Discover the Sleek Performance of the Lewmar Size 18 Low Profile Hatch
Engineered for modern boats and yachts, this low-profile hatch delivers exceptional ventilation and natural light without compromising your vessel’s streamlined deck aesthetics. Its flange base design ensures a secure, watertight seal, making it ideal for cabins, heads, or anywhere you need reliable overhead access. With a lightweight build at just 4.9 lbs, it reduces top-heavy stress on your boat, enhancing stability during rough seas.
The smoke grey acrylic pane offers subtle UV protection while maintaining clear visibility, resisting yellowing and cracking over years of exposure. Self-supporting for effortless operation, it opens smoothly up to 90 degrees, locking securely in place—no extra braces needed.
Precise Specifications for Seamless Integration
Support System
Lower Frame (in)
Acrylic Colour
Hatch Weight (lb)
Acrylic Window Thickness (in)
Self Supporting
9/16
Smoke Grey
4.9
5/16
Diameter (in)
Height Z (in)
Hinge Length HX (in)
Hinge Width HY (in)
Cut-Out Diameter (in)
19 15/16
1
19 7/16
5 9/16
16 9/16
Effortless Installation for Lasting Durability
Designed for flat deck surfaces with up to +/- 1mm tolerance, this hatch mounts quickly using standard hardware. Secure the hinge section with M6 (1/4″) fasteners and the lower frame with 5mm CSK screws (No.10 UNC or 2 BA). Always bed the flange with a marine sealant like polysulfide or polyurethane for a bombproof seal against leaks.
Prep Tip: Measure your cut-out precisely at 16 9/16 inches to avoid trimming hassles.
Pro Advice: Align hinges parallel to the centerline for even opening and minimal wind resistance.
Maintenance Hack: Annually inspect seals and lubricate hinges with Teflon-based grease to keep operation whisper-quiet.
Boat owners rave about how this low-profile design eliminates snags from sheets or feet, perfect for performance-oriented setups.
Why Boaters Choose This Low Profile Hatch
Beyond specs, it’s the thoughtful engineering that shines. The ultra-slim 1-inch height hugs the deck, slashing windage and drag—crucial for racing or long passages. Smoke grey tint cuts glare without blocking light, ideal for chart tables or sleeping quarters. Its robust acrylic withstands hail-like impacts, backed by Lewmar’s reputation for marine-grade toughness.
Lightweight Champion
At 4.9 lbs, it won’t throw off your trim, letting you focus on the sail.
