Lewmar Size 70 Ocean Series Hatch Flange Base
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Lewmar Size 70 Ocean Series Hatch Flange Base Product Description
Discover the Reliability of Lewmar Ocean Series Size 70 Hatch Flange Base
Engineered for demanding marine environments, the Lewmar Size 70 Ocean Series hatch flange base stands out as a robust foundation for your vessel's deck openings. This flange base, part of the renowned Ocean Series, supports large hatches ideal for main salons, engine rooms, or spacious cabins on yachts and offshore boats. Its design prioritizes seamless integration, weather resistance, and long-term performance, ensuring your boat stays dry and secure even in rough seas.
Crafted from high-grade materials, it accommodates acrylic panes in smoke grey tint, offering optimal UV protection while maintaining clear visibility. Boat owners appreciate its straightforward mounting on flat decks, making it a go-to for refits or new builds where durability meets elegance.
Standout Features for Marine Excellence
- Precision Fit: Mounts effortlessly on flat surfaces with up to 1mm tolerance, ensuring a watertight seal without custom adjustments.
- Versatile Fastening: Hinge area uses M6 or 1/4-inch bolts for rock-solid attachment; lower frame secures with 5mm countersunk screws, No.10 UNC, or 2 BA equivalents.
- Lightweight Yet Sturdy: Complete hatch assembly weighs just 23.8 lbs, balancing ease of handling with structural integrity.
- Thick Acrylic Glazing: 1/2-inch smoke grey acrylic provides superior impact resistance and glare reduction for safe, unobstructed views.
- 1-Inch Flange Design: Offers ample overlap for secure bedding and superior load distribution under wind and wave pressure.
Detailed Dimensions for Perfect Installation
Accurate measurements are crucial for hatch replacements or custom deck cutouts. Here's a breakdown tailored for boat builders and DIY marine enthusiasts:
| Spec | Measurement (inches) |
|---|---|
| Overall Length (X) | 27 5/16 |
| Overall Width (Y) | 27 5/16 |
| Height (Z) | 1 11/16 |
| Radii (R) | 3 |
| Hinge Length (HX) | 3/16 |
| Hinge Width (HY) | 19 3/16 |
| Cut-Out Length Flat (X1) | 24 1/2 |
| Cut-Out Width Flat (Y1) | 24 1/2 |
| Cut-Out Radii Flat (R1) | 1 11/16 |
Note: Verify deck flatness before cutting. Metric conversions available for international projects—roughly 694mm square overall.
Pro Tips for Seamless Installation
Installing the Lewmar Size 70 flange base transforms deck access. Start by marking the square cutout with 24 1/2-inch sides and 1 11/16-inch corner radii. Bed the flange with marine sealant like polysulfide for a drip-free seal. Torque hinges to spec, avoiding over-tightening that could stress the acrylic. Pair with Lewmar's ventilated Ocean hatch lid for airflow without leaks—perfect for tropical cruises.
Common pitfalls? Uneven decks—shim if needed within tolerance. For retrofits, this size suits many production cruisers from the 1980s onward.
Built to Withstand the Elements
The Ocean Series shines in its anodized aluminum construction, resisting saltwater corrosion better than powder-coated alternatives. Smoke grey acrylic blocks 99% UV rays, preventing interior fading. Tested for Category A ocean sailing, it handles slamming waves without flexing, a favorite among bluewater sailors for its no-fuss reliability over decades.
Maintenance Made Simple
Keep it performing like new: Annually inspect seals and hinges, lubricate with silicone grease, and polish acrylic with non-abrasive marine cleaner. Avoid petroleum-based products that haze the pane. This low-maintenance design saves time during haul-outs, letting you focus on sailing.
Why Marine Pros Trust Lewmar Size 70
Beyond specs, it's the proven track record. From transatlantic races to liveaboard adventures, this hatch base delivers quiet operation, easy venting, and unmatched safety. Upgrade your boat's deck without compromising style or strength.
Frequently Asked Questions
What surface preparation is needed for the Lewmar Size 70 Ocean hatch flange base?
Ensure the deck is flat within +/-1mm tolerance. Clean thoroughly and apply sealant for a watertight bond.
What fasteners should I use for installation?
Hinge section: M6 or 1/4-inch bolts. Lower frame: 5mm CSK screws, No.10 UNC, or 2 BA. Use stainless steel for corrosion resistance.
Is this flange base compatible with older Ocean Series hatches?
Yes, it's designed as a direct replacement for Size 70 models, maintaining the same cutout and mounting pattern.
How thick is the acrylic in this hatch setup?
The smoke grey acrylic window measures 1/2 inch thick, providing excellent strength and UV protection.
What's the total weight of the assembled hatch?
The complete Size 70 hatch with this flange weighs 23.8 lbs, making it manageable for solo installation.
Can this handle offshore conditions?
Absolutely—rated for ocean-going yachts, with robust construction to resist slamming and spray.
What cutout size do I need for the deck?
Flat cutout: 24 1/2 inches by 24 1/2 inches, with 1 11/16-inch radii at corners for a precise fit.
- 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.
| Lower Frame (in) | Acrylic Colour | Hatch Weight (lb) | Acrylic Window Thickness (in) |
| 1" Flange | Smoke Grey | 23.8 | 1/2 |
Dimensions
| Length X (in) | Width Y (in) | Height Z (in) | Radii R (in) | Hinge Length HX (in) | Hinge Width HY (in) | Cut-Out Length Flat X1 (in) | Cut-Out Width Flat Y1 (in) | Cut-Out Radii Flat R1 (in) |
| 27 5/16 | 27 5/16 | 1 11/16 | 3 | 3/16 | 19 3/16 | 24 1/2 | 24 1/2 | 1 11/16 |
"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."
Frequently Asked Questions (FAQ) About Lewmar Size 70 Ocean Series Hatch Flange Base
Who is the Lewmar?How to describe Lewmar Size 70 Ocean Series Hatch Flange Base?
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Who is the Lewmar?
How to describe Lewmar Size 70 Ocean Series Hatch Flange Base?
What is the highlights of Lewmar Size 70 Ocean Series Hatch Flange Base?
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Lewmar Size 70 Ocean Series Hatch Flange Base Technical Specifications
| Type: | |
|---|---|
| Vendor: |
Lewmar |
| Weight: |
26.0 lb |
Lewmar Size 70 Ocean Series Hatch Flange Base User Reviews
Lewmar Size 70 Ocean Series Hatch Flange Base Shipping & Return
| Shipping Weight: |
26.0 lb |
|---|---|
| Box Sizes: |
1.00 (h) x 1.00 (w) x 1.00 (l) |
| Cubic Feet: |
1.0 |
| Returnable: |
Yes |
| USPS First Class: |
Yes |
| P65: |
Yes |
| Truck Delivery: |
Yes |
For detailed shipping policy please check our Shipping Policy and you can find our Return and Refund Policy here.



