A cat-ketch is a sailboat that is rigged as both a catboat and a ketch. Specifically, there is larger mast stepped at the very bow, and a smaller mast further aft. It is different from a standard ketch rig because there is no jib, and the foremost mast is further forward than most ketches. This rig is found on amongst others Sharpies, Sea Pearl 21, Freedom Yachts and Wyliecats.
References
Cat-ketch Wikipedia(Text) CC BY-SA