tires
Done it a few times, drop the tongue as far as possible, some boats you need to put the trailer wheels on something, a few 4x4's or something, block the stern up where it is now with a couple inflated tires with a rimless tire on top of them, throw an old blanket on top of the last tire to avoid any potential black marks, then raise the toungue higher than normall, that will normally give you plenty of work room between boat and trailer, when dry reverse the procedure to set it back down. to do the bow, rasie the tounge as high as possible, block the bow up and let the tongue back down till you have room to work. If you want the trailer completely out from under the boat, raise and block the stern, then raise the bow high, and block that up, slide the trailer ahead as far as possible, leapfrog any crossmembers as you come to them. IF it is a light boat, you can raise it up as 'normal', then tie it to the rafters with 2" tow straps (not the springy snatch straps) and block it as needed. Once had 3 boats hanging from the rafters in my pole barn, a 19ft I/O, a 21ft twin outboard, and a small 14ft runabout, (along with my little o'day sprite that lived on the wall) they all needed some bottom work and to be painted, figured I'd spray them all at once and save some clean up time. got some strange looks when people walked by the door. If you hang the boat, get some wide off road type tires to have under it with you when working to limit any fall distance if something lets go.Ken