Aluminum pilot house window install / fab question

Discussion in 'Metal Boat Building' started by astglenn, Mar 10, 2015.

  1. astglenn
    Joined: Mar 2015
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    Location: Shingle Springs CA

    astglenn Junior Member

    Greetings and thank you in advance for your assistance.

    I am building a pilot house on a 21' ex USCG aids to navigation boat. I am to the point of fabricating how I will install the glazing. I would like to consider installing 1/4" Laminated Glass into the openings for front and side windows. The largest of the windows will be 2'0" x 2'6". I purchased a sheet of 5/16" Lexan MR 10, and just cant see how it would ever stand up to wipers in a marine environment, so I ditched the idea for glass instead. I now own a really expensive 4x8 sheet of nice plastic.

    I would prefer to weld in a stub fin (Cut out panel sheet on waterjet that leaves radius opening) around the inside of the window openings with .250" aluminum and then use a rubber beaded "weatherstrip" type mounting for the glass. I have also looked at the Diamond Sea Glaze windows with their flanged perimeter frame and backing ring. Weight is a concern.

    My question is, are the "Weatherstrip" type of mountings suitable and burly enough to hold the glass in place under marine duty?

    I appreciate any insight.

    Here bis a picture of the "Weatherstrip"


    Thank you
    Glenn
     

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  2. welderbob
    Joined: Nov 2009
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    Location: Holbrook NY

    welderbob Junior Member

    Hi Glenn,

    The rubber glazing works well. On a bigger piece like that we would make a piece of molding out of starboard that srops the rubber from blowing inward if a large wave hits the from window.
    welderbob
     
  3. astglenn
    Joined: Mar 2015
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    Location: Shingle Springs CA

    astglenn Junior Member

    OK cool. I think I understand how I can fab in a Z shaped sub frame or some form of safety stop to cover that.

    Thank you for the help. This has been bugging on me and holding me up.

    Glenn
     
  4. Kevin Morin
    Joined: May 2013
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    Location: Kenai, AK

    Kevin Morin Junior Member

    Glazing Rubber Extrusions

    Glen, there are several different, but similar to the one shown, rubber extrusions to mount glazing in metal panels.

    One that I've used more than a few times had the glass mounted outside the metal and over-sized to the opening and thereby it reduces or avoids the glass being forced inside the cabin unless the sea actually caves the glass panel. (Much more force than just pushing the glass inboard.)

    I've not built for years, so I have no vendors to suggest but I think an online search for these vendor's products will show other cross sections?

    I also used the shape with a built in or fold out 'key' strip, the example you show uses the older 'separate key' strip method to expand the extrusion to hold the glazing and metal together.

    Also, always @!!! Always!! make the strip "long" and forced into the opening, in a few years there's a gap at the bottom butt joint if you don't!

    Cheers,
    Kevin Morin
    Kenai, AK
     
  5. astglenn
    Joined: Mar 2015
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    Location: Shingle Springs CA

    astglenn Junior Member

    Hi Kevin. It seems like CR Lawrance Co has most of the "Automotive type" rubber extrusions for glazing these days. I will look a bit deeper. I like your idea of the glazing being oversize to the opening. Both of the replies I have had mention some form of keeping the glass from being projected into the house on a wave strike. I agree. Good advice. I have had some green water in my face on a couple of crazy, quick turn weather events in my center console. While I never go looking for trouble, we all know how it can get. I spent a bit of time in the Gulf of Alaska in 25-30' boats. It comes out of nowhere.

    In your estimation, (Welder Bob as well) is 1/4" laminated glass enough? I can go to 5/16" or 3/8" on the front glass if I have to. I bought two Diamond Sea Glaze windows, 2' x 2' in the heavy built off shore frames for this originally. The glass is 3/8". I tabled the idea of using them due partially to weight, and honestly the front of the house ended up looking like a pair of eye glasses when I mocked them up. The 2 x 2 windows weigh close to 40 lb ea. My initial sketches did not do the ugly proper justice. The rubber mounting will allow me additional freedom to shape the glazing. So long as I keep a minimum 2.5" radius at the corners, I think I can make up for some poor design vision and planning on my part.
     
  6. Kevin Morin
    Joined: May 2013
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    Location: Kenai, AK

    Kevin Morin Junior Member

    Windscreen mounts

    Glenn, If the cabin is amidships with a bit of foredeck then usually the green ones are not on the windows? In the event that you do take one, the oversized safety glass panel is pretty stiff stuff if the mount allows it to overlap. I'd say if you needed a thicker glass in a 25'er offshore, you've got bigger problems- like being out there or having a leaned back glass surface?

    I lean them forward if possible, but the main risk in small boats is aft raked glass, regardless of thickness.

    look at these products? http://lbhproducts.com/seals_(windows,_weighbridge,_container)_and_covers.pdf
    down to page #9 or so there seems to be some overlapping types here?

    One thing that can help cabin windscreen design is to make the corners of pressed plate, so the corner piece is braked to the angle and that corner piece allow trimming the window opening close to the corner post it forms, giving less blind spot in the view. Also using a similar method in the center post- or a combination of two brakes in the center to give good column stiffness but still narrow in terms of field of view.

    Both these (assuming two piece glass windscreen) pieces become harder/stiffer/strain-hardened in 5086 or 5083 so they can provide lots of support while remaining narrow at the corners and the center post of the cabin forward windscreen. Getting bent pieces can allow narrower posts with adequate structural support.

    If you post the design others may find better solutions than you're currently planning?

    Cheers,
    Kevin Morin
    Kenai, AK
     

  7. astglenn
    Joined: Mar 2015
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    Location: Shingle Springs CA

    astglenn Junior Member

    Hello Kevin. This cabin developed as a project of left overs from our fab shop. I framed everything in 2x2, 6061. Wall thickness is .250 on the center front post and outboard vertical front posts (Front 3 posts) The balance is .125 wall. So essentially it will be post and beam with panel infills that are cut to window opening sizes. The angle of the front face is slightly rearward. I did that because the house is very much forward. There is only about 4' of boat in front of the helm. This is a Coast Guard Trailerable Aids To Navigation Boat. I was a military contractor awhile back and had access to the DOD junk pile, which is where I found this neat little boat. It has a great cockpit for fishing or diving which is my intention, but I am assuming that the ride in any sort of sea state will be fairly nasty. Its built typical military type 1A burly.

    If my slightly rear lean angle ( 15 or so degrees) of the front of the house is a big mistake, I would rather start over. I could cut the frames loose and miter the window section forward. It would take a bit of work, but it is possible without a doubt.
     
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