Dan, I did what you are thinking about. I made some adjustable legs but you can use a bunch of 8 inch concrete blocks and a couple of 8 foot 4x6 cross beams, all available at Lowes or Home Depot. My local store also has 6x6 inch beams but that seems like overkill. Anyway, I lifted first the aft keel with a cylinder jack and blocked it up, then put the jack under the nose of the cb housing and slid the second timber under the keel right in front of the cb housing where it joins the hull. By alternating jacking and blocking with 8 inch clocks with 2x4 blocks on top of them so you didn't have to jack a full 8 inches every time, you can work the boat up off the trailer. By placing wedges on the top of the cross beams you can brace the hull upright on the crossbeams. End up with some solid blocking that just catches the fore end of the cb housing. There is about 4 inches of housing forward of the cb slot for a secure insurance blocking. Be sure to keep the whole cb slot clear with your final blocking. Or you can slide the boat aft on the trailer, after blocking up the back end of the trailer frame, and once the cb clears any cross members on the trailer you can dig a hole under the trailer and drop the board into it. That way the boat stays on the bunkboards of the trailer the whole time. By digging the hole with a slope on one side you can then tip the board to that side and haul it out of the hole. Reverse the procedure to put the board back. I did this with my first M 17 back in 1983. Good luck. Tom B, M 17 #258, 77'