Round Inspection Hatches (White) – 4″ / 6″ / 8″

These round inspection hatches are designed to provide reliable and convenient access to various areas of a boat – bilges, lockers, fuel or water tanks, instrument panels, steering systems, etc. They are made from high-quality plastic (ASA or ABS) in white color, which is UV-resistant and built to withstand harsh marine conditions. This means the hatches won’t yellow or become brittle even after prolonged sun exposure, and their smooth surface is easy to clean of salt and grime.

They come in three standard sizes:

• 4 inch (small) – Flange outer diameter ~143 mm, cut-out (hole size) ~101 mm. Best suited for compact openings where access is needed for small items or visual inspections – for example, checking a fuel filter, reaching a pump or sensor, or access ports on the transom of an inflatable boat. Recommended for small boats and tight spaces.
• 6 inch (medium) – Flange outer diameter ~198 mm, cut-out ~152 mm. This is the most common, all-purpose size, providing an opening large enough for a hand and forearm. Ideal for inspecting a bilge pump, accessing seacocks and valves, electrical connections, or dry storage compartments. Suitable for most motorboats and sailboats as a standard inspection port.
• 8 inch (large) – Flange outer diameter ~250 mm, cut-out ~203 mm. The large opening allows two hands in or the removal/insertion of bulkier components (e.g., a battery, small water tank, or reaching deep into the hull for repairs). Recommended for bigger yachts, deck access hatches, or areas where a wider entry is needed.

All sizes share the same design – a round, screw-type (bayonet twist) lid. The lid locks/unlocks with about a quarter to half turn to open or close securely. On the underside of the lid is an integrated rubber O-ring gasket that presses against the base to create a watertight seal. This keeps out rain, spray, and wash water from entering the compartment below. For optimal performance, the gasket can be periodically lubricated with silicone grease to remain pliable and effective.

The flange (frame) of each hatch has pre-drilled countersunk holes (typically 5 to 8 holes evenly spaced). Installation requires cutting a circular hole in the mounting surface to the appropriate diameter, inserting the flange, and fixing it in place with stainless steel screws. It’s recommended to use a suitable sealant (marine silicone or polyurethane) between the flange and the mounting surface during installation for a completely watertight result. Once installed, the hatch has a low profile – it protrudes only slightly above the surface with a smooth, rounded edge, so there’s minimal risk of tripping or snagging lines/gear on it. The construction is sturdy, allowing the closed hatch to be stepped on without damage (within normal use).

Ease of use: Each lid features a textured top surface to prevent slipping when wet. To open, the design includes either a recessed hand grip (two half-moon indentations to insert your fingers) or a slot for a flat key/coin – depending on the model. In both cases, you can easily twist the hatch open by hand without needing tools, yet it stays firmly in place when closed and won’t loosen due to vibrations.

Applications: These inspection hatches are widely used on decks, cockpits, transoms, seat boxes, and consoles – anywhere that requires periodic service or access but not a permanently open hole. They are also great for sealing off apertures made for equipment installation (e.g., running cables or pipes) while retaining future access. The white color blends aesthetically with most boats and reflects sunlight (so it doesn’t get overly hot).

With these inspection ports, you maintain the clean look of your boat by concealing maintenance access points behind neat covers, while ensuring quick entry for repairs or inspections whenever needed. The product combines the functionality and style required for modern marine outfitting.