"New" HMS Prince of Wales sinking analyzes

[lwd]

... Maybe my memory serves me wrong, but IIRC the blast wave has a slower speed and consequently travels less distance if the detonation occurs under water as opposed to an explosion in the air. It's logical, since the explosion travels in a far denser medium, which offers much more resistance.....

I'm not sure what exactly you mean by "blast wave" but the speed of sound and the speed of shock waves tend to be greater and retain their force further from the source in dense media.

[Bgile]

and upward venting is far preferable to inward venting

I think this is an unwarranted assumption. Inward venting can be absorbed by the design of the protective system. Upward venting can cause flooding over the top of the system.

[alecsandros]

Point noted, but at least in this case Duke of York was able to complete its task as required and didn't have the worst hit ratio.

Yes, the Duke put up a good battle...
I believe HMS Anson incorporated most of the knowledge acquired during KGV classes battles. I'll re-read Allied BBs to see what technology was built in it

[alecsandros]

I'm not sure what exactly you mean by "blast wave" but the speed of sound and the speed of shock waves tend to be greater and retain their force further from the source in dense media.

Yes, sound does travel faster in water. I don't think it's the same with explosions, and I think I remember the Germans pre-war experiments about this...

[Bgile]

I'm not sure what exactly you mean by "blast wave" but the speed of sound and the speed of shock waves tend to be greater and retain their force further from the source in dense media.

Yes, sound does travel faster in water. I don't think it's the same with explosions, and I think I remember the Germans pre-war experiments about this...

I agree with lwd, and I think it is the same with explosions, although they still have to obey the inverse square rule.

[dunmunro]

and upward venting is far preferable to inward venting

I think this is an unwarranted assumption. Inward venting can be absorbed by the design of the protective system. Upward venting can cause flooding over the top of the system.

The point of the SPS/TDS is to protect the citadel, and by definition this is the area inside the final TDS/SPS holding bulkhead. Inward venting must stop at the final bulkhead if the citadel is to be protected, so if there is excess pressure it must go upward or inward and upward venting is preferable to destroying the final, holding bulkhead. We should remember that on the NC, the torpedo hit vented over the TDS and flooded areas inside the citadel, so it vented inward and upward of the TDS.

[lwd]

I'm not sure what exactly you mean by "blast wave" but the speed of sound and the speed of shock waves tend to be greater and retain their force further from the source in dense media.

Yes, sound does travel faster in water. I don't think it's the same with explosions, and I think I remember the Germans pre-war experiments about this...

Well here's a little experiment you can perform. Take an M-80 (a large water proof fire cracker used for agricultural purposes - scaring crows - here in the US). Light one and stand about 10 feet away. Now find a pond/lake and have some one light one and drop it in the water about 10 feet away from you while your submerged. If you do try this I'm not responsible for any concusion or hearing damage you recieve. The point is water is an essentially incompressable media. A less drastic experiement. Take three baloons. Fill one with air, one with water, and one with concrete. Put them on a surface that is relativly fragile. Hit each with a hammer with about the same force. The one filled with air will I suspect have little or no affect on the surface. The water filled one will likely show some depression although depending on the surface it may be temporary and the balloon may break. The one filled with concrete will likely have considerable and permanent affects on the surface.

[alecsandros]

Nice imagery, Lee :)

I know sound travels faster under water, but I'm not sure at all about the blast wave. I think the blast wave travels at a lower speed than sound, and it, as a front wave, behaves differently in a dense environment.
Another wave which travels much less in water than through air is light. Turn on a flashlight underwater and it will sprea a cone 4-5 meters. The same flashlight will project light at 12-15 meters trough air.

[Bgile]

Nice imagery, Lee :)

I know sound travels faster under water, but I'm not sure at all about the blast wave. I think the blast wave travels at a lower speed than sound, and it, as a front wave, behaves differently in a dense environment.
Another wave which travels much less in water than through air is light. Turn on a flashlight underwater and it will sprea a cone 4-5 meters. The same flashlight will project light at 12-15 meters trough air.

I don't think that would be true for distilled water, would it? It would certainly be true for water with sediment, and also in a sand storm. But light has different propagation properties than sound does.

[lwd]

The penetration of light in water is very frequency dependent. For some frequencies it is almost opaque for others quite transparent. A different matter entirely from sound. Now again I'm not completely sure what you are calling the "blast wave". Explosions typically produce a shockwave which I believe almost by defintion travels at the speed of sound in that media. Then there's the fact that air is compressable so some of the energy from an explosion in air goes into compressing the media. Some of this energy will come back out but it spreads it out over both time and frequency (some essentially becomes heat). Water being incompressable doesn't produce this effect. On the otherhand moving the water does take considerable energy and if you have an open collum of water a lot of he energy will go into moving the collum up and not be transmitted to the sides of the container. Not being a naval archetect I suspect that which is better to fill the voids will depend a lot on how the TDS is engineered.

[alecsandros]

The penetration of light in water is very frequency dependent. ..

Lee, it's moments like this that make me want to take you out to a bar, get drunk and talk about everything and anything the whole night Steve, you're invited to, if you'd like
Absolutely brilliant post. It's clear I haven't given enough thought to this problem, and that I should do some research.

Btw, is Lee your surname?

[tommy303]

I would recommend this article on underwater explosions and how they work.

http://www.navweaps.com/index_tech/tech-026.htm

[lwd]

... Btw, is Lee your surname?

Yes. I suspect many of these conversations would be much more productive if we could meet in person. A coffee house in a library might even be better than a bar. On the otherhand without the internet we'd more than likely never have run across each other.

[Bgile]

I would recommend this article on underwater explosions and how they work.

http://www.navweaps.com/index_tech/tech-026.htm

I found that confusing. It looked to me like it was saying (in the CAPS part at the end) that an outer void was of no use at all in defending against a contact explosion. In the Iowa class the two outer compartments are liquid filled, but I thought that was determined to be less effective than V-L-L-V as in North Carolina. I wonder also whether the internal belt might have dictated the L-L-V-V layout.

[Bgile]

I like to meet people, but I find that I do my best logic when I have time to refer to references and rewrite things before submitting them.