Big windows - dangerous in an ocean-going yacht ?

Discussion in 'Boat Design' started by Boo2, Aug 11, 2009.

  1. apex1

    apex1 Guest

    Most unlikely it will get caught on a leeshore. It is a twin engine motorboat! And the windows are several times stronger than both ABS and Lloyds require.


    To the:


    Just back from a few days sailing the Aegean sea (delivery turn for Ulas new boat).
    Staying at port is not only in winter times like now, a clever idea from time to time.
    Many many accidents occur due to schedules, where no pressure would do much better.
    As Mark pointed out: avoid weather, is the best choice of "material".

    Regards
    Richard
    thanks bntii for the drinks! But too late I have had mine on Symi Island already.
     
  2. mark775

    mark775 Guest

    Kinda cool, tho wet, and efficient in 2 meters, kinda seasick and uninhabitable on deck in 4.
    I'm going to be a little more generous - tho I would like to see something to divert a greenie on the foredeck (rambunctious throttle or coaming 4 meter in a headsea will put tremendous force on those front windows), watch your weather and I think the windows will be fine. I think the appearance is of too much glass but the aluminum structure is capable of supporting the panes. Go with Richard on this - thicker glass isn't a sight problem (Tho the weight of the glass is substantial).
     
  3. apex1

    apex1 Guest

    Its Dashews "Windhorse" nothing new with it. But Steve Dashew feared laminated glass (it can get blind at the edges).
    A proper mix of tempered glass laminated together is not too heavy, but flexes more and is much stronger than a tempered alone.
     
  4. sabahcat
    Joined: Dec 2008
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    sabahcat Senior Member

    I'll be using 10 mm shinkolite on mine
    http://www.mrc.co.jp/shinkolite/merit/index.html

    Have used it before with a very nice dark tint and saw no signs of any breakdown after 10 years in direct sun

    Good enough to use on this vessels windows
    [​IMG]
     
  5. Submarine Tom

    Submarine Tom Previous Member

    Don't confuse brains with money!

    -Tom
     
  6. mark775

    mark775 Guest

    By "blind at the edges" you mean that if they are not edge-sealed they get cloudy with time?
     
  7. Brent Swain
    Joined: Mar 2002
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    Location: British Columbia

    Brent Swain Member

    Prisms let in no more light than any other hole the same size. All they do is diffuse it which the plastic covering you see on fluorescent cieling lights will do just as well.
    Use that nice dark tint on your wheelhouse windows and you won't see a damned thing thru them at night.
    Windows big enough to crawl thru are a thiefs best friend. On sailboats I've been able to keep them too small for that. I have absolutly no worries whatever about my 6 inch by 10 inch, half inch thick plexi ports , bolted to the outside of my steel cabinsides , in any conditions.
    I've yet to see any plastic opening port which has anything but the thinnest, skimpiest plastic hinges possible .
    Troy is right , hatches give you all the ventilation you need , especially if you moor stern to the wind. I've taken several sudden knockdowns, which would have submerged any opening ports in my cabinsides, if I'd had them, and they probably would have been open at the time, as conditions were warm and light, just before the cold front or katabatics hit, without warning. That is why I prefer to have all openings as close to the centreline as possible
     
  8. troy2000
    Joined: Nov 2009
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    troy2000 Senior Member

    OK, I need a little schooling here.

    My idea of the way to mount deadlights is to have them inside--with some weather-tight, cushioning goop between them and the cabin trunk, and held in place by interior trim solidly fastened to the trunk. That way the glass (or Plexi or whatever) can be over-sized for the opening, and kept firmly in place by a strong backing that doesn't stick out like a wart on a hog, as it would on the outside.

    Do you think exterior mounting adds enough strength to justify doing it that way in spite of the aesthetics? Or does the size and styling of the boats you build simply accommodate it better, without the lights looking like they're just stuck onto the cabin?
     
  9. apex1

    apex1 Guest

    Right. The yard has to seal the edges in a "rubberized" Epoxy before installing them.


    Brent,

    this was wrong! >>>>Prisms let in no more light than any other hole the same size.<<<<
    Prisms magnify the incoming light because they can catch the light from sideways too!
    And as everybody knows, "light from above is twice the light", so, prisms can be a good solution.
     
  10. apex1

    apex1 Guest

    None of these boats has 10mm windows! That is far below class. (and sense)
    And there is no top yard in the entire world installing plastic windows on a megayacht! And tinted is good for dockside queens or accommodation windows. The wheelhouse windows (forward facing ones) should be clear.

    this picture shows ECO a 65m Blohm & Voss, guess what material was used for the windows?[​IMG]

    no, ...glass! I know the supplier since ages and have seen them building!

    Regards
    Richard
     
  11. sabahcat
    Joined: Dec 2008
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    sabahcat Senior Member

    I beg to differ

    I purchased the last of the stock used on "The Other Woman" (the one with the masts in the picture) built by AYB in 91 .
     
  12. Brent Swain
    Joined: Mar 2002
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    Brent Swain Member

    The critical angle for light hitting the surface of prism glass is exactly the same as for light hitting any other glass surface. Beyond that angle only, does it all bounce off. Makes no difference whats inside in terms of how much light gets in.Once it penetrates the surface, it has nowhere to go but in. What you are quoting is prism salemen's promotion ********.
     
  13. TeddyDiver
    Joined: Dec 2007
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    TeddyDiver Gollywobbler

    Brent.. actually there's two surfaces for light to penetrate, and bcs of the geometry, prisms let more light in thou the difference is not so significant. What's significant is where the light goes and there a prism wins without a question. Allmost same effect can be achieved with a fresnel lens (those plastic self adhesive automotive rearwindow thinghies) attached to transparent hatch..
     
  14. capt vimes
    Joined: Apr 2009
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    capt vimes Senior Member

    sydney hobbart 98

    a little offtopic but since this race have been mentioned...
    http://www.amazon.com/Fatal-Storm-Inside-Tragic-Sydney-Hobart/dp/0071361405#reader_0071361405

    this book was written by a journalist collecting the stories of several boats and summarizes the events...

    the most amazing story to me was described by the helmsman of a yacht in the 40' range...
    they had already 3 roll overs, were demasted and had a large hole ripped out of their coachroof... it even is an image attached showing the crew hunched in the saloon with the sky over the heads...
    they were running with the wind and seas making good speed with the wind on the naked hull alone... when the helmsman felt another big wave coming from astern and pushing the stern sideways...
    he crouched - tethered to the yachts with 2 lifelines - awaiting the wave to hit the boat and probably rolling it over once more...
    it did not happen and so he looked back and saw this ~40' ship surfing in the tunnel of this massive, braking wave... :eek:

    several sources had confirmed that there were up to 30 m waves recorded in the bass strait during this race... windforces of +150 km/h driving the seas against the current causing really huge - and more dangerously - braking waves...

    so - back to glass and stuff... very intersting thread...
     

  15. frank smith
    Joined: Oct 2009
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    frank smith Senior Member

    You can check it out in video on National Geographic . Very scary stuff. It does make me wonder about pilot houses on offshore sailboats .
     
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