-stack columns with big D rings, each rated to hold the entire boat. I then bought a pair of heavy-duty ratchet straps, again rated for the whole boat, to lift the hull up on the gantry.
Moving day came with good weather and a good brother. Dan and I pulled the modified trailer I made over and got things set up. We took a time-lapse of the process you can see above. The whole process took about 3 hours with the previous owner looking on with curiosity. He said we made it look easy.
Step one was to line up the trailer and unload the gantry. We then lifted Belle using her jacks high enough that the keel would clear the cross members of the trailer when we backed it under. I also added blocks and shims under the keel with a pair of bottle jacks as well.
With the gantry assembled and leveled just in front of the keel, we pulled the boat up off the forward jacks with the two ratchet-straps and snugged the bottle jacks up under the keel. With the weight off of the forward three jacks, we removed them and removed the bunks from the trailer for added clearance.

The next step was to slowly move the trailer back under the boat, leapfrogging the bottle jacks around the cross members as they passed by until the axle was just behind where we guessed the center of gravity to be. We looked at a lot of photos of O’Day sailboats on trailers to get a feel for this as it is critical, especially with a single axle trailer.
Once we were happy with the trailer location, we put the jacks back under for security. It was now time to install the bunks and snug them up to the bottom of the hull. We had to raise and lower the hull with the jacks quite a bit to get it level with the trailer. The middle bunk brackets were a bit tall and I had to drill holes for the u-bolts in order for them to lower enough. We then tightened all the fasteners and double-checked our work.
It was crunch time, hopefully not literally. We removed the slings and set the boat on trailer by un-screwing the jack stands all at once. Slowly lowering the boat down and loading up the trailer was a little nerve-wracking. However, it went very smoothly and the boat sat firmly on the trailer without fuss.
We disassembled the gantry and loaded it into the truck and put all the tools and accessories in the truck or boat. The mast was put back onto the trailer rests and secured down and the boat was strapped down to the trailer as well for the short ride home.

The ride home was uneventful. We made it back to the house without incident, checking the trailer hub temperatures about halfway. Once home, we were able to complete the trailer adaptations with the boat in place. I adjusted the position of the boat on the trailer now that I had more level ground by lifting the boat back up on the jacks and leveling the trailer underneath her. With the trailer level and centered, I then leveled the hull with the jack stands. I was now able to make the final bunk bracket adjustments and set the boat back down square.

The bow rest and winch post could now be constructed. I had ordered a length of 3″X3″ galvanized tube for this. Using a strip of luan plywood as a template, I clamped the luan to the brackets that the old winch post was secured to. With the bow rest also clamped to the plywood, the lengths and drill holes were laid out on the plywood to transfer to the galvanized tube. I then used a grinder with cut-off disk to cut out some of the top of the winch post to accommodate the bow rest and also make a pass-through for the winch cable. I wanted the winch to stay down low where we could easily reach it so I used a cable sheave that I bought at Tractor Supply Co. to change the direction of the cable at the top of the winch post. This sheave has no fairlead so you have to pay attention when your loading the boat to make sure the cable is on the sheave. This may be a future improvement opportunity.

With the winch post painted silver to try and protect where I had cut it, I mounted it to the trailer and bolted the winch, sheave, safety chain, and bow rest in place.
I don’t think I would recommend anyone try moving a sailboat from stands to a trailer by themselves. We took a lot of risks here. We have engineering degrees and experience with boats and trailers and still felt very uncomfortable the whole time the boat was being transferred despite how easy it looks.