using spaceships for battletech-style tactical mecha combat

[AlexanderHowl]

Had the Germans invested in aircraft carriers rather than battleships early in WWII, their navy may have been more effective against the Royal Navy. As it was, they never really completed any proper aircraft carriers. Conversely, the Royal Navy and the USA had dozens each. Then again, the Germans never really cared much for ships, as they only had nineteen capital ships.

If Germany had, instead of producing its four battleships before WWII, had gone with eight aircraft carriers (which would have been around the same cost), they would have likely been much more effective as a naval power. At that point, they could have fielded 640 aircraft on the high seas, which could have caused the Royal Navy some concern. If they were each escorted by a capital ship, four destroyers, and a dozen submarines, they could have packed quite a punch.

When it comes to spacecraft, however, long range beam weapons, backed by VRF beam weapon turrets for point defense, seem to be a superior solution. If you can damage your opponent from 100,000 miles away, it will likely take their fighters/missiles hours to reach you (assuming that they can maneuver enough to reach you). Smaller spacecraft can provide additional screening against fighters and/or missiles, but the point defense of the large capital ships should be sufficient to engage thirty to sixty groups of targets per turn.

[Rupert]

Originally Posted by AlexanderHowl

Had the Germans invested in aircraft carriers rather than battleships early in WWII, their navy may have been more effective against the Royal Navy. As it was, they never really completed any proper aircraft carriers.

At doing what? They'd be no more likely to get out into the Atlantic than any other capital ship, and are actually easier to sink than battleships. Also, until 1940 at the absolute earliest carrier aviation was awful and doing much of anything, except possibly scouting, so why would they have built big fast carriers?

Bear in mind that the big fast carriers that the US, Japan, and the UK had were accidents of history, and only existed because those navies wanted to not have wasted all the money they'd spent on half-built battlecruiser hulls, so their conversion to carriers was written into the treaty.

Conversely, the Royal Navy and the USA had dozens each. Then again, the Germans never really cared much for ships, as they only had nineteen capital ships.

They had four. Two Scharnhorst-class battleships (or battlecruisers, depending on who you ask), of roughly 'treaty' displacement, and two Bismarck-class fast battleships of well over treaty displacement. Cruisers are not capital ships in the real world, no matter what computer games think.

If Germany had, instead of producing its four battleships before WWII, had gone with eight aircraft carriers (which would have been around the same cost), they would have likely been much more effective as a naval power. At that point, they could have fielded 640 aircraft on the high seas, which could have caused the Royal Navy some concern. If they were each escorted by a capital ship, four destroyers, and a dozen submarines, they could have packed quite a punch.

I think you seriously under-estimate the cost of a carrier and its air group. You also don't seem to realise that running subs with your surface fleet is a good way to get you subs sunk by your own surface ships by accident, and if your escorts are ordered not to attack subs, well that's going to go badly too.

Given what was known at the time, battleships were a necessary investment for the major powers until at least 1940. The continued construction of new battleships after then (especially HMS Vanguard), and the complete refurbishment of those sunk at Pearl Harbour was questionable, but earlier construction made sense at the time.

[AlexanderHowl]

While the cruisers would have normally not been considered capital ships, they were pretty much used as such by the Germans, so I included them in the number (though major ships may have been a better word choice). After all, the Germans were too terrified of losing their battleships to use them as anything but commerce raiding, which could have been done by smaller ships, so they had to depend on the cruisers. The heavy cruisers, cruisers, and light cruisers had to pick up the slack for the Germans.

Of course, it is difficult to generalize the utility of warships to the utility of military spacecraft. In space, everyone can see everyone else, so no one is hiding beyond the horizon. Firing distance and accuracy matters, and the ship that can land the most penetrating hits from the furthest distance is usually the ship that survives. Thus, beam weapons usually end up being the replacement for fighters/missles, as they can engage at extremely long ranges. Heck, beam weapon exchanges can potentially decide a battle hours before any missiles or fighters would become a factor.

[johndallman]

Originally Posted by AlexanderHowl

The heavy cruisers, cruisers, and light cruisers had to pick up the slack for the Germans.

May I ask which operations and actions you're thinking of here? The Kreigmarine's assorted cruisers seem to have done fairly normal cruiser missions until they were disabled or relegated to training duties.

[ericthered]

Originally Posted by Rupert

Historically it's about right. Using Spaceships you're getting shells that are much faster than historical ones, which would be hitting at 1/2 a mile per second and less. Yes, they'd count as AP, but they would also often be at 1/2D range or more.

DR785 will protect against 112d(2), which is a SS 30cm shell at 1/2 mps muzzle velocity at 1/2D range.

It's in the right ballpark.

Originally Posted by ericthered

I don't have Doug's sheet (I need to get my hands on it one of these days), but when I crunched the numbers in high tech a while back the higher-velocity weapons generally did their dice of damage equal to their caliber in mm. A 12 inch/ 30 cm shell in high tech with the high velocity guns should do around 300d of damage. 150d(2) is enough to get through the armor without much fuss.

Originally Posted by Fred Brackin

Are you referring to the weapon design rules in Ve2? Those will give you basically accurate figures for KE damage either for 3e or 4e. Explosive damage (but probably not HEAT) would need to be refigured for 4e. That did change. ACC is vary different for 4e. Range was always a little problematic for Ve2 when dealing with large indirect fire weapons.

I just did some very informative reading and calculating in vehicles (2e) with weapons, which has some interesting numbers to go with my earlier observation about high-velocity gurps weapons doing damage equal to their caliber in mm. I think the 3e barrel length modifiers may have gone up a touch in 4e weapons, but its a small effect. The 13.5 inch shells are doing 253 dice of damage, while the "fast" 12 inch shells are doing 270 dice of damage, if I use the long barrel numbers.

So that leaves the following:

• Is using the half-damage range representative of the actual speeds that naval shells hit their targets at a distance? Do the shells slow down that much in flight?
• Could point-blank fire directly to the belt armor actually penetrate it? Could the Queen Elizabeth class take those 13.5 inch shells?
• Does the damage inflicted by the dice show the correct amount of penetration into the ship's armor, given the numbers we were throwing around earlier?

[Anthony]

Originally Posted by AlexanderHowl

Had the Germans invested in aircraft carriers rather than battleships early in WWII, their navy may have been more effective against the Royal Navy. As it was, they never really completed any proper aircraft carriers. Conversely, the Royal Navy and the USA had dozens each. Then again, the Germans never really cared much for ships, as they only had nineteen capital ships.

Honestly, that was 19 more capital ships than they needed. Naval forces aren't really something to go halfway on, either build enough to win or just build enough to keep the enemy honest (which doesn't require capital ships).

[Rupert]

Originally Posted by ericthered

I just did some very informative reading and calculating in vehicles (2e) with weapons, which has some interesting numbers to go with my earlier observation about high-velocity gurps weapons doing damage equal to their caliber in mm. I think the 3e barrel length modifiers may have gone up a touch in 4e weapons, but its a small effect. The 13.5 inch shells are doing 253 dice of damage, while the "fast" 12 inch shells are doing 270 dice of damage, if I use the long barrel numbers.

I don't think any of the big battleship guns should count as 'long' barrelled. The sidebar "How Long is My Barrel?" (VE2, p.99) gives 'medium' as 40-59 calibres, which includes all the big guns of the period.

Well, if we look at the stats for a 13.5" gun at http://navweaps.com, the muzzle velocity for a new gun firing a 1,400 lb shell was about 2,500 ft/s. Assuming the shell worked as intended (and they often didn't, due to design and manufacturing flaws that were corrected by the War's end), that would be sufficient to penetrate 17.3" of armour hit square on. At 10,000 yards, velocity would be 1850 ft/s and penetration 12.5" if hit square. At 15,000 yards it's lost another couple of hundred feet per second, and is landing at a definite angle.

The thing is, plates were very seldom hit square on. The shell would be coming in at an angle due to range, the target would be rolling, and the target would almost never be exactly broadside on (though turret faces would often be very nearly square), and often the armour was sloped as well. Sometimes these factors cancelled out, but more often they did not. Thus even if the gun and shell worked perfectly and the gun wasn't worn, operating at a lower temperature, etc., the chances of penetration being as good in a real battle as on the range were slim.

That said, once ranges get down to a mile or two and gunnery becomes 'point and shoot' (in GURPS terms using Gunnery rather than Artillery) those big battleship guns had far more penetration than they needed to penetrate belts, assuming they hit roughly square.

[Rupert]

Originally Posted by Anthony

Honestly, that was 19 more capital ships than they needed. Naval forces aren't really something to go halfway on, either build enough to win or just build enough to keep the enemy honest (which doesn't require capital ships).

It sort of does, actually. If the Germans hadn't had any capital ships, but only cruisers, available to attack the arctic convoys the RN wouldn't have needed to provide them with battleship escorts and could've used those battleships elsewhere, and they had plenty of other places they needed them.

Likewise, the existence of the Italian battleships in the Mediterranean somewhat limited the RN's freedom of action.

[ericthered]

Originally Posted by Rupert

The thing is, plates were very seldom hit square on. The shell would be coming in at an angle due to range, the target would be rolling, and the target would almost never be exactly broadside on (though turret faces would often be very nearly square), and often the armour was sloped as well. Sometimes these factors cancelled out, but more often they did not. Thus even if the gun and shell worked perfectly and the gun wasn't worn, operating at a lower temperature, etc., the chances of penetration being as good in a real battle as on the range were slim.
.

Is that reflected in the numbers we've been discussing? It sounds like many measurements for armor penetration are assuming square hits, which is the best possible scenario.

[AlexanderHowl]

A square hit would probably be best represented by maximum damage while a glancing hit would probably be best represented by minimum damage, with any damage in between representing an increasingly angled hit.