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S&S Swan Maintenance - Acrylic strength in foredeck hatch
21 July 2016 - 21:42
Join Date: 05 August 2010
Posts: 162

Acrylic strength in foredeck hatch

Dear all, especially Lars,

this is probably a question best discussed in the forum.

I am in the process of replacing the foredeck hatch on 48/039. The cutout on the Swan 48, including an inner wooden cover, is 620 by 800 mm. I have an offer for an acrylic pane in a stainless steel frame, and the strength of the acrylic would be 12 mm. The whole product is CE-certified as category A (high seas), but unfortunately that does not necessarily imply that it really is appropriate.

Some companionway hatches are about the same dimensions and can be stepped upon, but I still wonder about what is a sufficient strength for the hatch. In other words, is 12 mm sufficient? The manufacturer claims that the pane can easily be stepped upon as it carries in excess of 500 kg, and that they have even tested it by driving a car across. Again, that is not necessarily conclusive; if the acrylic is lying flat on an even surface, it can probably even take a truck. Anyway, I am not worried about cars driving across the foredeck. I wonder about the force of a breaking wave, though.

Any thoughts about sufficient strength for a foredeck hatch of this size?

Fair winds,

Martin (48/039)


22 July 2016 - 11:08
Join Date: 02 January 2008
Posts: 1547

Dear Martin

The big hatches on the market generally use 15 or 16 mm thickness for this size of opening. 12 mm just meets the requirements in the hatch standard ISO 12216, depending on the support arrangements along the edges, and if there is curvature in the panel or not.
Kind regards


22 July 2016 - 21:48
Join Date: 05 August 2010
Posts: 162

Dear Lars,

thank you very much for the information! I did not know about the minimum requirements, I just felt that 12mm is not very strong for the size -- so thank you for supporting that hunch. By the way, the offer in question regarded an even hatch without curvature.

Best regards,


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