Offshore Marine Glass

Hello,

I'm ready to install window glass in a new deck hatch/skylight I've made. I really have no experience with marine glass and was hoping someone here did and would offer some advise.

After reading what I could find on the net, here's what I'm currently leaning towards. My opening size is 20" by 18" and I need a total of six pieces of glass. I'm considering a 3/8-inch thick tempered glass and using a sealant like GE's Silpruf SCS2000 or Dow Silicone Building Sealant.

The local glass company says I don't need tempered glass over 1/4-inch thick, however, I see that Freeman Marine http://www.freemanmarine.com/Windows_Heavy_Duty.htm uses 1/2-inch glass.

I'm not going to use 1/4-inch, but should I consider 1/2-inch? And I really don't want to use plexiglass because of the way it yellows over time. Are there any other options I should consider?



Thanks
Brian
www.mv-jezebelle.blogspot.com

 

3/8" sounds reasonable. It is common for something to fall on the glass, from a tool to some part of the rigging. A bit of extra thickness will give you a lot of safety without adding a lot of weight.

 

I've been long preferring laminated glass over tempered in skylights, ports and large pilothouse glazing. Especially for overhead and windscreen glass, laminated is just the safer way to go. It's not as strong as tempered of the same thickness, but scantlings can handle this and they do make tempered laminated glass too. In a butterfly like that, Lexan or laminated would be the only logical choices.

 

Plastic is lighter and your hatch hinges will be happy with a light window.

Also remember that during the skylights lifetime it will be refinished many times. Those protective grates are a nightmare to refinish and make it hard to clean the windows . Plastic needs no protection.

DONT USE SILICONE !!!!!!!!!!!!!!!!!!!!!!


I repeat DONT USE SILICONE or you will regret it every time you refinish.

Seat the windows flush so no water can stand on the window.

 

Plastic tends to do several things, none of which is desirable, particularly in a butterfly, where access is limited at best. Agreed plastic is lighter, but you have to live with all the other stuff, which I find unacceptable.

Protective grates can be removed for refinishing and most, if well designed, screwed on from below, making this fairly simple. I also agree about silicone, but with glass and plastic light installs, it's the best product going, unfortunately. Michael is correct, it will cause you untold headaches, if sloppily employed, so carefully tape off the rabbit and the glass, apply the goo, set the light, then carefully peel the tape off. If done with care, it can be neat and clean, without the common issues. If done sloppy, you'll regret it's use.

Most butterflies have a limber at each lower corner and shed water nicely (again if well designed). If not, as Michael suggests, make provisions for water to shed. The obvious choice is a limber in the corner of each pane frame.

 

I was thinking of building my own flat skylight out of 2 layers of windshield glass with a bronze colored filiment between. Supported panals 8" x 16" put together. What would be the best adhesive to use to laminate the glass? Thanks.

 

The only issue I have with plastic is checking after years in the sun. Plastic is so simple to work with that its easy to replace the checked windows when you refinish.

When sunlight passes thru a glass or plastic window the paint on the inside of the frame gets burnt. You should defend against this this by blacking out the perimeter of the window. This black shade band protects the bedding compound and the interior window frame paint from the sun.



sorry about the poor detail photo.. examine your automobile.

http://

 

Thanks for the replies, a lot of good suggestions here to consider. I actually built the protective grates to hinge so I could keep the windows clean.

I like the sound of tempered laminated glass. Do you think this is something a local glass company could order, or is there somewhere else I should order it from?

Standing water at the bottom of the window was a concern. I was considering a beveled glazing edge around the window. I'm not familiar with the term limber, however, I think you're referring to cutting two beveled notches in the wood, one on each side of the glass to shed water. I really like that idea.

Thanks guys, I really appreciate the replies, this is very helpful.

Brian
www.mv-jezebelle.blogspot.com

 

Laminated glass is never tempered as far as I know. Laminated windshield glass is available from any local glass company that does windshield repairs because it is standard for many trucks that still use flat glass. That is what I use and recommend for builders of my boats.

 

Great discussion! I’m glad I asked the question before purchasing tempered glass for my project.

After receiving the suggestions to consider using laminated glass, I made some calls to a few different glass shops then watch a YouTube video http://www.youtube.com/watch?v=_7W2kRtV5tA that showed laminated glass being hit with a hammer. That video sold me on the laminated glass. If something was to makes it past my protective grate and hits the glass hard enough to break it, with tempered glass I’ll have a gaping hole. And with laminated glass, I’ll still have some protection from the elements. They do make a laminated tempered glass, but at over twice the price, I’m not convicted I need it. I'll be placing an order for 3/8-inch laminated glass later this week.

Brian

 

Tom, tempered laminated glass is available, but not cheap, nor commonly available (you have to order it). It's stronger and tougher than regular tempered.

Stan, don't make a glass sandwich with some "bronze colored filiment" in between. There are three common colors to laminated glass, clear, green and blue. The picture above shows green and this is what is usually employed in a car too.

You can get a ballistic film from 3M that will greatly increase its toughness. I have it on every window in my house. This film is available in several colors (including bronze), can knock down 99% of UV A and B and will withstand a 150 MPH shot from an 8 foot 2x4 fired, from a cannon (that's how they test it). Yep, the glass breaks, but the 2x4 doesn't penetrate the broken bits, held by the film.

I made the mistake of telling the other half about this stuff, several years ago and she was so impressed, she made me have it installed on all 27 frigging windows (and door glass too) in the house, in spite of the $3,500 bucks it cost. Never, I mean never show the other half stuff like this.

 

You would also have a gazillion bits of glass in the bilge for the future owners to contend with since you will never find it all. Once saw a 5' X 10' sheet of tempered explode. Nothing left bigger than 1/2". Probably dependson the tempering process. When driving with polarized eyeglasses on, look at other cars rear windows. Tempered glass will show a varigated color pattern.

I have that film on the big windows. Still add the plywood for hurricanes though. Ditto the high cost too. Liz's couches being recovered from UV exposure before the film was added was not cheap either.

 

Project up date

Well I didn't use 3/8-inch laminated glass after all, we went with 1/4-inch instead. I don't know if it was just are local glass vendors are not, but there was a $600 price difference in the two sizes.

Wave impact and storms have been our concern all along and why 3/8-inch glass was the first choose. I think we’ll just use plywood as mentioned by Tom for added protection during bad weather. Since we're planning to keep a cover over the skylight when not in use to help protect it from the elements, I'll just slip the plywood under the grate and over the glass, the plywood won't be seen anyway with the cover on. Maybe instead of using plywood, we could use Plexiglas for the added protection with the cover off.

The hatch is finished now except for latches and attaching some type of window crank/opener. And BTW… the lids are very heavy with 1/4-inch glass, the 3/8-inch may have been too much anyway.

Best

Brian



Anyone that’s interested there’s other photos at
www.mv-jezebelle.blogspot.com

 

Remember in all this its the risk of losing the boat in a storm and shipping tones of water through broken glass or using thicker and sleeping peacefully and riding out a storm .
The sea is unforgiving and its your life and the lives of others plus the safety of the boat you playing with !!

 

Storm shutters will make that wonderfully done butterfly, sufficiently stout. Good work Brian and yes, they're always heavy, if built right.