A polycarbonate yacht hatch lens is the part of the deck that a crew member stands on, a passenger sits against and the sea hits. Glass is clearer and it is the wrong material for all three.
A yacht refit yard in Falmouth replaced six hatch lenses on a 12 m cruising yacht. Within two seasons, three leaked at the aft edge, all of them on hatches where the lens had been bedded on a 3 mm neoprene strip that had compressed to 1 mm.
Polycarbonate yacht hatch lens thickness
- Hatch to 500 x 500 mm: 8 mm
- Larger opening hatch: 10 mm
- Walk-on deck lens: 12 mm minimum
- Lens edge: 15 mm flat land for the gasket
The flat land is what the gasket presses against. A lens polished right to the edge leaves nothing to seal on, and the seal then depends on the frame clamping the curved face, which never holds over a season of thermal cycling.
Gaskets, hinges and UV
A 12 mm EPDM gasket compressed by 25 percent gives a seal that tolerates movement. A thin strip gives a seal that survives the first tightening and fails after a summer. Hinges must be bolted to the frame, not into the lens.
UV is the marine reality. Deck lenses sit in full sun and salt, and an uncoated polycarbonate yellows within two to three years. A UV co-extruded or hard-coated lens holds clarity through a decade of service, and the difference is visible as soon as two hatches sit side by side.
Salt removal with fresh water is safe; solvent deck cleaners are not. Rinse after every passage and avoid anything with a ketone or an aromatic solvent in it.
Where the yacht also has a windshield or a hard top, the material logic overlaps with polycarbonate boat windshields, and the coating options are in UV resistant polycarbonate sheet.
Send your hatch frame drawing, lens size and sea area to oversales@rpplexiglass.com for a lens quotation.
Frequently Asked Questions
What thickness polycarbonate for a yacht hatch lens?
8 mm for hatches up to 500 x 500 mm, 10 to 12 mm for larger opening hatches or where the lens is walked on. Deck impact and foot traffic set the thickness.
Why do hatch lenses leak after a season?
Gasket compression and thermal cycling. A hatch lens clamped on a thin gasket loses compression as the frame and the panel move at different rates. A wider gasket with a defined compression is the fix.
Can polycarbonate hatches be walked on?
An 8 mm lens on a 400 mm opening takes a foot load with deflection; 12 mm on a 600 mm opening is the practical minimum. A lens spanning a large opening without a frame support will oil-can underfoot.