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  #1  
Old 07-12-2010, 09:57 AM
Guest1578132542
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Largest Port holes or window size in cat hulls

Hi all.

want big windows in the hulls of my cat, but i see pain if one cops a wave slap.


before i talk to the port hole people, i'd like to have some basic understanding of portholes/window size.



the windows will be 120cm above the water.

i want them as large as possible with zero chance of breakage. (preferably 60cm high by 90 long but since all the port holes you can see on google are very much smaller, i presume this is not in reality?)


so;
how thick should the glass be? whats the max size that is reasonable?



onya,
mal
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  #2  
Old 07-12-2010, 11:02 AM
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Richard Woods Richard Woods is offline
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Judging by your freeboard (min 1.9m to gunwale) you clearly have a very large catamaran.

Both Catana and Lagoon have fitted large windows in the topsides (which I assume is where you want to fit them). There are specific standards about the strength and fastening of such windows.

A warning: It is not the waves that may cause problems, but docks, piers even other boats. I saw a Lagoon with a broken window caused by hitting the corner of a fuel dock as they left.

Not really to be recommended.

Richard Woods of Woods Designs

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  #3  
Old 07-12-2010, 03:12 PM
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thank you richard,

real world gems, which are making me ponder putting a bend in the hulls like the catanas or the easy cats.

and i'm putting the windows in the hulls themselves




those cats you mentioned look like they have normal portholes under long bits of dark acrylic.
ie very small.


i'm thinking of doing 40 cm high x 60cm long and 8 of them all round the hulls.


i can't find a single other catamaran that has windows where the portholes should be.







do you think there is a difference between yachts and cats? taking a beating when the weather gets up?


i've decided to calm down a bit after reading this thread;

Big windows - dangerous in an ocean-going yacht ?
yep, I've had ports stove in from boarding seas. I had a cabin crushed and literally shifted sideways on it's carlins from a boarding sea, ports, vents, companionway and all. I barely made it to port on that run, so yes, you can have a personal relationship with Neptune, if your ports aren't properly protected in a storm.

Big windows - dangerous in an ocean-going yacht ?
The innies sit IN the water and will have scantlings to be hammered by breaking waves.
The multihulls are Outies , hopeing to sit ON the water not be in it.




what about if i angle the top half of the hull inwards?

easy catamarans have the largest side windows i can find and the hull folds in up the top on them. everybody else seems to have miniscule portholes.








what about all those silly escape hatches those dodgy europeans install?

they seem to install them left right and center, and they are huge. and very low.




the question now is not whether big windows are dangerous in a yacht, but are large windows dangerous low down in a catamaran hull



surely it's just a matter of how thick the acrylic is and how strong the frame. yes?


onya,
m
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  #4  
Old 07-12-2010, 03:43 PM
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bearflag bearflag is offline
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There a few designs with an array of smallish square windows. So instead of having one big window, you may have 8, 9, 12, etc smaller windows in a grid.

The Monocoque/body takes most of the strain, you get some redundancy in case of breaks, windows are individually stronger, since they are smaller. You get A lot of interior light, but, not the picture frame window look.
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  #5  
Old 07-12-2010, 10:10 PM
Petros Petros is offline
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Stress on the surface of the glass (or polycarbonate) goes up with a square of the dimension, so they must get much stronger, and much heavier (and more costly) as they get bigger. The larger the "holes" in the hull structure, the weaker the structure, so it too get heavier and more costly to build.

Cleaver design might help some, position them so they are not subject to direct loading. This also goes for potential damage due to dock-side incidents (or during overland travel on smaller boats).

I too lament the tiny windows often installed on most sail boats, if I am going to be out on the water I want to enjoy the view in any weather conditions. I often wonder if it would not be possible to design large windows that are made of load capable structural material that is reasonably clear. I am not aware of any product that meets the description, likely you would have to develop some kind of filament reinforced polycarbonate. And this type of large structural window would not be able to be opened.
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  #6  
Old 07-14-2010, 01:30 PM
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rayaldridge rayaldridge is offline
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Quote:
Originally Posted by bearflag View Post
There a few designs with an array of smallish square windows. So instead of having one big window, you may have 8, 9, 12, etc smaller windows in a grid.

The Monocoque/body takes most of the strain, you get some redundancy in case of breaks, windows are individually stronger, since they are smaller. You get A lot of interior light, but, not the picture frame window look.
And also, according to the bible of good house architects, A Pattern Language, multiple lights in a window are visually much more pleasant to have than a large unbroken window.
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  #7  
Old 07-14-2010, 02:49 PM
Chris Ostlind Chris Ostlind is offline
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I tend to not see it that way.

As a career-long photographer of landscapes and architecture, I haven't had one single client, ever, ask to have their painstakingly crafted imagery divided into a multi-faceted display because it looks better like that. I tend to think like others in the craft... that wide, sweeping panoramas are the most powerful vista. There are cameras specifically designed and built to capture panorama views. Some of these cameras even capture full, 360 degree versions and they are sought after for comprehensive depictions of the world as we see it through human eyes.

There are any number of well written software programs that can stitch together images shot from non-panoramic cameras, making full 360 degree views possible. One can even shoot in the tilted up and down modes, stitching these in with the horizontal pano imagery to allow spacial viewing. More than one builder of fancy boats have utilized this technique to allow visitors to their site an opportunity to get a feel for what it would be like to come aboard.

Apologies for the visually oriented sidebar, but it serves to represent the argument.

Divided lights, as they are called, are intensely more maintenance intensive and for most sailing boats, that is one of the dividing lines between what is successful and what is not. These cruising guys are not taking their boats out on blue water slam fests with overhead breaking waves that might put out the lights. They are cruising relatively calm waters with the wife and kids and enjoying the luxury that their boats have to offer.

Looking at this issue simply as a bunch of very serious cruisers is to possibly mis-understand the realities of how most boats get used.

There will always be the Dashew's in this world and for them, by all means, get the toughest, strongest window arrangement you can design while still being able to stand watch protected and ensure that the floating integrity of the boat is maintained. Everyone else is many clicks down on the extreme oceanic scale.
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Old 07-14-2010, 08:03 PM
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rayaldridge rayaldridge is offline
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I think you're confusing photography with home-building. If you haven't read A Pattern Language, do so immediately. It will open your mind in a lot of ways, ways you probably can't imagine.

The authors take an entirely pragmatic approach to setting up their rules (or patterns.) They look at what has endured over the centuries, taking as their premise the idea that only homes that are loved will last. Out of this sea of data, they have abstracted their principles (or patterns.)

There are analogous situations in boat design. Only wooden boats that are well-loved will endure. One could probably derive a pretty good set of patterns for successful cabin layout and arrangement by looking at a bunch of hundred year old boats.
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  #9  
Old 07-15-2010, 11:44 AM
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the bible of good house architects

was probably written in the city, by people who live in a city, and probably makes sense to people who live in the city

in normalville, where i come from, these people are instantly recognised as insane




in normalville, people pay astounding extra money for view, build on ridges, hills etc, and without exception they have the largest windows they can.




if they lived in a large city, where 99% of the population have a brick wall view,
then yes, i can actually see how that inanity makes sense.

brick wall view, junkies shooting up, garbage, perverts peering in and the like. makes all kinds of sense to disguise/distort the view.




in normalville however, where the air is clean, and million dollar views abound, the largest possible windows are desired.



so i just put a kink in my hulls, like the easies/catanas/lightwaves etc and i'll put in the 40cm x 60 cm windows instead of portholes.



the FP's all have those non opening structural windows at least this size, and tiny little opening port holes beside them









Chris Ostlind,
"mis-understand the realities of how most boats get used." smack on the money there.

you just have to look at any marina to see that 99% of boats are staionary seldom used sex objects.





the old days are long gone. boats these days are like cars, and have weather print outs for 3 days in advance, and can run back to a safe port easily in that time.


the old days of having to bash into hurricanes head on for days at a time are looong gone.

thus;
i'll risk the windows, big acrylic and aluminium jobbies

comments any one?

m
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  #10  
Old 07-15-2010, 12:42 PM
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Quote:
Originally Posted by Dung Beetle View Post
the old days are long gone. boats these days are like cars, and have weather print outs for 3 days in advance, and can run back to a safe port easily in that time.

the old days of having to bash into hurricanes head on for days at a time are looong gone.

thus;
i'll risk the windows, big acrylic and aluminium jobbies

comments any one?
m
Go out to sea.........your childish dreams will soon get shattered.
Be caught by a Bora, Meltemi, Norwester or a simple thunderstorm (none of them being part of your forecast), your bigmouth will stay shut for a while.

The old days are not gone, the oceans donīt care about our attempts to brake the rules.

Being humble is one of the prerequisites to survive at sea. Proven and safe scantlings and dimensioning another.

Richard
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  #11  
Old 07-15-2010, 12:47 PM
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Richard Woods Richard Woods is offline
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My neighbour is building his own house. Because we share a magnificent view he fitted lots of windows. 42 at the last count. Then his wife came to see how he was getting on and said "where am I going to fit my eye level kitchen cabinets now?"

Personally I find that I only see waves from portlights in the hulls. Furthermore lots of windows means lots of light. If you are doing any passage making, rather than just day sailing, you'll end up trying to sleep in daylight. And then you want the hulls to be as dark as possible

Richard Woods of Woods Designs

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  #12  
Old 07-15-2010, 02:24 PM
Chris Ostlind Chris Ostlind is offline
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Quote:
Originally Posted by rayaldridge View Post

I think you're confusing photography with home-building...
Not confusing anything, Ray. We could use the typical coastal cruising design as a basis for the argument, as they are all over the place and nowhere ready for the storm scenarios so described.

Instead, let's go to Miami and look at the boats in all of the various marinas there. I'd be willing to be that at least 90% of the sailing vessels so parked have never been to the Bahamas, much less out on the open sea several hundred miles from land where weather issues become much more touchy.

Those boats do not need to have a vast collection of tiny little ports arrayed in some classic Craftsman pattern built from ballistic Lexan. Big, sweeping, uncluttered vistas are important to this genre. They stay close to shore, are not intended for anything like Blue Water expeditions and can have all the creature comforts, with virtually none of the risks associated. The nastiest conditions they will have to face are from hurricanes that hit that particular part of the coast while they are tied-up and tiny windows don't mean squat for that application, anyway.

Perhaps going back to the books and looking up the section having to with pragmatism will get things rolling? Another look at contemporary human wants and desires in habitat will also hold you well.

Just like the folks who buy Porsche Carrera RS models, almost all the owners of even fast sailing craft never intend to push their vehicles into the full capabilities of the given machine. Serious sailors already know what they need and equip their boats in such a fashion. Everybody else is playing with the imagery in their imagination.
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  #13  
Old 07-15-2010, 02:32 PM
Chris Ostlind Chris Ostlind is offline
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Quote:
Originally Posted by Richard Woods View Post

... And then you want the hulls to be as dark as possible

Behold the invention of curtains.

Way back in the 70's, I used to own a classic, '67 VW Samba Bus, complete with flip open windshield and all. Naturally, being a child of the era and fresh out of the military, I had a tendency to puff the herb every once in awhile. It was nice to be able to block out prying eyes by simply sliding my custom curtains over the windows and enjoying Hendrix, The Doors, or Zeppelin, just a bit. A sequestered sleep soon ensued and I arose feeling full of zest. ;-)
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Old 07-15-2010, 04:47 PM
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Well, as you know, I'm not usually impressed by arguments in the form of "Everyone's doing it!"

The lust for picture windows is something of a relic of the 50s, when a picture window was regarded as a status item, like fins on a Cadillac. The meme has survived due to architects who don't have to live in the houses they design-- that whole bringing the outdoors inside idea.

The authors of A Pattern Language don't say you can't have big windows or lots of windows. They say that windows broken up into lots of small lights are more pleasant to live with than vast unbroken expanses of glass, and their reasons are several. I won't go into them, since obviously the folks who are ridiculing the idea here have, like the authors of the book , devoted a lifetime to studying vernacular architecture, Know All, and have reached Different Conclusions. That's fine.

But I will say this. Aboard a boat, if you want light and space, you can go on deck. If the weather isn't conducive to going on deck, then the boat becomes a refuge against the weather, and it is very comforting to have a clear distinction between outside and inside.
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  #15  
Old 07-16-2010, 01:19 AM
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A few other questions related to portholes.
1. Is it easy to find suppliers that make custom portholes to fit on a curved (non-planar) hull surface?
2. Is it legal, or Coast Guard approved, to have tinted windows or reflective (low-E) film on the pilot house in front of the helm station?
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