Yes, this is essential. Virtually all the weight should be borne by the blocks under the keel. The jackstands are only to keep the boat from tipping to one side or the other. With a relatively thin-hulled boat like a Montgomery, putting too much weight on the jackstands is likely to cause gelcoat cracks. -----Original Message----- From: Kearns, Kevin P Sent: Sunday, April 20, 2014 10:05 AM To: For and about Montgomery Sailboats Subject: M_Boats: Jack stands All, Next week I'm putting my M15 on jack stands for a few days to touch up the bottom paint. Does the bottom of the keel need to be supported on a block while on the jack stands? The marina that is helping me caters to power boats, not sailors so they will not likely be much help. Thanks, Kevin