i've found the cockpit accessable icebox and the sink are a good places to stow beverages during a tack. A-231 also has a winch handle holder on the forward side of the cockpit that will hold some smaller water bottles.

i can't remember who's done it, but i recall one of the Ariel rehabs included moulded in drink holders in the cockpit. I bet Moderator Bill or Ebb will remember the link....