Butt Hinges

When it comes to boat hinges, there are different kinds to fit every application. Some hinges are built to secure a specific door material, like glass door hinges. Other hinges are built to distribute a heavy load along the entire length of the mounting material, like piano hinges. Concealed hinges offer a hidden mounting option for cabinets and interior design.

For more specific uses, specialty hinges supply everything from transom door replacements to quick-release Bimini tops. Out of all of these hinges, butt hinges are the most common. Since they come in so many types, materials, and mounting styles, they can be useful in many aspects of boat construction.

Butt hinges are hinges that attach to the abutting surfaces of a door jamb — or of a deck and a hatch. They are typically short — less than 5” — are used in sets of two or more, as opposed to a singular hinge. The basic design consists of two plates joined together by a hinge in the middle. On boats, the butt hinge is most commonly used for hatches, lockers, and livewell covers.

Within the category of butt hinges, there are different types for different applications. The standard hinge offers standard open and close features with nothing extra built into it. Other butt hinges are built for a more specific function.

Friction hinges are built to resist pivoting in one direction. In the marine world, this can eliminate the need for gas shocks or hatch springs. Instead of needing a shock to hold a hatch open, the friction hinge holds it open for you.

Take-a-part hinges are built with ease of removability in mind. When necessary, these hinges pull apart with ease. This can be useful for work access points, privacy doors, and light-duty transom doors.

Double-knuckle hinges are built to allow hatches to open a full 180 degrees and lay flat on the deck when both opened and closed. This allows you to have complete access to any hatchway unimpeded by the hatch cover.

Butt hinges are made in a variety of materials. In the marine world, stainless steel is by far the most common. Non-stainless steel should be avoided at all costs as it will corrode and fail when subjected to marine use.

Plastic provides an effective substitute to stainless for light-duty applications. It is lightweight and completely rust-proof.

For medium-duty applications, zinc alloy hinges can be an alternative to some stainless steel hardware. Zinc is corrosion-resistant, durable, and cost-efficient; however, it is not as strong as stainless. In raw form, zinc is not nearly as attractive as stainless, but when powder coated it can be aesthetically pleasing.

Bronze is another metal that can be used in marine hinges. Bronze, although very strong, is not as strong as stainless. Bronze is a softer metal that will bend but not break. If left natural, bronze will develop a patina on its surface unlike stainless, which will stay shiny with minimal upkeep. For hardware above the waterline, stainless has become the clear favorite in the boating industry.

Even within the different hinge types, there are different mounting styles for different uses. The common top-mount hinge has its pin mounted above the mounting surface. This mounting style offers a wide range of motion for the hatch. Its drawback is that, because it creates a raised surface, it’s not desirable in high-traffic areas.

For high-traffic areas or just a cleaner-looking install, flush-mounted hinges have the pin mounted below the mounting surfaces. This creates a flush mounting surface, but in certain applications can limit how far the hinge might open. Additionally, flush-mount hinges typically can’t be retrofitted. Instead, specially tooled recesses are needed in the fiberglass deck and hatch.

Swaged mount hinges use a pin that is even with the mounting surface, keeping the deck clear of obstructions but still allowing hatches to open with a wide range of motion. Like flush mount hinges, swaged hinges may require specially tooled decks and/or hatches.

Most hinges only mount onto even and flat surfaces. Offset hatches are designed for uneven surfaces or hatches up against a bulkhead.

Butt hinges are simple, strong, and dependable, but they can only be as strong as the material you mount them into and what you mount them with. It is important that you pick the proper hardware for mounting your hinges. All screws or bolts should be marine-grade stainless, and any mounting holes should be properly sealed. Any unsealed hardware can allow water into the hull of your boat, compromising its coring.

On heavy surfaces or when using friction mounts, stainless self-tapping screws may not be able to bear the weight put on them. In these instances, it is important to properly through-bolt your hinge to avoid destroying your coring. An overloaded screw can strip out the coring it is mounted in.

Even stainless steel will corrode if not properly maintained. But remember, less is more with stainless. Never use abrasive cleaners or materials on stainless steel. Avoid cleaners that contain ammonia (window cleaning solutions, for example), chlorine (anything with bleach in it), or sulfur. All that’s really needed for routine maintenance of stainless is a quick wash with a mild soap such as Boat Wash.

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