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Lewmar Hatch Range Identification

Updated: Jun 22, 2021

The ranges are;

  • Superhatch (obsolete - 1980-87)

  • Rollstop (obsolete - 1987-92)

  • Ocean (1992-)

  • Coastline (obsolete - 1991 - 2000)

  • Trimport (obsolete - 1991 - 2000)

  • Trimline (obsolete - 1988 - 2000)

  • Low Profile (1998-)

  • Medium Profile (1998-)

  • Flush 1G (obsolete - 2006 - 2010

  • Flush 2G (2010-)

  • Flush 3G (2013-)

In addition there may be some custom variants developed by Lewmar on a bespoke basis.

All Lewmar units produced after 1997 have a code hot-stamped into the acrylic which is helpful to date and determine the model/size/colour.

Hatches are typically distinguished by hinge design, stay type and frame section.

Remember that if considering refurbishment we can provide a temporary hatch to securely cover the opening using our Lids4Lend service, covered in this previous Blog Article. More details from the main menu above too.


The original heavy duty hatch whose evolution led to the Rollstop and current Ocean hatch. Hard wearing, solid and as strong as ever. We now stock new closing seal for these hatches. Characterised by strap type hinges which fasten through the acrylic. Note that hinge kits are no longer manufactured, so try not disassemble.


Very similar to Superhatch but without the strap hinge. Hinge uses a 'knuckle' mechanism to click/hold lid in position. On older hatches the 'click and stay' element may be long gone. Hinge kits are available from the US ( or occasionally on eBay etc. Again, best try and avoid having to disassemble the hinges. Hinge blocks are fastened to the base with screws/bolts. Size 30 and below also have rivets meaning you have to remove the whole hatch (including base), unless willing to drill out the rivets.


Still the King of high quality heavy duty deck hatches, suitable for foredeck use where lesser hatches (and Chinese copies) fail (ie leak). Uses pinned hinges and lid/acrylic mounted friction arms. Note that the Ocean has a finger grip pressed into the front edge of the lid frame.

We can supply new Ocean hatches with options for part exchange available.

Hinges feature pins which slide out. We can provide guidance instructions to help.


A lighter version of the Ocean, with thinner acrylic and best for offshore rather than ocean sailing. Has a similar hinge/arm to Ocean but can be distinguished by NOT having the finger grip in the lid frame (so front edge is constant). From the underside you will also see that the closing seal is separated from the acrylic by the frame section.

No longer available, these can be upgraded to Ocean for heavier duty.


A sort of halfway house between a Coastline hatch and portlight, commonly used on coachroof sections which are less vertical. Tend to be shorter and shallower like a portlight.

Do not have exterior handles.


Similar to Coastline but uses stays rather than friction arms to hold up the lid.

Designed more for power boats where increased pitching/pounding at speed could make friction arms fail causing lids to slam (hopefully without fingers or head in the way).

Low Profile

Similar to slightly heavier Medium Profile and introduced as a replacement for the Coastline and Trimline range, this has a rubber gasket as opposed to a sealant based seal around the acrylic lens. They have friction arms on the larger sizes. Smaller sizes, (particularly earlier versions) may use a friction mechanism within the hinges (which is often

secured with loctite 243 making removal more difficult).

The lid section of a LP hatch is 25mm deep and the inner frame profile can be angled or 90 degree depending on version.

There are two (actually three according to Lewmar, but no details on Mk 3) versions with the Mk2 in use from December 2000.

The difference is in the hinge and frame section, the former meaning that replacement lids must be specified as Mk1 or Mk 2. More details in this earlier Blog post. Because the frame section of later versions looks very similar to MP, the only safe way to differentiate is based on the lid height (thickness - 25mm vs 32mm) and/or the rubber seal section. For LP the width of the closing element (the part which sits against the base) is ~17mm, versus ~22mm for the MP seal. The photo to the right shows this with MP on the left, LP seal on the right.

Medium profile

Difficult to distinguish from LP from the outside, the MP was introduced as an alternative for the Lewmar heavier duty hatch (Ocean). Like the 928 as a intended replacement for the Porsche 911, some still prefer the Ocean as the original true heavyweight when the going gets tough. Easier and cheaper to produce does not necessarily make better...

The lid frame section is slightly (32 vs 25mm) deeper and the acrylic is typically 2mm thicker. The inner frame profile is 90 degree, rather than angled, but as mentioned above this alone is not definitive. There are two versions of the MP but parts are interchangeable so not important here.

Flush / Flush 2G

The closing seal is mounted in a rebate machined to the underside of the acrylic lid. This does unfortunately weaken the sides/corners and can lead to these breaking, particularly if a rope is trapped beneath. Flush hatches are supported using stays which are secured through the acrylic, with pads to the exterior.

The original flush (1G) has the hinge fittings bonded to the acrylic whilst the 2G has the hinges bolted through the acrylic. Handles are similar to Low/Medium Profile with curved exterior design.

Flush 3G

The closing seal is mounted to the lower frame, not the acrylic (which is thus of constant thickness). Handles are recessed and need a star key (or winch handle) to release from the outside

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