What Glass for "Glass Bottom"

Outboard designs up to 14'

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sterbejj
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What Glass for "Glass Bottom"

Postby sterbejj » Sun Aug 20, 2017 8:37 pm

I am interested in building a rowing skiff for my son that features a viewing window in the bottom of the boat, something like the "Glass Bottom" design. What glass/plastic is recommended/specified for the viewing window in that boat? I chatted with a local glass supplier about this - they recommended bulletproof Lexan, 1-1/4" (30mm) thick. That seems excessive. I considered automotive window glass but that is typically tempered glass that will shatter into a gazillion pieces if it breaks which would leave a monfucious hole in the boat. What glass was used in the boat as shown on the http://www.boatdesigns.com/9-6-Glass-Bo ... ducts/905/ page?

rleete
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Re: What Glass for "Glass Bottom"

Postby rleete » Mon Aug 21, 2017 6:36 am

I would use lexan, but 1.25" seems quite excessive. Depends on the size of the window, I suppose. For a small one as shown, 1/2" is probably sufficient. If you want it bigger, go thicker.

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Bill Edmundson
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Re: What Glass for "Glass Bottom"

Postby Bill Edmundson » Mon Aug 21, 2017 8:27 am

I would think automotive laminated safety glass is the choice. Tempered will shatter and leave a big hole in the bottom of the boat. Laminated might crack. But, it won't leak(as bad).

Bill
Mini -Tug, KH Tahoe 19 & Bartender 24 - There can be no miracle recoveries without first screwing up.
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JimmY
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Re: What Glass for "Glass Bottom"

Postby JimmY » Mon Aug 21, 2017 9:17 am

I have a friend who is a research scientist at U of M, and he told me a story about a new pressure vessel they had built. They used 6 layers of laminated glass for a small window into the vessel. The first time they tested it under pressure they heard " crack, pssssss, crack, pssssss, crack, pssss, crack, psssss, crack, pssss, blam (glass flying through the lab)!

You want one layer of thick glass/plastic.
-Jim
Nothing says poor craftsmanship like wrinkles in your duct tape!

rleete
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Location: Rochester, NY

Re: What Glass for "Glass Bottom"

Postby rleete » Mon Aug 21, 2017 10:06 am

This site: http://www.hydrosight.com/acrylic-vs-po ... omparison/ may be of some help.

After review, you probably want acrylic. Although harder to work with (it can chip), it's much more resistant to UV, and it the typical choice for aircraft windows. Not as impact resistant, but unless you plan on beaching your boat on the rocks, should hold up better. It's more resistant to surface scratching, so should retain optical clarity longer.

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sterbejj
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Location: Eldersburg, MD

Re: What Glass for "Glass Bottom"

Postby sterbejj » Mon Aug 21, 2017 6:35 pm

Much thanx to the folks who have replied to my query thus far. I'm still mulling my choice using the information provided by folks who replied. One thing I would like to know, exactly what material was used for the window in the boat shown on the boatdesigns.com web page for the "Glass Bottom" design?
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