Jon, Unless there are spreaders between the ends of the fore and aft straps you are still exerting excess loading at the hull deck joint. There should be spreader(s) at the ends of the straps running athwartships,or a similar structure, to prevent the straps from compressing the hull and deck. fortunately the M-15 and 17 are relatively small light boats. Good Luck.have fUn. GO On Sat, Mar 26, 2022 at 12:23 PM Jon Barber <brbrbarber@gmail.com> wrote:
I found this drawing online. It is for a 17. I would use a piece of 4x6 df with thru bolted eyes, one on each end and one on the opposite side in the middle. It should be a bit shorter than the length of the keel. Hang it from the crane and use 3" wide ratchet straps, one in front and one in back of the keel. You can rig it and then use the ratchets to adjust the load. I think the straps are rated at 1650# each, so they are over kill. That's OK. Lifting my boat I want over kill!
I have never done this! Use at your own risk!
Jon Barber Monty17 Ol'44