The THS Spaceship Thread

[Negentropist]

Kitsune, Thank you very much for your kind encouragement. And so:

PRESENTATION BY THE CEO OF VOSPER-BABBAGE:

Thank you all for coming. We've all heard how LSDVs are the wave of the future, that SDVs are dead. Well, I'm here today to drive a stake through that meme's heart.

It is my pleasure to announce the new SDV-90L: SDV Power at an LSDV price.

Observe the display showing a cross-section of our standard SDV-90, with the two heavy 2-space storm shelters highlighted. By simply merging the two into a single, larger shelter, we save 1,222 tons and all this space. Boost the front armor by 27% to match or beat any LSDV’s armor, and we’re still lighter than before.

Now, the SDV-90 can do three things that no LSDV can. First, we can deliver troops to a target to capture it intact, to rescue hostages, for any mission where, as the 20th century space warfare author CJ Cherryh noted, you need a scalpel instead of hammer. So let’s start filling this newfound space with three bunks to let us carry a second squad of troops, an old basic bridge for improved troop command and control – something no other ship offers – and another cabin and two more bunkrooms in case you want to carry VIPs or actually bring home the beings you’ve rescued. An LSDV can blow up a station or merchant ship. We can capture and hold it.

The second thing the SDV-90 can do that no LSDV can is keep on fighting after the first battle. Damage happens – what do you do then? The LSDV-5, LSDV-6, and the Riguang only have five cargo spaces – not much room for fabrication materials or spare parts you can’t make on board. The LSDV-5 and Riguang have antimatter engines, and the latter has a nanocomposite hull. Few shipyards can handle those, and your foe knows where they are, which means he knows where you must go next. The SDV-90 has 75 cargo spaces and a metal-matrix hull – we can always just go deep for self-repair and return at a time and place of our choosing, or dock at any shipyard in the system if necessary. Let’s boost our ability to “take a licking and keep on ticking” – add in a second minifac, a second surgery module with an adjacent additional bunkroom to care for any casualties, and a 5-space hall for morale and troop training on long voyages. An LSDV can fight a battle. We can fight a war.

The third thing the SDV-90 can do that no LSDV can do is fight an LSDV and its AKVs at the same time. We have a 350’ particle accelerator, 12 heavy lasers, and 10 light lasers. Try pitting any LSDV and its AKVs against that kind of firepower. But just to make the battle even more one-sided, we’ve added batteries, so we can now fire all our heavy lasers for 1,125 seconds at the same time we fire our particle accelerator. Game it out. You’ll see that the LSDV runs out of AKVs long before we run out of battery power.

Now, these are very simple changes – nothing affecting drives, hull, or critical systems. It’s available as a quick refit to existing SDV-90s. Yet by reducing their mass by 1,050.4 tons it will boost their acceleration to .108 Gs and their delta-V to 59 mps.

But for new orders, we offer this SDV power at an LSDV price. We do this by taking the refit and replacing the ultralight fuel tanks with light ones. Again – a simple change so you get all the benefits of a proven design with 17 ships of that class already in service. It drops the ship’s price by M$69.8 for a total price of M$740.3. That’s less than the cost of an LSDV-5 without AKVs or a Riguang with three AKVs. And it’s only 6.5% more than an LSDV-6 with its standard four Predator AKVs.

Its performance still beats the original SDV-90. The mass is still reduced by 547.9 tons, so the ship accelerates at .104Gs and its delta-V is 57mps. Its maintenance interval increases to 1.47 hours, making it easier to maintain. And remember that bow armor upgrade.

For those with LSDV-scaled budgets, we recommend the following craft loadout:
- Four inexpensive AKVs, eternally mounted for rapid deployment
- Two Puma MAV boarding craft for troop deployment

I present to you all the SDV-90L: SDV power at an LSDV price!


THS statistics:

New module: 4-space Heavy Storm Shelter. 26.7 spaces, 2, 138.2 tons, $M21.4.

SDV-90L: Variant on SDV-90, THS main book p. 192. Remove the two 2-space heavy storm shelters. Add 15 points of bow armor, one 4-space heavy storm shelter, one cabin, 6 bunkrooms, 1 surgery, 1 minifac, 1 old basic bridge, ½ hall (5 spaces), and 1 battery. Change all 750 spaces of fuel tanks from ultralight to light. Reduces all Mass by 547.9 (CMass to 14,368.1), total ship cost $M740.3, sAccel 0.104Gs, Delta-V: 57 mps. Burn endurance: 50 hours.

[Kitsune]

Nice. By the way, even the battery pack alone is a good idea for a mini-update of every SDV-90. I understand that one space of battery should be able to power the ten light lasers of a Resolution/Gram class ship for 18 combat rounds - and enable it this way to use all its weapons and primary sensor systems at the same time for that duration. Effective stats are unaffected except for cargo space, which is reduced by 5 tons, and cost, which goes up by M$ 0.75. Which seems to be an acceptable trade. I included this as well in the SDV-90U design.

[Negentropist]

I would like to make some further enhancements to my SDV-90L design, and retcon them into the announcement from earlier in this thread.

To recap the story so far: The cheaper LSDVs are considered the wave of the future. They let more groups enter the campaign, and two LSDVs can flank a single SDV.

My SDV-90L design assumes that Vosper-Babbage, maker of the SDV-90 (THS core rulebook, p. 192), reacts by modifying its proven (i.e. fully debugged) SDV-90 design to make it price-competitive with the LSDVs listed in the THS book “Spacecraft of the Solar System.” In order to keep the marketing points of “proven design” and “maintainability”, no nanocomposites, antimatter, or elements needing debugging (e.g. new engine designs) were allowed.

The previously-posted design combined the SDV-90’s two heavy storm shelters into one 4-space shelter. This saved enough mass to upgrade the bow armor to 70/20F and replace the Ultralight fuel tanks with Light, bringing the price below the LSDV-5 and not too far above the Chinese LSDV. It also saved enough space to improve crew living conditions and add a battery that let all weapons fire in combat.

I would like to suggest some more changes that further enhance the SDV-90L’s attractiveness vs. the various LSDVs.

First, those 10 light lasers are utterly worthless in combat. At short or effective range they each do 2Dx5 damage, making them unable to penetrate a warship’s bow armor. Replace them with coilguns (which fit into the space), saving 40MW and almost $M20. No additional munitions packs are needed because the ship already carries 27 of them, and one doesn’t need many 11-gun broadsides to end a battle.

Second, yank the engines and replace them with the engines from the DFS-3, a craft that has the same size and about the same mass as the SDV-90. Which means that the SDV-90L will have performance comparable with the DFS3 and most LSDV offerings – and you’re still using a fully-debugged design component. The reduction of engine size from 375 to 250 spaces also lets you cut the retracting radiator wings by 62 ksf. Saving from engine and radiators: $M81, 156 spaces, and 810 tons.

Third, these changes create an energy shortfall of 85MW/turn. One battery pack will cover this for ten turns – more if the ship is not engaged from all sides.

Fourth, fill the vacated room with 150 spaces of fuel tank (light not ultralight, remember) and increase the rec hall by 5 spaces.

Finally, there is no reason to have the stern armored to 16cDR. Cut off 11 of that and add it to the bow. Bow armor is now 81/50F. Yes, 50F, which means that it can go head-to-head with the more-than-triple-the-price, two-beam DFS-3 and come out ahead in the radiation department.

Total price: $M650.9 – cheaper than the Chinese LSDV, yet far deadlier. sAccel is .07Gs, and delta-V is 68mps. Maintenance interval is 1.57 hours.

Definitely “SDV power at an LSDV price.”