MV Catapult Windows

Any see-through bits
mySerenity
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Re: MV Catapult Windows

Post by mySerenity » Fri Jan 18, 2013 9:28 am

it was when I launched, I was all set to get one when I found sailboats don't require them
The same when we launched.
James
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rexd666
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Re: MV Catapult Windows

Post by rexd666 » Fri Jan 18, 2013 1:09 pm

I am pretty sure that the heat impacts for plastics would work the same as glass. So first physically shading the surface is the best option. After that you need to reduce the solar energy being transferred through the window. This generally is reduced through toned glass, where you balance the amount of visible light that passes through the glass versus the light waves that transfer the heat. So some dark grey products have very low SHGC, but they let through a lot less light.

So for a plastic a tinting film should do the same work, and I am pretty sure 44C has posted else where that it was very effective for him.

If you look through the window from control position I don't think you could tint it when complying with the standards,same as a car windscreen.

Have a look on online for glass performance data as it is published and Visible Light Transmission and SHGC are the two main things you will need to look at. I checked 3M tint and they also publish the same technical data so you can evaluate the options.

Full disclosure I work in IT for a glass company.

Steve

groper
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Re: MV Catapult Windows

Post by groper » Sat Jan 19, 2013 10:32 pm

In the standard i posted earlier, 70% transmisssion is required and thus grey tints are typically allowed in the front windsheild.

I have redesigned the entire cabin, but to make the new design work i will need curved and toughened glass - which sounds expensive... do you know what sort of price i will be looking at if i used curved and toughened glass panels in 8mm thickness? The panels will be roughly 1000x1000 with a 2000mm radius bend... it seems there is only a few places in australia that can do it, this is one of them;

http://www.bentglass.com.au/

I will post a rendering of the new cabin tomorrow and see if you guys like it or if i should go back to the drawing board :mrgreen:

rexd666
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Re: MV Catapult Windows

Post by rexd666 » Sun Jan 20, 2013 5:42 am

8mm Grey would be about 35% visible light transmission thicker glass in tones means less light, not sure if it is available in 8mm 4,5,6 and 10 I know are.
Custom curved will be expensive, I think they have to build forms to bend it into. Never priced it but in the past anyone I asked about has just whistled and said lots of money. Certainly to do windscreens they had forms and were bent in large oven production line, but that was repeatable process.

If you want curved I would say plastic is cheaper, or simulate curve with flat sheets. But ring and ask those guys for a guide price.

groper
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Re: MV Catapult Windows

Post by groper » Sun Jan 20, 2013 10:33 am

Yeah i figured the price would be sky high... but ill give em a ring none the less and find out - on their website they say its "more affordable than you think", but we shall see...

So heres a rendering of the new cabin idea... all bent flat panels, no compound curvature, what do you think? I could get rid of the bent glass front facing windows if i leave the curvature in the A pillars, but recess a flat pane of glass, still raked aft, inside the pillars.

Image

Image

Image

groper
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Re: MV Catapult Windows

Post by groper » Sun Jan 20, 2013 7:48 pm

Ok, ive decided to go for the flat windscreen but maintain the curved A pillars. It looks kinda trick and avoids the extra cost of bent glass.

Ive also thought about the sun shade / eyebrow and that it could be vented like a spoiler to let the air pass through it like a wing slot. Above this, ill cut in 2 hatches with an extra lip to catch the airflow thats forced under the eyebrow in an attempt to improve ventilation. Something like this;

Image

Ive also seen an interesting method for creating the window bonding flanges... its so simple i dont why i didnt think of it sooner... The cored panel is infused with the window cut outs chamfered off at 45deg and the 2 skins are brought together to form a single skin solid laminate where the window edges fall. After the infusion, the solid laminate is trimmed back to a 50mm flange and the windows are simply bonded onto this flange to finish more or less flush by the time you allow for the flexible adhesive and the thickness of the window plastic. Heres a pic borrowed from Rob Denny`s harry proa build which shows the result;

Image

And a close up;

Image

mahnamahna
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Re: MV Catapult Windows

Post by mahnamahna » Sun Jan 20, 2013 8:44 pm

Hi Groper. I too have a 50mm flange for attaching my windows into the boat. I decored the outside skin and core (balsa duflex) by 50mm on the outside of the panel. I then rounded the edge of the outside glass and core to make a nice rounded radius for the glass frame to go over as it transitions from the inside skin to the outside of the boat. I then glassed approx 120mm glass tapes from the inside of the inside skin, over a cove against the balsa and over the rounded radius onto the outside skin about 50mm. I laid down 8 layers of 450gsm tape to make a 6mm thick frame all the way around each window, staggering the point where the single length tape joined itself at each end. I laid peel ply on the final layer. It set super strong with little more work required other than trimming the edges. If you want to see pics go here http://yikes.com.au/2012/06/06/window-dressing/ and follow on into the next month.

My quote for poly over acrylic was only 20% more for poly, I am going with clear with a silver tint.

Cheers, Paul

groper
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Re: MV Catapult Windows

Post by groper » Sun Jan 20, 2013 9:29 pm

Wow paul, those window frames must be bloody solid! did schionning specify this layup schedule around the windows or did you get it from somewhere else??? I was going to use much less glass than this and build up a solid laminate around 2.5mm thickness - so about half of what youve done... i guess it depends mostly on how schionning determines the cabin loads - which form an intergral part of the cross beam structure no doubt in his designs...

A new problem ive though out using this method is that i will have to build a curved mold and i wonit be able to bend flat panels with this much curvature and a solid glass edge for the windows.. damn it, just when you thought you had it all figured out :mrgreen:

mahnamahna
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Re: MV Catapult Windows

Post by mahnamahna » Sun Jan 20, 2013 9:38 pm

groper wrote:Wow paul, those window frames must be bloody solid! did schionning specify this layup schedule around the windows or did you get it from somewhere else??? :
I got the spec from the boatbuilders that share my shed. They worked at Boatspeed (they built Ellan Mc's boat as well as the Oman tri's etc) and this is the spec they used for building window frames (their specs call for 5mm solid glass frames, I settled on 6 layers of 120mm wide glaas tapes (450gsm) that span the entire frame, and 2 layers of 50mm tape that fill out the flange only, to about 6mm of solid glass). I found the method super easy to do, and yes, it is incredibly strong. I reckon aliens will find the window frames 1000 years from now and wonder what kind of craft they came out of, the rest of the boat long since having turned to dust!!!

No doubt I have over built them, but I have put a lot more window into my boat than the usual Schionning, for example I have wrap around windows into the bedrooms that no other boat would have. I beefed up the mullions too, just to be safe given my windows wrap around all the way around my turret because of the lack of mast in the middle, so over built was just to be on the safe side.

groper
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Re: MV Catapult Windows

Post by groper » Fri Aug 30, 2013 3:29 pm

Ok, need to cut out a bunch of windows... how are you guys reinforcing /edge closing the window cutouts of cored panels? - ive seen your method mahnamahna, just looking for other potential methods...

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