Winterizing Contessa 26

I intend to keep my Contessa 26 afloat, in Cherbourg marina, during next winter.
As mentioned in winterizing guide I found on the internet, I closed all thru-hulls seacocks, except for cockpit drain. Being below the waterline, I'm afraid if freezing, the cockpit drain hose could be broken and the boat could sink. What do you think?
Yours advices  would be well appreciated.
Thank you.