If your cabin lacks a hatch overhead, it’s easy to add one from a company such as Bomar, Lewmar, Taylor Made or Vetus. Hatches come in a wide range of sizes and shapes. For this project, we use the rectangular Lewmar Low-Profile size 30, which measures overall 153⁄8 inches long by 20¾ inches wide and requires a minimum deck thickness of five-eighths inch. It has friction hinges (with adjustable tension) that hold the hatch open without the need for gas-assist struts. When unlocked, it can also be latched or unlatched from outside and inside.