Lewmar 19-18" Square Ocean Hatch. Engineered for serious offshore use, delivering exceptional strength, safety, and watertight performance in demanding conditions. Designed for blue-water cruising, its robust construction and purposeful deck profile provide confidence and reliability at sea. Manufactured from solid marine-grade aluminum with a thick acrylic lid, the hatch is built to withstand heavy loads, green water, and prolonged exposure to harsh marine environments. A trusted choice for offshore yachts and professional builds, backed by Lewmar's proven ocean-going heritage. 16-3/8" X 16-3/8" cutout.