Anti naval Rakurai strikes

Otherwise, if it hit - devastating, but if it missed, just a splash. Maybe a large splash, but it's fairly likely that if it misses it will be either to the prow or stern, the two places ships are designed to take big waves from.

Er... the Rakurai strikes is kiloton-to-megaton equivalent. I can't clearly describe the effect of kinetic impactor hitting water, but it would be something more like surface nuclear blast of similar scale. Any sail fleet near the ground zero would be annihilated - they simply burn to ashes, or would be crushed by the shokwave in water.

OrlandoNative wrote:

chrisd wrote:Now when I saw the title to this thread I thought of the "real" (OBS) Rakurai.

That would be REALLY effective against any naval formation, particularly NoG if it could be "provoked".

It should also have a VERY profound effect on the "Loyalist" forces as their own beliefs would suggest that God and Langhorne were against their stance vis-à-vis Charis.

Only if the bombardment packages are very maneuverable. A ship *moves*. A sailing ship may not move in a straight line. Even a steamer can zig and zag. While such a projectile is *very* effective on land because of blast effect - like the old saying, "close" counts for hand grenades, nukes, and kinetic strikes; it would only have that same effect in shallow water at sea. Otherwise, if it hit - devastating, but if it missed, just a splash. Maybe a large splash, but it's fairly likely that if it misses it will be either to the prow or stern, the two places ships are designed to take big waves from.

Ummm, what? I think you need to read up on the shearing effects of a massive shockwave being transmitted through water.

Probably true, but everybody needs to bone up on the effects of surface nudets on ships, for starters [turns out they're not quite as effective as one might think]. And then do a moderately accurate analysis of an OBS projectile impacting in water [which requires a fairly precise knowledge of velocity, mass and cross section, and probably trajectory]

Isilith wrote:

OrlandoNative wrote:Only if the bombardment packages are very maneuverable. A ship *moves*. A sailing ship may not move in a straight line. Even a steamer can zig and zag. While such a projectile is *very* effective on land because of blast effect - like the old saying, "close" counts for hand grenades, nukes, and kinetic strikes; it would only have that same effect in shallow water at sea. Otherwise, if it hit - devastating, but if it missed, just a splash. Maybe a large splash, but it's fairly likely that if it misses it will be either to the prow or stern, the two places ships are designed to take big waves from.

Ummm, what? I think you need to read up on the shearing effects of a massive shockwave being transmitted through water.

OrlandoNative wrote:Only if the bombardment packages are very maneuverable. A ship *moves*. A sailing ship may not move in a straight line. Even a steamer can zig and zag. While such a projectile is *very* effective on land because of blast effect - like the old saying, "close" counts for hand grenades, nukes, and kinetic strikes; it would only have that same effect in shallow water at sea. Otherwise, if it hit - devastating, but if it missed, just a splash. Maybe a large splash, but it's fairly likely that if it misses it will be either to the prow or stern, the two places ships are designed to take big waves from.

Isilith wrote:Ummm, what? I think you need to read up on the shearing effects of a massive shockwave being transmitted through water.

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Louis R wrote:Probably true, but everybody needs to bone up on the effects of surface nudets on ships, for starters [turns out they're not quite as effective as one might think]. And then do a moderately accurate analysis of an OBS projectile impacting in water [which requires a fairly precise knowledge of velocity, mass and cross section, and probably trajectory]

In the description of Armageddon Reef, Merlin says that while Alexandria and its surroundings got hit with six consecutive patterns, the rest of the continent was covered only once.

Also, I suspect that the bombardments aren't purely natural gravity-driven terminal velocity ballistics. They are almost certainly significantly accelerated - either by the launcher or the rounds themselves, and quite possibly both.

Besides, assuming a ship can alter course fast enough to dodge an inbound strike*, it's not going to take the shockwave on it's bow or stern, it's going to be taking the hit on its broadside, even if it doesn't break, it'll be swamped at best, and capsized at worst.


*I sort of doubt that anyone would even try, much less have the time to do succeed. Even assuming an unpowered gravity-driven ballistic from resting in orbit, and you spot it coming over the horizon, you'd still have to realize that it was going to hit your ship and needed to be dodged early enough to pull it off, plus you actually need to successfully complete the maneuver, and move far enough away.



Of course, there's the reasonably good chance that if somebody thinks you're worth taking that kind of shot at, that they aren't going to fire just the once and not follow up on it, so that even if, by some stroke of good fortune, you survive the first shot, you won't be able to dodge all the ones that follow.

Kytheros wrote:*I sort of doubt that anyone would even try, much less have the time to do succeed. Even assuming an unpowered gravity-driven ballistic from resting in orbit, and you spot it coming over the horizon, you'd still have to realize that it was going to hit your ship and needed to be dodged early enough to pull it off, plus you actually need to successfully complete the maneuver, and move far enough away.

And you need to be able to make an accurate prediction about how far from you and on what bearing it will hit before you can start dodging in an appropriate direction and get the ship turned so as to avoid taking the wave broadside. That's not an estimate I expect a typical sailor to be able to make quickly and accurately.

Lesson - if you're sailing in a wooden ship, don't make enemies of people with orbital KEW's....

JeffEngel wrote:if you're sailing in a wooden ship, don't make enemies of people with orbital KEW's....

Aye. Would you mind if I made it my signature?

Of course there's also the question whether anyone would even look in the direction such projectile is coming from. How many people in pre-manned flight times would even expect something hitting them from above? Not to mention the speed such projectile would be travelling at. No offense meant to anyone, but you seem to expect that a person spotting such thing would have time to not only recognize it for what it is, but also actually make any manouevres with wood-and-sail ship. I think what they'd have time for would mostly be thought process along the lines of what's that spot therWHATTHEF- *boom*

Kakai wrote:

JeffEngel wrote:if you're sailing in a wooden ship, don't make enemies of people with orbital KEW's....

Aye. Would you mind if I made it my signature?

Of course there's also the question whether anyone would even look in the direction such projectile is coming from. How many people in pre-manned flight times would even expect something hitting them from above? Not to mention the speed such projectile would be travelling at. No offense meant to anyone, but you seem to expect that a person spotting such thing would have time to not only recognize it for what it is, but also actually make any manouevres with wood-and-sail ship. I think what they'd have time for would mostly be thought process along the lines of what's that spot therWHATTHEF- *boom*

That was pretty much one of my main points.
Although, I'd probably expand it beyond "wood-and-sail" to "pretty much any surface combatant worth the term 'ship'" - there are, after all, physical limitations on how quickly a ship can maneuver, and how extensively it can do so - and the maneuver window isn't really that large.

And, as I said, if somebody thinks you're worth shooting at once, they're probably going to be willing to fire a few more shots if the first one doesn't do the job.

Kytheros wrote:
And, as I said, if somebody thinks you're worth shooting at once, they're probably going to be willing to fire a few more shots if the first one doesn't do the job.

Given how we can all agree that the only people with capability to do so are Merlin and The Temple Thing, I wonder what you would have to do to deserve having hell raining on your ship. I guess the only situation in which Merlin would do something like this would be if the ship was completely crewed by Inqusitors (evil variety) and their lackeys.

I believe the original comment was based on the assumption that the ship[s] being targeted were in combat, maneuvering, and thus not in fully predictable locations - independently of whether they were trying to avoid the shot. Given the vagaries of wind and wave, that's a valid point - nailing a ship at sea dead amidships with anything short of near-lightspeed weapons is a tricky proposition. That it's one that will matter in the end depends on factors that are completely unknown.

People seem to be taking it for granted that the system produces kiloton-range energy releases; there also seems to be a presumption by many of orbital velocities modulated by the acceleration required to de-orbit the impactors. It turns out that the two ideas aren't compatible: you need megatonne impactors for kiloton yields at orbital velocity, or v > 100km/s for impactors smaller than 1000kg. I'm not prepared to rule out big impactors for the original system - that's a chunk of rock under 100m in diameter - but I don't get the impression that the current OBS would use anything that big. OTOH, kiloton-range impacts are not required either by the textev or the purpose of the system. Even a 10t impact would be quite sufficient to, ummm... hammer home the point.

I'm inclined to agree with the speculation that the original OBS was replaced during or after the WATF, and what Merlin and OWL have been looking at can't really be used to estimate its capabilities. It was created for a single purpose - to destroy Alexandria as soon as they gave Langhorne an excuse - and protected by the fact that it wasn't even deployed until it was used. That, especially with the untested deployment and the for all intents and purposes amateur design and construction, makes me think that it may not have been a particularly high-velocity system. Whether they went with a relatively small number of massive impactors or a large number of smaller ones is hard to say, and irrelevant. Either would do the job as a carpet bombing attack, and the extra duration and closely-spaced impacts of the small-impactor scenario might fit the eye-witness accounts better.

To get back to the argument now underway: orbital velocities, if that is the regime the OBS is using, only give Mach numbers of 3-4 in water. That, AFAIK, is a long way from fast enough for water to act like a solid surface in an impact, so much of the energy will be dissipated well below the surface and the shock wave will propagate down as much as out - not quite a 'big splash', but not the same thing as a bomb going off at the surface.

Kytheros wrote:

OrlandoNative wrote:Only if the bombardment packages are very maneuverable. A ship *moves*. A sailing ship may not move in a straight line. Even a steamer can zig and zag. While such a projectile is *very* effective on land because of blast effect - like the old saying, "close" counts for hand grenades, nukes, and kinetic strikes; it would only have that same effect in shallow water at sea. Otherwise, if it hit - devastating, but if it missed, just a splash. Maybe a large splash, but it's fairly likely that if it misses it will be either to the prow or stern, the two places ships are designed to take big waves from.

Isilith wrote:Ummm, what? I think you need to read up on the shearing effects of a massive shockwave being transmitted through water.

Louis R wrote:Probably true, but everybody needs to bone up on the effects of surface nudets on ships, for starters [turns out they're not quite as effective as one might think]. And then do a moderately accurate analysis of an OBS projectile impacting in water [which requires a fairly precise knowledge of velocity, mass and cross section, and probably trajectory]

In the description of Armageddon Reef, Merlin says that while Alexandria and its surroundings got hit with six consecutive patterns, the rest of the continent was covered only once.

Also, I suspect that the bombardments aren't purely natural gravity-driven terminal velocity ballistics. They are almost certainly significantly accelerated - either by the launcher or the rounds themselves, and quite possibly both.

Besides, assuming a ship can alter course fast enough to dodge an inbound strike*, it's not going to take the shockwave on it's bow or stern, it's going to be taking the hit on its broadside, even if it doesn't break, it'll be swamped at best, and capsized at worst.


*I sort of doubt that anyone would even try, much less have the time to do succeed. Even assuming an unpowered gravity-driven ballistic from resting in orbit, and you spot it coming over the horizon, you'd still have to realize that it was going to hit your ship and needed to be dodged early enough to pull it off, plus you actually need to successfully complete the maneuver, and move far enough away.



Of course, there's the reasonably good chance that if somebody thinks you're worth taking that kind of shot at, that they aren't going to fire just the once and not follow up on it, so that even if, by some stroke of good fortune, you survive the first shot, you won't be able to dodge all the ones that follow.[/quote]

Exactly. Unless the velocity is extremely high, the water will splash. As far as wave action goes in deep water, remember tsunamis. They are barely detectable in deep water; the destructive wave occurs when the energy reaches *shallow* water.

Think of naval shells from the old style battleships as a somewhat smaller analogy. If you hit a ship with one, there was serious damage, but ones that missed merely "splashed". Same with bombs dropped from aircraft. Even a 2000 pound bomb dropped into the ocean isn't going to make a wave that's going to damage a ship.

Kinetic weapons damage what they hit *because* their mass is converted to blast effects when they encounter something dense enough vs their velocity to do so. A 2000lb mass hitting solid ground at orbital velocity is going to create significant blast effect. Not so hitting water. Now, if it were moving at or near relativistic speed, that might be different, since then the water *would* act like solid.

To make a difference in a liquid, it's not so much mass as surface or volume. You have to physically *displace* the water - force it to go somewhere else. It's unlikely that any orbital bombardment system would have weapons much over a few yards in diameter. Indeed, it's far more likely to have fairly massive, yet aerodynamically streamlined packages, since those would be easier to have go through the atmosphere without having "drag" affect trajectory or speed.