Your best bet is to take it off the trailer. It can be dangerous but with the right equipment and know how, it's possible. The boat needs to be lightened up first though. Whatever can be taken off should be, like the battery, fuel tank, engine, and etc.
I use four sailboat stands, one powerboat stand, many wood blocks, and a hydraulic jack with wheels on it.
I picked up two car stands in a yard sale several weeks ago and I plan on modifying them to be used for removing my boat from the trailer.
It's a tough task trying to take a keel/centerboard sloop off a flat bunk trailer. The way I do it is very time consuming.
Years ago when I had my boat on the roller trailer that came with the boat, it was so easy to get thay boat off it and on to stands. It was even easier and faster getting the trailer back under it. I could get that trailer back under it in just 20 minutes.
With my Long tandem flat bund trailer it takes a good part of the day to get it off or put it back on. Like I mentioned previously though, it can be dangerous.
I've learned a few simple tricks for getting the trailer's keel board lined up with the keel after the trailer is back under the boat by using the jack's wheels to slide the trailer over an inch or two. By placing the jack on a plank under the trailer's axle and using a block&tackle to move the trailer sideways to get it to line up with the keel, the boat can be lowered on the trailer exactly as straight as when it was originally raised off it.
When I had my roller trailer I used to place four of my sailboat stands on the stern of the boat, two on each side close together and rope off my boat's stern to a tree in the yard with a set of blocks in between to tweak it if I had to. Then I'd use my truck to pull the trailer out from under the boat, ever so slowly.
When the keel got pass the back of the trailer, I'd shore up under it with wood blocks, and pull the trailer completely out from under the boat.
To get the trailer back under it, I'd line the trailer up with the bow and winch the trailer under the hull without the truck. I'd place a plank under my tongue jack roller to make it easy for the trailer's tongue jack to roll and not dig into the dirt. I still use a plank under the tongue jack on the Long tandem flat bunk trailer.
With this trailer, I use my hydraulic jack and my straight powerboat stand to raise the bow of my boat and move the trailer ahead a little at a time by using a set of blocks attached to my truck. We're talking about 12" to 15" at a time between the trailer's cross members, and then move the stand to get another bite and gain more ground each time until the trailer is out from under the boat.
The ideal scenario is to be able to support the bow of the boat with something like a gantry or an eye beam which could allow the trailer to be completely moved right out from under the boat.
I know of a guy in my area who built a long wooden beam using 2"x6" planks, lags, and Gorilla Glue to get his trailer out from under his 73 O'Day 23.
Talk about beams. This old guy down the road gave away to narrow long metal eye beams to one of his friends. Man, I'd have given him $20 for one of them. I'd use it to suspend the bow of my boat. What a time/work saver that would be, for me.
Another guy used a gantry that he built to hold the bow of his MacGregor. That one can be Googled.
I tell you these things Todd to stimulate your brain a little but as far as attempting it goes, only you can make the call. Some guys don't feel comfortable doing stuff like this and it is completely understandable because it can be dangerous.
I was a power company lineman for many years and we were constantly dealing with heavy equipment and weighted objects. I also have a son who used to do rigging and he had to deal with heavier weights than I did.
Right now my boat is on stands and if anything ever happened to me and my boy needed to get it back on the trailer, I'm certain that he could do it with no problem even though he's never done it or helped me do it.
Hey if I croak they can do whatever they want with the boat. I won't need it and let's face it, ya can't take it with you.
