look here: Catamaran Haul-out shipyards
Yacht Basin does 30' beam and its fairly near the C&D canal. They are expensive. Pleasure Cove is a bit north of Annapolis
, and can handle almost 24'. They are 10 minutes from BWI airport
, if that matters.
Twenty foot beams are a bit better off: Gingerville Marina on the South River and Herrington Harbor North are in Edgewater and Deale Maryland respectively. There is a pretty creaky old crane with spreader bars at Hartge's on Back Creek in Annapolis.