Hull profile on DS1

[jmj.2005]

I have a 1966 DS1 and store it on a trailer. The bunks are 6" wide covered by carpet and run around 6' along the bottom of the boat just outside of the stringers on the inside of the boat. When the boat is sitting on the trailer the hull looks like it deforms slightly (maybe 1" across a 1' section). If I step in the boat on the trailer it (of course) deforms more. Is this normal?
Also I haven't done it yet, but I plan on flipping the boat over to fix some poor repairs on the hull. Any suggestions on a safe way to do this?
Thanks, Jonathan