Lewmar Size 18 Low Profile Hatch Flange Base
Lewmar Size 18 Low Profile Hatch Flange Base — Product description
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.
Ventilation Master
Generous opening floods cabins with fresh air, combating humidity buildup.
Low Maintenance
Self-supporting arms mean fewer parts to fail, more time on the water.
Frequently Asked Questions
What makes the Lewmar Size 18 Low Profile Hatch self-supporting?
Integrated friction arms hold the hatch open at any angle up to 90 degrees without additional supports, simplifying use on deck.
Is the smoke grey acrylic suitable for harsh marine environments?
Yes, the 5/16-inch thick smoke grey acrylic provides UV resistance and impact strength, preventing yellowing and cracks from sun and salt exposure.
What is the exact cut-out size required for installation?
The hatch requires a precise 16 9/16-inch diameter cut-out for a flush, professional fit.
How do I ensure a watertight seal during mounting?
Apply marine-grade sealant to the flange base and torque fasteners evenly. Fit to surfaces within +/- 1mm flatness for optimal performance.
What fasteners should I use for the hinges and frame?
Use M6 (1/4-inch) for hinges and 5mm CSK No.10 UNC or 2 BA screws for the lower frame, backing into solid core material.
Why is the low-profile design beneficial for boats?
The 1-inch height minimizes wind catch and deck clutter, improving safety and aesthetics on sleek vessels.
Can this hatch handle heavy weather conditions?
Absolutely—its sturdy construction and secure locking make it reliable in high winds and waves, with a proven track record in offshore cruising.
| Support System | Lower Frame (in) | Acrylic Colour | Hatch Weight (lb) | Acrylic Window Thickness (in) |
| Self Supporting | 9/16 | Smoke Grey | 4.9 | 5/16 |
Dimensions
| 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 |
Mounting Instructions
Fit to a flat surface with a maximum tolerance of +/- 1mm. Fastening size at hinge section use M6 (1/4"). Fastening size for lower frame use 5mm CSK screw No.10 UNC 2 BA.
SKU: NVN-1002626
MPN: 39918030
UPC: 743683107061
Technical specifications
| Brand | Lewmar |
| Model | Lewmar Size 18 Low Profile Hatch Flange Base |
| SKU / MFR# | 1002626 |
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Frequently asked questions
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