I had a long canvas curtain made that was held temporarily in place by a series of press studs fitted around the perimeter of the curtain and around the inside of the metal trim around the companionway hatch and door. During the day time it was rolled up and put away, and just fitted in place at night for privacy. This covered the entire hatch and companionway, and arguably also helped to retain some of the heat from the Ebberspacher diesel heater during the cold winter nights.