Reinforcing Windows

[gramos]

what do you think of this?...
I want to put extra polycarb windows over my original fwd windows to give greater strength to them on a pending transat voyage .
My plan is to overlap the existing fwd p/c ,s and bolt through the surrounding coachroof , adding more "crash resistance " to waves over the bows .

the existing ones have slight crazing but are 10mm thick , so another 10mm , bolted over the top should enhance the overall structural integrity ?

[sarafina]

I would think that the structural issue is the bolt thru more than the material thickness... I would look at creating an installation where the interior and exterior material supporting the windows at the bolt thru locations was reinforced, rather than just adding more window material... Perhaps, depending on the look of your boat, wood surrounds on the interior and exterior to support the fiberglass?

I might be wrong, and have never lost a window myself, but the impression I get is that in emergencies the windows fail more often at the bolt thru than the actual material failing...

Anyone confirm or deny this impression?

[smurphny]

Have often thought about the fixed window issue. My side cabin windows are larger than I'd like. Replaced them last year (w/ 3/8" u.v. plexi) because they were crazed and obviously brittle from 40 years in the sun. I considered some horizontal cross bars on the inside to stop any deflection before the plexi would break but haven't done it yet. I did make some 1/2" plywood emergency panels cut and fit 2" larger than the openings and ready to put into place with through 5/16" carriage bolts/wing nuts and 1X3 cleats behind that would swing out and pull the ply in tight pretty quickly. They stack up into a neat bundle that stows easily.

[tager]

That's what I was thinking, storm shutters.

[minaret]

I plan on cutting my new storm shutters from fiberglass flat stock with appropriate lightening holes to keep down weight/maintain some visibility. Thickness will be about 1/4", looking at mounting them so they can slide into a track around the windows instead of bolting. I have some big pilothouse windows...
Some of the guys in the yard still say I should go with aluminum panels to avoid "potato-chipping", but I'm thinking if I bag the flat stock on our table and let it cure for a few days before pulling it it'll be fine and then I can put a nice finish on them.

[perchance]

I would think that putting a window over a window may affect visibility if any thing gets between the two panes. I like the storm shutter idea. You could have a narrow slot to give partial visibility and still maintain structural integrity.

[Hudson Force]

[QUOTE=minaret;687888].............. Thickness will be about 1/4", looking at mounting them so they can slide into a track "

I favor the idea of a heavy weather protection over a portlight sliding into a track and being a slightly larger plate than the portlight and therefore pressed against the opening with any wave forces. I'm also surprising myself thinking that I have a comittment to boating jargon. I can't call a fender a "bumper"; I can't call a line a "rope" and I can't recognize anything on a boat as a "window"!

[gramos]

Ok its perhaps wrong terminology but looks like it was understood , the sizes are 1 metre x 600mm so they are quite large areas of polycarb and they are screwed into the coachouse roof on a bed of sikaflex . IMHO ,not a particularly strong fixing method for such a large pane .

perchance , a good point about the gap in between getting misty , had not thought of that , I can remember some secondary glazing panels in houses in uk where moisture stains inside the 2 panels caused clouding , and once sealed cant be cleaned .

maybe storm boards of ali/plexi/or just straight grp would be better and just place them in when needed ?

[captain58sailin]

We used lexan panels and bolt them over the existing windows on each corner. I am looking to convert to something strong enough to eliminate the need for the storm window scenario.

[Southern Star]

Gramos, for all the reasons cited storm shields are typically installed, as you say, only when needed. Aluminum plate is relatively light, easy to cut and, as the panels are fairly thin, also relatively easy to store. You could us wood with routed slots, or aluminum c-channel elevated by wood or plastic, in order to clear the existing fixed portlights.

Brad