Big windows - dangerous in an ocean-going yacht ?

That was some mean stuff to stove those seemingly proper, small windows. I wonder if they popped in from improper installation.

 

If I remember correctly they were 30-35' seas and the yacht got caught beam to with engine problems or the like..
Though I have never experience it, I keep hearing that the drop onto the side from height is the load which causes these failures in yachts, not the wave strike proper as is the case in ships.
Trashman's windows failed when she fell off a wave into the troth.
Also the case of Winston Churchill sinking. Though I think the hull planking was stove in when the yacht hit the water for her.

The descriptions are of the yacht "falling" off the wave..

 

Frame loading and, therefore size, becomes the critical issue here.

Super glass is great but if the frames wont hold the load then there's

no point.

I'm in the "avoid the weather" camp on this one.

I like the saying, "You'll find lots of agnostics at sea but you wont find too

many (if any) in a bad storm!"

-Tom

 

On a sailing yacht absolutly deadly. Should not be considered.
I know, every super yacht as some. And they brag about the strengh.
B.S. A very bad weather can take any window, anytime. For serious navigation, deadlight should be mounted, not a windshield large like a tennis court, as it seams the trend.
Cheers
Daniel

 

When I bolt the half inch plexi over a hole in the steel cabinside, with a 1 1/2 inch overlap, there is no way the steel frame is going to break first. A wave that will punch a hole in a supertanker will simply cause a small boat to bounce away. Without the huge mass of a supertanker trying resist the wave , there is no way the loads will ever come anywhere near the loads on a supertanker.
When I was working on an expensive 60 footer, I warned the owner about the flimsiness of the lexan opening ports. He said "But it's Lexan". I pointed out the tiny bits of plastic and the tiny hinge pins holding them together . Later ,a sistership had all her ports on one side blown in in the Molokai channel.

 

Ok, so how do one decide the size of the windows. One's gotta have them.

 

Ponder over this in case you are not sure of the strength of the sea. My cousin is a captain and was called up one bad night to slow the ship down.

Next day a bow inspection revealed 1inch steel rolled like butter.

Ive never forgotten that when pondering strength issues.

I would ask myself --"do I need windows"

 

And the Lexan can't take UV. It's an interior bullet proof, not for exterior.
Makrolon is for exterior.
Cheers
Daniel

 

Aye Frosty, Does your cousin know you have a cousin

Grab a 20mm piece of iron and file the hole a few mm larger. Then go see how effortless a laser cutter cuts it out. Pisses me off completely. And those bending brakes... it's like they bend paper.



Unfortunaytely one has to let go of the manly ego sometime. One can probably (me anyway ) see through the cabin or the hulls, but windows makes it so much less effort

I think one can also assume there would be places you do not want windows

Again, how do one decide what size the windows should be. Large windows are nice for all round views and letting some natural light in, but it would be less nice to get one knocked out and your berth gets flooded.

Ok guys, the hull is flooded. We are going to take a bath each before we pump the water out. Who goes first. Last one washes the bath...

 

I don't believe this is any mystery for NA's?

Should not be too tough to engineer panes and attachments which approximate the strength of the panel they are bonded to.
Or to put it another way- should not be too tough to determine just how large they can be and still approximate panel strength.
Whether applied in practice on production vessels... not likely as none of the rest of the boat is designed for the loads seen in the worse case.

For my refit I just bought ports of reasonable size and robust construction & carry storm shutters and a decent bottle of good rum.

A bit of information about forces provided by Don Jordan in a discussion about his drogue and where he believes the highest loads are seen:

"We now have enough information that we can apply the same analyses to the Winston Churchill.
We can estimate the speed of a breaking wave (but not a non-breaking wave) if we know the height of the wave. The breaking wave that destroyed the Churchill was estimated by several observers to have a height of at least 45 ft. Such a wave would be moving at about 30 mph. Therefore, when the boat had been picked up by the wave it would be moving at that speed..
As the Churchill slid down the face of the wave on its side, there would be very little friction or drag, because the water supporting the boat would be moving at the same speed and would accelerate with the boat. With no friction the boat could reach a speed of 67 mph by the time it reached the trough. If we assume only half of this speed increase, the boat would strike the green water in the trough at over 50 mph.
This velocity is equivalent to a free fall from over 70 ft. This clearly explains the sequence of events which destroyed the Churchill. A boat striking green water at this speed can incur a force of over 200,000 lbs."

 

in the last days of ww2 the germans launched midget subs to combat the allies and it was found that during depth charge attacks they just got pushed aside with little damage

 

i would prefer round ports and shutters just big enough to let light in

deck prisms, is there a reason they cant be hull mounted?

want to look around go topside

 

Hi Wardd, I've been searching for prisms for that exact reason. Be great if one can find something like that. I also asked one of my friends who studied light and related stuff but he didn't look impressed with my request.

 

lots of prisms on google

 

Ah, but you want something that can accumilate the light in a bundle, transfer through the hull in a beam and scatter on the inside.

At night you can introduce a single high power led to make light...