Structural integrity of large glassed areas on say, Westport 172

I wouldn't be nearly as concerned with the glass as the framed area of the hull around them.

I wouldn't own a boat with them unless they have metal covers like traditional portholes. To much to lose for to little gain.

Yachts are just one example of amazing high strength glasses. While they refer to it as Sea Glass, just look around at all the Hurricane and Impact Glass around us. We're moving into a new office building that is nearly all glass it seems. Yet it meets 150 mph hurricane requirements.

High strength glasses are actually multiple pieces of thinner high strength glass. These are then bonded together by a separate layer. Strength was traditionally achieved through the glazier process and the layers but now more chemical strengthening processes are used.

The difficulty isn't as much making the glass stronger than the hull but is doing so while not increasing weight too much as the weight of the composite material is low.

All the glasses and glass structures are further evaluated by the classification societies.

I admit when first seeing it, I still take pause. I still have to avoid of thinking of glass the way I've always been taught as fragile and breakable. But I now trust the strength as my home has huge panels of glass and I've been told they're stronger than the concrete. Same with office building and same with boats. I think it helps when you realize that it's not just one thin single glass but layers of highly strengthen glasses.

As an engineer who's company happens to install all our own glazing in my properties and graduated from UF post Andrew. I'm very familiar with glass and it's characteristics. Poly carbonate reinforced glass( impact glass) is very strong but will still break under the correct situation. Problem is once it's broken the loading on surrounding frame changes completely. Think about a simply supported beam vs a safety net like the circus performers use. The glass once cracked will try to pull out of the frame and cave in. If the wave can crack it it will certainly cave it in a few waves later.

OB as always well put and very informative.
This coming from a boater with lots -o-glass on an old Ocean Yachts .
All I know is do not push it on my double pane glass...and treat all glass with respect. Go with your gut feel on it.
It’s hard not to.

Will the real slim shady please stand up ?! Please stand up?
Lol
Interesting and fit your point.
What about bullet proof glass . Like my bank in Philly?! That looks like some good yacht glass material ?

Or glass in an armored car, but it is extremely thick.

That's funny. Name came from my teammates in basketball. They're blk and I'm white, hence the name. They were good I wasn't
I'm not familiar with bulletproof glass properties so no help.

Either one is probably not good for looking out and through..
So it defeats the purpose right?
I guess glass and seaworthiness is up to the buyer ultimately.
I cringe at the smaller yachts ( and large yachts) with the big glass picture window on the side hull of the boat just a foot or so above the waterline. not my cup of tea. Looks like possible trouble.
And ALL windows will eventually leak !
From my experience. SOBs.

Look at Skywalk at the Grand Canyon or some of the glass terraces on high-rise buildings these days. If the boat can handle the weight strength is no problem. The real problem lies in the frame and the flexing fiberglass around it We had a few members ask about replacing their leaking or stuck salon windows here lately, Imagine after the hulls around these windows have been flexing for 20 years. Not hard to imagine these hull windows leaking if not popping out completely. Not hard imagining the resale value of these boats plummeting prematurely. They look cool though, and that's all that really matters.

Lol!
Just a thought.
What you said , once it cracks it’s over so to speak .

Well anyway it’s a great topic. No matter your vessel. It’s something to really consider and respect.
I have three big 42” x 42” forward cabin windows , not sportfish fiberglassed over.
They could smash in no problem in the right situation.
But the day/night light and visuals really open up the salon on the boat wether under our way or at the dock.
Pluses and minuses, it’s up to the owner to weight them , right ?

To the OP , you got some really good information here what do you think ?sounds like it’s some strong stuff overall.
If it gives you good Visibility and looks good on the boat aesthetically speaking sounds like it’s a good thing to me.

Yes, the glass is very strong. But the problem is glass like what's installed on yacht hulls doesn't flex, it's rigid, yet the surrounding hull flexes. Same with expansion and contraction with temperature. This is why you see yacht glass has a huge amount of caulking between the glass and the fiberglass (even for glass such as salon windows), this is to allow for flex between the two materials. Does it weaken the structure of the hull, it has to due to the different properties. Glass also has much less impact resistance compared to fiberglass. Take a ball peen hammer to a fiberglass hull as hard as you can swing it and let me know what happens, do the same to the hull window.

Ask Elon Musk... https://www.bbc.com/news/technology-50547044

Glass can be very strong if loaded properly. It doesn't like concentrated shock loads, ie impacts from hard objects.

Elon gave us a good laugh. For boats, the use should dictates the design. Large glass areas should always be suspect, especially in the hull and pilothouse.

Good luck with that. I think we all know that fashion rules. People want pretty and airy. Lots of light just like in their homes. And since 90% of most recreational boat's lives will be spent on the dock seaworthiness is low on the list of priorities for most buyers.