Perspex windows and going blue water

[Independence]

I've recently purchased a She 31b and am fitting her out in preparation for blue water passage making.

It was my intention to change the perspex windows which are a selection of 4mm and 3mm perspex to toughened glass which is something I did on my last boat.

The difference with this boat is that there is a slght curve on the coach roof and I don't want to have the problem I had before of forcing the coachroof (unsuccessfully) in a straight line as they are fitted. On top of that the window frames are flat stainless steel that bolt through the frame and perspex.

Unless you can suggest otherwise it looks as though I'll be forced down the perspex route. Does anyone know of a toughened perspex I should ask for? Is 4mm considered strong enough? The boat has already been trans-atlantic with these windows but they seem bit of an un-necessary weak point to me.

Any comments welcome.

 

[sailorman]

polycarbonate ( Lexan or similar )
talk to Ipswich Plastics

 

[Avocet]

At work we use something called "Resist 65". It's an "impact modified" acrylic and I've been very impressed with it's toughness. It has all the good properties of Perspex (good abrasion resistance and optical properties) but it's as tough as some polycarbonates. We make protective screens for taxis out of it and I've seen it take a real beating without shattering.

Whether or not 4mm would be OK for blue water, I don't know. I guess it depends how big the panes are.

 

[highandry]

Agree with sailorman, Lexan or one of it's family. a .38 round nose lead bullet at 900 fps wouldn't penetrate it at 30 paces (under test) so it's tough stuff. Used in riot shields in the past.

 

[Independence]

It certainly seems to be the stuff I need. I'm sure a supplier will make the right recommendation in terms of thickness but any thoughts would be welcome.

 

[Tranona]

4mm polycarbonate will be plenty strong enough. Any thicker and you will have difficulty in getting the material to follow the curve. Use the old ones as templates and drill clearance holes for the through bolts to avoid setting up stress points.

 

[sailorman]

talk to Ipswich Plastics
6>8 m/m more than strong enough, i would think depending on window area involved thicker to stop flexing.
i think lewmar hatches are only perspex

 

[Athene V30]

Just replaced Flipper's windows with 6mm perspex. Slight bend from fwd to aft.

Hope it is strong enough as planning to do Jester Azores in 2012!

 

[Noddy]

I too may change to perspex windows at some point.

Is there an issue with abrasion? I've seen some windows that are almost opaque with tiny scratches.

P