Lewmar hatches are marine deck hatches built for ventilation, natural light, and deck access, sold in several profile families — Ocean (heavy-duty offshore), Medium and Low Profile (streamlined cruising), and Flush (lowest profile) — plus a full range of replacement lids, seals, and hinge kits. Choosing the right one comes down to matching the hatch size to your deck cut-out and the profile series to how and where you sail.
Lewmar hatches at a glance
| Series | Best for | Profile | Key trait |
|---|---|---|---|
| Ocean | Offshore cruising & commercial | Higher | Reinforced build, enhanced sealing; flange or flat base |
| Medium Profile | Cruising & performance yachts | Medium | Balances strength with a streamlined look |
| Low Profile | Modern decks, height-limited areas | Low | Sits close to the deck; friction-lever options |
| Flush | Sleek modern aesthetics | Lowest | Nearly level with the deck when closed |
What sizes do Lewmar hatches come in?
Lewmar hatch sizes refer to the deck cut-out the hatch requires, so the size number is really a fit specification. Common references include Size 70 at roughly 62.7 x 62.7 cm (24 11/16" x 24 11/16") for smaller vessels, galleys, and tight spaces; Size 77 at about 69.9 x 69.9 cm for increased airflow and light on mid-size boats; and Size 78 at around 72 x 77.0 cm (28 1/4" x 30 1/4"), the largest opening, suited to main salons, master cabins, and emergency egress. Lewmar also numbers smaller replacement components by size, from Size 00 hinge kits up through Size 60 lids. Always measure your existing opening — undersized cut-outs prevent installation, and oversized cuts compromise the deck structure.
How do the Ocean, Medium and Low Profile, and Flush series differ?
The Ocean series is Lewmar's heavy-duty option, engineered for offshore cruising and commercial use with reinforced construction and enhanced sealing. It comes in flange-base and flat-base configurations: the flange base sits on top of the deck for easier retrofit and superior drainage, while the flat base recesses for a lower, cleaner installation. Medium Profile hatches balance strength with a streamlined appearance and suit cruising and performance yachts, while Low Profile models sit closer to the deck and are often paired with a friction lever for controlled opening. Flush hatches sit nearly level with the deck for the sleekest look, trading some ventilation for that low profile.
What are Lewmar hatches made of, and how long do they last?
Lewmar hatches use marine-grade materials chosen for saltwater service. Frames are typically anodized aluminum or marine-grade polymer that resist corrosion and UV degradation, while lenses use tempered safety glass for clarity and impact resistance or high-grade acrylic where weight matters. Sealing relies on layered barriers — primary seals, drainage channels, and secondary weather seals — with 316 stainless steel or bronze hardware to prevent galvanic corrosion. Tropical, high-UV boats benefit from UV-resistant materials, while cold-weather use calls for seals that stay flexible at low temperatures.
Can I buy just replacement parts for my Lewmar hatch?
Yes. Rather than replacing a whole hatch, you can restore an existing one with genuine Lewmar spares — lid assemblies, seal kits, hinge kits, and friction levers all sold separately. Matching the exact series and size of your hatch base is essential for a proper fit and a watertight seal.
Frequently asked questions
What is the difference between Lewmar Ocean, Medium Profile, and Flush hatches?
Ocean is the heavy-duty offshore series with reinforced construction and enhanced sealing; Medium and Low Profile hatches trade some height for a streamlined cruising look; and Flush hatches sit nearly flat with the deck for the sleekest profile, with somewhat less ventilation.
How do I determine the correct Lewmar hatch size?
The size number is the deck cut-out dimension. Size 70 needs roughly 62.7 x 62.7 cm, Size 77 about 69.9 x 69.9 cm, and Size 78 around 72 x 77.0 cm. Measure your existing opening or your desired opening and match it to the size.
What is the difference between flange-base and flat-base Ocean hatches?
Flange-base hatches have a raised perimeter that sits on the deck for easier retrofit and a watertight seal, while flat-base models recess into the deck for a cleaner, lower-profile appearance.
Can I replace just the lid on my Lewmar hatch?
Yes — Lewmar sells lid assemblies (such as Low Profile Size 44 and Size 60 MKII lids) as standalone parts. Match the exact series and size of your existing base so the new lid seals correctly.
Why do same-size Lewmar hatches vary in price?
Price reflects the series, materials, and finish. Ocean models cost more for their heavy-duty offshore build, tinted (smoke) lenses differ from clear, and complete hatches cost more than lid-only or seal-kit spares.
Do Lewmar hatches keep insects out?
Many Lewmar hatches integrate insect screens so you can keep ventilation open at anchor without letting bugs in — a key feature for extended stays in tropical anchorages.