What does “slip” mean?
GRACE: When is she gonna come up for air? And she's-- I mean, my God! Oh, Anastasia, this is the best gift you've ever given me!
KAREN: Don't kid yourself, honey. I didn't do it for you. Helena took our slip at the yacht club, and, uh...drilling a hole in the bottom of her boat just didn't turn my crank the way I thought it would. [BEAT] It is amazing how long Rosario can stay underwater, though.
What does “our slip” mean? Is it uncountable noun?
What did Helena do to Karen?