A polycarbonate boat windshield wins on one property that no other transparent plastic matches: it bends rather than breaks. On a boat, that difference is measured in boarding passengers, fenders and bow spray rather than in datasheets.
A RIB builder in Southampton fitted 8 mm polycarbonate screens to 60 boats. The screens that came back were not cracked; they had crazed at the fixing holes, because the panels were bolted through a tight frame with no clearance.
Polycarbonate boat windshield thickness and curvature
- Consoles to 6 m: 6 mm, gentle single curvature
- 6 to 9 m: 8 mm, heat formed to the console profile
- Offshore and commercial: 10 mm, formed and annealed
- Radius: keep above 300 mm on 8 mm sheet to avoid forced stress
Curvature is a forming decision. A radius above roughly 300 mm on 8 mm sheet can be achieved by heat forming with a simple mould. Tighter radii need vacuum forming and a matched mould, and the part has to be annealed afterwards.
Fixing detail: clearance, bedding and sealant
The fixing is where marine screens fail. Holes must be 2 mm larger than the fastener, the panel must sit on an EPDM or neoprene bedding strip, and the frame must not clamp the sheet hard. A screen bolted tight will craze in the first hot season.
Sealant should be neutral cure and marine grade. Acid-cure silicone attacks polycarbonate and leaves a crazed halo that cannot be polished out. Where the screen meets a painted surface, use a bedding compound that stays flexible.
UV and salt are the long-term pressures. Standard polycarbonate needs a UV co-extrusion or a hard coat, or it yellows within a few years in strong sun. A coated grade holds clarity far longer, and the difference shows on a boat kept outside.
Cleaning a marine screen is a compatibility question: salt removal with fresh water is fine, but solvent-based deck cleaners are not. The cleaning and maintenance guide lists safe agents, and the UV resistant polycarbonate guide explains the coating options.
Where a hard top or bimini panel forms part of the same job, the fabrication logic overlaps with polycarbonate canopy sheet.
Send your console drawing, curvature and boat length to oversales@rpplexiglass.com for a windshield quotation.
Frequently Asked Questions
What thickness polycarbonate for a boat windshield?
6 mm for consoles under 6 m, 8 mm to 10 mm for larger boats and offshore use. Thickness is driven by span and by spray impact, not by the screen area alone.
Can polycarbonate be cold bent for a windshield?
Shallow curves can be cold bent on a frame, but anything beyond a gentle radius needs heat forming, and the part must be annealed afterwards or it will craze at the fixings. Cold bending a 10 mm panel to a tight radius leaves permanent stress.
Why not use acrylic for a boat windshield?
Acrylic is stiffer and clearer but brittle. A knock from a fender or a boarding passenger cracks it, and a crack at sea is a spray hazard. Polycarbonate bends and absorbs, which is why most production boats specify it.