[Ultra-Tech] What would naval warfare at TL10 look like?

[Daigoro]

Originally Posted by mlangsdorf

I think you may have to work on more reasons why subs aren't the dominate force and surface forces still exist. Quick math against GURPS Vehicle 2nd edition suggests that a sub that carries the same payload and armor as a surface ship has about 4-6% more weight devoted to armor and internal structure, and is slightly more expensive. The sub is going to be 80% as fast with the same power plant as the surface ship. Is that enough to make a difference? I'm not sure.

Coming back to this point...
One of the comments on this article raises a good point. Water surface and air travel are essentially free of obstructions, but submarine travel would have you quite regularly driving through schools of tuna and whale pods, of which you have limited vision or sensor ability to pick up at sufficient maneuvering range. These could surely be alleviated at TL10, but it's not a problem that high-speed surface ships need to worry about.

[Donny Brook]

Based on all of the foregoing discussion, I am of the view that you need to understand the orbital theatre to know what to make of the surface theatre.

[Ulzgoroth]

Originally Posted by Crystalline_Entity

Maybe calling them battleships was wrong, I quite like the idea of warships carrying railguns; would it be more plausible to have a guided-missile frigate armed with railguns in place of guns as a secondary armament?

There's a good likelihood that that's the first place military railguns will be used, seeing as the USN has been working on doing so.

[Phantasm]

Originally Posted by Donny Brook

Based on all of the foregoing discussion, I am of the view that you need to understand the orbital theatre to know what to make of the surface theatre.

Agreed. At present, the orbital theatre is mainly surveillance with the (unconfirmed) threat of (possible) nuclear missile equipped "weather" satellites for orbital strikes. Our late TL8 ICBM, IRBM, and cruise missile arsenals rely on satellite targeting, and I'm pretty sure our autonomous drones have GPS navigation. At TL9, this is not expected to change much.

At late TL9 and into TL10, you also have possible manned spacecraft in orbit that are unable to perform re-entry but are capable of precision orbital strikes on a structure as small as a cabin, and possibly even the low-tech outhouse or porta-potty. Of course, there is also the option of saturated strikes against an area.

[mlangsdorf]

Originally Posted by Daigoro

Vehicles might be out-of-date in that regard. The Russian VA-111 travels up to 9 miles at 200kts at TL7-8

Yeah, the Shkval is one of my reference vehicles for torpedo design. It's a hassle.

VE2 understates the weight/performance of solid fuel rockets at TL6-7, as far as I can tell, but also radically underestimates the performance of TL6-7 torpedoes in general. I'd like to think those two values balance out, but maybe not.

Still, a Shkval has a 5-9 mile range; a Mk 48 torpedo has at least twice the range, a 50% larger warhead, and is 2.5m shorter and presumably lighter. Whether VE2 is exacdly right or not, supercavitating shortens your range a lot and possibly wrecks your stealth during the sprint. I wouldn't bet on a TL10 version of either torpedo getting through an underwater blue-green PD laser array.

[Crystalline_Entity]

Originally Posted by mlangsdorf

Yeah, the Shkval is one of my reference vehicles for torpedo design. It's a hassle.

VE2 understates the weight/performance of solid fuel rockets at TL6-7, as far as I can tell, but also radically underestimates the performance of TL6-7 torpedoes in general. I'd like to think those two values balance out, but maybe not.

Still, a Shkval has a 5-9 mile range; a Mk 48 torpedo has at least twice the range, a 50% larger warhead, and is 2.5m shorter and presumably lighter. Whether VE2 is exacdly right or not, supercavitating shortens your range a lot and possibly wrecks your stealth during the sprint. I wouldn't bet on a TL10 version of either torpedo getting through an underwater blue-green PD laser array.

Just how good would blue-green lasers be underwater? VE2 and Ultra-tech contradict each other here, VE2 stating "A blue-green laser’s 1/2D and Max ranges are halved, but it has the same range underwater as it does in atmosphere" whereas Ultra-Tech is much more restrictive with "The maximum Range can never exceed 150 yards in crystal-clear water, 60 yards in average water, or 15 yards in murky water". I'd have thought that the VE2 laser would be an effective counter-torpedo weapon whereas the Ultra-Tech laser would be pretty pathetic - being able to destroy a torpedo 15 yards away is too close for comfort!

[RogerBW]

Originally Posted by mlangsdorf

Whether VE2 is exacdly right or not, supercavitating shortens your range a lot and possibly wrecks your stealth during the sprint.

Um, yeah.

When you're supercavitating you're making so much noise that you may deafen the enemy sonar operators and/or flood microphones so that it's harder to pinpoint your exact position, but that's the only thing in your favour. It's absolutely not a stealthy weapon.

Originally Posted by Crystalline_Entity

Just how good would blue-green lasers be underwater?

Nobody really knows; they've never been deployed beyond small-scale experiments. Ultra-Tech is more recent than VE so will presumably have been using more recent data.

Current tech is developing counter-torpedo torpedoes; the main problem is ammunition supply. So there's an obvious incentive to get an anti-torpedo laser working.

[Anthony]

Originally Posted by Crystalline_Entity

Just how good would blue-green lasers be underwater?

Poor. At best, use the UT numbers.

[lwcamp]

Originally Posted by Crystalline_Entity

Just how good would blue-green lasers be underwater? VE2 and Ultra-tech contradict each other here, VE2 stating "A blue-green laser’s 1/2D and Max ranges are halved, but it has the same range underwater as it does in atmosphere" whereas Ultra-Tech is much more restrictive with "The maximum Range can never exceed 150 yards in crystal-clear water, 60 yards in average water, or 15 yards in murky water". I'd have thought that the VE2 laser would be an effective counter-torpedo weapon whereas the Ultra-Tech laser would be pretty pathetic - being able to destroy a torpedo 15 yards away is too close for comfort!

In perfectly clear water, you can expect the laser beam to lose half of its power after going through 30 to 80 meters of water (depending on the exact wavelength). So it will be at 1/4 power after 60 to 160 meters, 1/8 power after 90 to 240 meters, and so on. This is based on measured optical scattering of light in water.
http://panoptesv.com/SciFi/LaserDeathRay/Visible.html
If the water has stuff in it, the distance the beam will travel is lower. You can estimate how far the beam will go by figuring out how far you can see before stuff in the water starts to look noticeably dimmed. This is roughly how far the beam will go before it is significantly attenuated.

For example, I was kayaking on the Yakima river today while salmon fishing. I could see the bottom when it was about a meter down, but not at two meters depth. In the Yakima river under those conditions, you could expect the blue-green laser to lose half of its power for every 1 to 2 meters it travels through the water.

In practice, high powered lasers might have worse performance. The threshold for self-focusing and filamentation is significantly lower in water compared to air. A high intensity beam at tight focus (or after undergoing self-focusing) could evaporate the water, forming bubbles that scatter the beam.

If you want a point defense beam weapon for underwater use, consider a high powered sonar beam. This might be able to collapse a super-cavitating bubble (with rather disastrous effects on the high speed torpedo relying on the bubble), and could cause cavitation bubbles when the beam is at tight focus. Cavitation bubbles collapse so violently that they can chew through metal, which would make it useful against non-super-cavitating torpedos.

Luke

[Pomphis]

Originally Posted by mlangsdorf

I think you may have to work on more reasons why subs aren't the dominate force and surface forces still exist. Quick math against GURPS Vehicle 2nd edition suggests that a sub that carries the same payload and armor as a surface ship has about 4-6% more weight devoted to armor and internal structure, and is slightly more expensive. The sub is going to be 80% as fast with the same power plant as the surface ship. Is that enough to make a difference? I'm not sure.

Did you take into account that the sub needs a specific weight of at least 1 to dive ? With all that hangar space with almost no weight you will need a lot of ballast to dive. I once designed a submersible plane, and I had to work a bit to enable it to dive.