If the SEAVIEW were for real... - those picture windows...

[kowalski]

Back in the day when the show was on, it was inconceivable that a real life sub could actually have picture windows like the Seaview.
Nowadays, would that be possible with some sort of polycarbonate? How thick would it have to be to withstand all that pressure at 5000ft depth?
I got the following information]Pressure of 5000ft water column is ~2200 psi.

Lessee, clear PVC has a compression strength of about 8000 psi,
Polycarbonate is about 9500, Tempered glass runs about 20,000 psi. Quartz gives very high values (160,000) if pure compression but much lower values in tension or if there are imperfections, which means that we'll not use it here even though in real world applications with very carefull design it may be an ideal material.

Stress in a flat plate supported arount the edges and subjected to a pressure load is beta*q*b^2/t^2 (thanks Roark's) where beta = .2874 for a square plate, q is the pressure, b is the length of a side in inches.
Thus, if we want to limit stress to 20,000 psi, let's say that the windows are 36" square. This get's us a critical thickness of 6.4 inches. If we limit that to Polycarbonate's 9500psi, then we're looking at 9.3 inches.

Polycarbonate has a density of 1.2 so this window will weigh in at a hefty 522 lbs each. Chugging the numbers, I get a thickness of about 16" for 20,000 psi
strength material, and 24" thick for Polycarbonate's 9500 psi strength.

As to how to make it not leak, that's a whole nother issue: we're already ignoring little things like 'is this plate carrying any of the ship hulls stresses' and so on. Suffice it to say that it's possible, but barely and hugely expensive and impractical. [/quote]
http://www.iann.net/vaults/voy age/target19.html
In that photo looking forward you see two of the windows. As you can see there were added supporting beams. Also, there were "collision screens". These were solid steel shutters that would close at depths beyond "crush depth" (whatever that is) and provide extra structural support.
http://www.vttbots.com/Graphic s/interiors_nose.jpg
Here is a model of the observation room:
http://www.culttvman.com/asset s/images-SFTV-2005/davidmer57s ea603t.jpg
It shows the layout of the support beams around the area.
Would it still be in danger of leaking with all that support?



[quote]Sure]

How could such windows be watertight?

K.

[desert boat]

I think this was all

I think this was all part of a 'cross-over' story that was never shown because at the time it would have released highly technical planning on the part of Gene Roddenberry's secret writing staff. If you remember, in Star Trek IV, Commander Scott (Scottie), may his soul rest in peace, traded the formula (on a trip to 20th Century Earth) for transparent alluminium (is that spelled right?) for some panels of the same to construct an aquarium to transport a pair of whales back to save 23rd Century Earth. Somewhere during an earlier time trip, Admiral Nelson got his hands on the formula and the Seaviews' windows were created.

[tom dougherty]

The windows are constructed with

The windows are constructed with unobtainium. Seriously, in his book "The Silent War", John Craven does discuss some work done with a type of glass for submarine hulls, as glass actually gets stronger with compression. It was never followed up, and the objective was around hull strength and not transparency.

Not to ruin the fun, but in most waters outside of tropical areas, the best one could hope to see is maybe 10-50 feet, due to the turbid material in the water. Even in clear waters, divers and SEALs operating near submarines never see the full length of the hull, maybe at best a 100 feet or so. In the Atlantic area around Groton, they probably couldn't see the submarine if they were only 10 feet away! So, the windows on the Seaview wouldn't really offer much of a view on the ocean.

[kowalski]

They'd have their use, but

They'd have their use, but then again you don't use a 460ft sub to go sightseeing. I supposed in these cases you use the Diving Bell or the Flying Sub, leaving the windows just to spot giant squids etc..

By the way, I wonder if a hangar for something like the Flying Sub or Diving Bell would cause stability problems in a real sub. Then again, from what I could tell the Flying Sub hangar was permanently flooded and the Apple-1 (bell) went through some sort of airlock.

The Seaview also had some strange compartment starting in season 3 named the "pressure hatch". It was a hole in the ground where divers could go through. That nutty Irwin Allen was probably inspired by the diving barrel in the Disney Nautilus.