How do you switch two fiber glass boats from one trailer to another?

unless you have a boat lift or forklift designed for boats they need to be swapped in the water or you could damage the hulls.

The only thing I can think of would be a hoist, with tie-down straps that can hold at least 1800 pounds.

Call auto repair places, they might be able to think of something.

Good luck.

It can be done the way Richard D says. I have done it several times. The problem is that it can be very tricky and dangerous. You are right that they are too heavy to put on the ground. Lift them off and put them on boat stands. You need at least 2 heavy duty jacks, at least 4 boat stand and boards long enough to clear the width of the trailer and strong enough to hold the boat. Lift the boat off the trailer EVENLY using the adjustable boat stands which you placed so that there will be room to move the trailer forward. Lift it high enough to completely clear the trailer as it moves forward. Remember if they are wood cradles they are probably warped so account for that in the height. You can slide the board under the bow and raise it using jacks and then resting it on solid wood chocks that will be more stable than the jacks. be sure to clear the wheels. This board is not a 2x4 and don't use several small pieces, they will break. Use a nice solid piece like they have on scaffolds. Once the boat is resting on the stands and board slowly move the trailer forward you will need to remove and replace boat stands as the trailer moves and it's struts reach the existing boat stands. Remember to keep the boat evenly balanced. It is a slow process but it works and we have moved boats over 4000 lbs. without incident.

I would take both boats and trailers to the local marine dealer if this is possible. Here's how you do it. Go to the U-haul store and rent a car trailer or borrow a platform trailer from a friend that will hold the broken trailer. Load the broken trailer up onto the platform trailer. This may take some skids and a come-along winch. Then take the two to a local marine shop that has a boat forklift to make the switch for you. It is possible to use the jack method, but be careful to have a stable footings for your jacks as well as stable jack-point on the boat. I'd sure hate to see you destroy your good boat.