"Naval Theory and Wargaming" Topic

Interesting read.

Have you painted any of the WTJ 3D print models yet?
Do they take paint/primer well?

The shapeways fud/best models have wax filling in some of the stairsteps, making them smoother but paint doesn't take well.

I see WTJ discuss this. At least with Shapeways I find it difficult to remove the wax. I've warm soapy warm, Simplegreen, soft toothbrush, repeat and still the paint won't stick.

Dragon>
Have you used primer as well? I know that prototype materials are more delicate than resin cast, but consider using Dawn and a plastic bristle in a Dremel on low. Be very careful!!!!

QC> Good read, but I think it all comes down to personal preferences, thus the plethora of games out there. I have played games that are limited in realism, but are more fun than some that are true to life.

QC the Shapeways FUD are transparent, just as the WTJ models are. As I said WTJ uses wax for filler also.

Yes I primed them. Paint sticks, at first, later it just sloughs off as does the primer. It has been suggested that Bestine removes all the wax leaving a good painting surface, if rougher, as the wax filler is removed.

WTJ advises against that. They agree it makes an excellent painting surface but the 3D print becomes brittle.

My current experiment is painting the models with a 50-50 water Future acrylic floor wax. I think this might work but I haven't primed them yet.

Neat article, interesting thoughts and a good summary.

-Will

Interesting thoughts, QC. BTW, regarding the theoretical advantage that WWII fire control radar gives the attacker, I don't think it becomes overwhelming until 1944, if then. Fortunately, most of the interesting WWII surface actions occur prior to 1944.

See "Blutarski's" comments near the bottom of this thread: TMP link

A published source covering the difference between theoretical actual 1942-1943 radar-controlled gunnery, which paints a similar picture, is one of Captain Crenshaw's books; i.e."South Pacific Destroyer" and "The Battle of Tassafaronga".

WTJ advises against that. They agree it makes an excellent painting surface but the 3D print becomes brittle.

Dragon6, my personal experience with Shapeways is that Bestine *doesn't* noticably affect the strength of their printouts.

Mark

I read a naval oriented book years ago, when I was playing Harpoon, and I found that many of the tactics apply to space games as well.

Called "Fleet Tactics", here:
amazon.com/Fleet-Tactics-Practice-Wayne-Hughes/dp/0870215582

As far as your last question goes, "The question is – what is more fun to play? Trashing a ship or two every turn, or wearing ships down over several turns of maneuvering so that they are forced to disengage or even blow up?"

I think that the more generally realistic decision for duels to squadron engagements is wearing ships down.

But if you're going to do whole fleets of ships, you will need to shift to the 'ship blows up' style of game, just to keep things moving at a reasonable pace.

Very interesting and thought out blog post, so much so that I'll bite!

Regarding the tactics of concentrating fire, I really think it should be different in space combat than in late XIXth to mid XXth naval actions. Laser fire and computer guided target designation should work differently than naval shells and optical telemetry. Furthermore, instead of making it more complicated, one can imagine that concentrating fire may make a target easier to hit by every ship of a space squadron. I'm a naval fan, but also an avide Battletech player, and in that game, you have a decice that is called C3. C3 is a network that allows each linked unit to determine its range bracket from the position of the unit closest to the target, so if you have 1 ship at say, 2 hexes from the target and the remaining ones at 10, everyone would be considered firing from 2 hexes. Of course, since this is very powerful, Battletech ahs some restrictions to C3, and you can easily design your own in order to balance it out.

Will add this from the semi-porno but well thought out SF series "Spaceways": Space combat is the reverse of sailing vessel fighting, because of two things – speed and weapons aspect.

At high velocities, you cannot be sure of a shot hitting with any weapon unless the target is bearing forward. Passing angles make a hit unreliable due to time on target for beams, angle of hit for projectiles, etc. So, the majority of weapons are mounted to fire forwards, rather than at angles from the line of the craft's major direction axis of movement.

For this reason, and the speeds involved, the tactic of "Crossing The T" is utilized but in reverse; The target is forced into or your ship is directed into a position where the target crosses the top of the T the main stem being your trajectory. Projectile weapons are fired just as the target approaches 'dead ahead' to give a better chance of hit, and heat -seeking weapons get a longer opportunity time to lock onto exhausts. Beam weapons if timed right basically 'rake' the target as it passes using the target's own movement to spread damage.

I think the critical issue is the firing weapon itself – lasers will have instantaneous speed and nearly always hit unless the relative motion variables are totally off the chart. Of more interest are "newtonian" weapons like guns, torpedoes, missiles, that use old-fashioned means to hit. Probably the guns will be small-caliber railguns, but they'd still "shoot" a projectile that is totally "stupid" without guidance, or perhaps only a bit dumb, so it can't be "fooled" by ECM. However, it will become very hard to hit with longer ranges and relative motion difficulties.

Attack Vector Tactical uses railgun volleys to force the opponent to maneuver into your laser arcs. AV:T uses really big laser mirrors but at relatively low frequency, which makes for rather short-ranged lasers (the lower the frequency, the wider the dispersion, all other factors equal)

If AV:T ships were using 200nm UV lasers instead of 1200nm infrared lasers, laser engagement ranges would be a LOT farther. About 6x farther, in fact.

For this reason, and the speeds involved, the tactic of "Crossing The T" is utilized but in reverse; The target is forced into or your ship is directed into a position where the target crosses the top of the T the main stem being your trajectory. Projectile weapons are fired just as the target approaches 'dead ahead' to give a better chance of hit, and heat -seeking weapons get a longer opportunity time to lock onto exhausts.

Except that there's not much additional target-solution complexity to mounting kinetic launchers into turrets. I mean, the US figured that out prior to WW2 with mechanical computers. And fitted a pretty sophisticated crossing-target computer system into the B29, because the gun-sights were not in the same place as their guns.

It's worth mentioning that seeker slugs will have about the same prediction issues as dumb kinetics, the only difference being that seekers will have some delta-vee of their own to give a little more margin-of-error in your sighting.

Beam weapons if timed right basically 'rake' the target as it passes using the target's own movement to spread damage.

Depends on how much energy you're delivering and how fast it gets delivered. A 10megawatt X-ray laser bouncing off a 1m diameter mirror is a ravening death-beam at distances measured in light-minutes. ( link ) At one light-minute, the beam spot size is 30cm, and will take a few microseconds to burn through 4cm of graphite (or reinforced carbon-carbon).

Now, that's a beam incapable of firing into an atmosphere, it's dang near gamma radiation, not Xrays. A similar beam that's "merely" a 200nm UV laser (on the dividing line between UVC and Extreme UV, so barely atmosphere-capable) will have a range 1/10,000 of that ravening deathbeam. Since one lightminute is roughly 18,000,000,000 meters, that UV laser will be a devastating weapon at roughly 1,800km. Amazing how fast your engagement ranges go to hell when you increase your wavelength, isn't it?

That's why the long-ranged weapons of a combat spaceship will be guided missiles. Because of the relatively slow speed (basically the same as their launching ship), I prefer to use the word 'torpedo'. But that's a different discussion.

Dumb kinetics will have a very short range due to their dispersion. Assuming dispersion similar to good-quality modern firearms, you're looking at a dispersion of 0.015 mils, 15cm at 1km. Assuming a 10m diameter target ship, your engagement range is going to be ~67km. A 1m diameter incoming missile could be hard-killed with kinetics at about 6-7km. Note that I'm keeping the dumb slug within the diameter of the target, because nobody wants to be that guy who leaves 'presents' for non-combatants to run into in the future!!!

(For the record, I assume rather large ships ~100m across their shortest aspect, so "can't miss" engagement ranges are on the order of 700km)

I sense that these armament discussions tend to leave off engineering limitations. There are a number of reasons for beam weapons having effectively short ranges:

* Beam spread. I don't really buy into a weapon having only 1 ft spread at light-minutes distance.

* Target acquisition. You know he's out there, right there on your scope. But knowing where to the nearest 1000 ft, an actionable accuracy?

* Weapon aiming. If a turreted weapon there are a lot of places where there is inaccuracy. Play in the gears; lack of synchronization between the systems (remember the Gemini splashdown where they were off target because the "day" was programmed into Gemini as 24 hours, rather than the exact time to the millisecond?); not being recently bore-sighted, ship vibration causing shimmy and the beam water-hosing all over the place; Differential heating causing mechanical distortion (things get crooked).

* Maneuver. Besides causing vibration and the other things, the ship might move just after the firing calculation was made but before the shot is taken. Think of biathlon shooters who wait between heartbeats.

All in all, how far can your ship accurately shoot a beam weapon? It's your guess.

* Beam spread. I don't really buy into a weapon having only 1 ft spread at light-minutes distance.

It does seem really absurd, but that's what the math says that the beam spread for an X-ray laser is.

Beam spread for lower frequencies is significantly greater. Lasers spread very little in general because every single photon is polarized and in phase, but visible light lasers that we're used to have a much larger beam spread. I pulled that obscene x-ray laser from Atomic Rockets ( link ), and the formulas to do the math yourself are also on Atomic Rockets ( link , repeating it here for convenience):

Beam Radius at target = 0.61 * range to target * (beam wavelength / emitter mirror radius), with all numbers in meters.

So, a lightsecond is 300,000,000m, xray laser beam wavelength is 1.4E-11m, and the emitter mirror from the example is 1m in diameter (0.5m radius).

0.61x300,000,000x(0.000000000014/0.5)=0.005124m, spot size of 5.124mm at one lightsecond. Checks with example.

Lightminute is 18,000,000,000m, all other numbers stay the same:

0.61x18,000,000,000x(0.000000000014/0.5)=0.30744m, spot size of 30.744cm at one lightminute. Also checks with example.

Now, let's bring that laser freq down to a number we can actually see, blue-purple at 400nm wavelength (4E-7m), at one lightsecond range with an emitter mirror 1m in diameter (basically, same as that first example but with a visible laser beam):

0.61x300,000,000x(0.0000004/0.5)=146.4m. One hundred forty-six point four meters in diameter at one lightsecond. That's not going to do a bit of damage, not even at 10 megawatts beam energy. I actually own a 100milliwatt blue-purple laser pointer.

What about one of those green lasers? Green is 550nm wavelength, so the formula looks like this:

0.61x300,000,000x(0.00000055/0.5)=201.3m beam diameter at one lightsecond.

Red? 725nm wavelength, so:

0.61x300,000,000x(0.000000725/0.5)=265.35m beam diameter at one lightsecond.

I told you that visible frequencies have much greater beam dispersion than that unholy xray laser!

This also means that xray lasers are going to be unlikely weapons in space BECAUSE of their stupendous range. It'd suck to have an energy-weapons-only fight that blows the hell out of un-intended targets on the far side of the engagement.

* Target acquisition. You know he's out there, right there on your scope. But knowing where to the nearest 1000 ft, an actionable accuracy?

Given that the primary detection will be some species of optical (probably thermal with backup visible light), that's not all that hard. A 'standard' riflescope has 1/4 minute-of-angle adjustment clicks, so one click is 1/4" at 100 yards. At 4800 yards, I know where the edges of your ship are to within 1 foot, so even with 1/4moa accuracy, I will know your position to the nearest 1000ft at 4,800,000 yards (4,389km).

Most optical instruments are significantly more precise than that. Hubble, for example, is capable of making measurements accurate to within 0.0003 arcseconds (and that's with the bad mirror!). An arc-second is 1/60 of a minute of angle, so Hubble is able to tell your position within 1000ft at 219,450,000km (1/4moa is 15arcsec, and 0.0003arcsec is 1/50,000 of 15arcsec).

At a little over 12 lightminutes range, I can tell your position to within 1000ft using Hubble-sized optics.

So yeah, I can tell where you are precisely enough to hit you with a laser beam at any range the laser will pack enough energy density to harm you.

* Weapon aiming. If a turreted weapon there are a lot of places where there is inaccuracy. Play in the gears; lack of synchronization between the systems (remember the Gemini splashdown where they were off target because the "day" was programmed into Gemini as 24 hours, rather than the exact time to the millisecond?); not being recently bore-sighted, ship vibration causing shimmy and the beam water-hosing all over the place; Differential heating causing mechanical distortion (things get crooked).

Check out the precision of the Hubble Space Telescope, and remember that Hubble is 1970s tech. Measurements accurate to within 0.0003 arcseconds, and able to precisely image objects roughly 0.1 arcseconds in size. One arcsecond is 4.848(continuing) millionths of a radian, so at 1000km the hubble can see and precisely point at a target that is .4848m in diameter. 48.5cm target, and the laser can be precisely focused on it at 1000km.

* Maneuver. Besides causing vibration and the other things, the ship might move just after the firing calculation was made but before the shot is taken. Think of biathlon shooters who wait between heartbeats.

True, but that is something that ends up getting known in the process of eyeballing the target. Or do you think that the fire control computer on the Abrams doesn't keep track of the tank's movement in 5 dimensions (3d plus two angles of cant between tangents to the earth's surface at 90deg to each other) between the time the target is lased and the trigger pulled? The Army publicly admits that the Abrams fire control software updates 30 times a second with range to target, own-tank movement, and cant angle.

While I might desire a more frequent update for a spaceship, 30 updates per second will make any one position change physically impossible to be greater than 10,000km because that's how far light would travel in 1/30 of a second. Since even interplanetary speed are such a small fraction of cee that it's meaningless to express them that way, because a 'slow-boat' doing the Earth-Mars trip via Hohmann transfer orbits is moving at 6.12km/sec relative to Earth. Let's double that speed for the worst-case scenario for the attacker to 12.24km/s. In 1/30 of a second, the oncoming target will travel 408m relative to my ship going the opposite direction. Guess I need to speed up the re-calculate rate for my firing solutions to keep my knowledge of your position to within 1000ft. OK, I will update 100x a second (yeah, decimal time!), so the oncoming Mars-bound target will travel 122.4m or a little over 400 feet per update.

Though I should mention that if we start getting into drives capable of brachistchrone badassery (aka continuous acceleration), the delta-v and therefore closing speed goes up massively. Still doing the Earth-Mars and vice-versa routing, you're looking at closing speeds on the order of 400kps if your drive is a wimp and can only burn at 0.01gee (continuous acceleration of ~1m/s/s, from link ). That's getting into needing much faster targeting updates, roughly 1334x a second to keep the target's position fixed to within 300m. But modern computers can handle that without breaking a sweat, what with clock speeds in the gigahertz range.

So no, I'm not getting into anything too crazy or out of the realm of the possible.