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Old 12-20-2014, 09:32 PM   #10
BraselC5048
 
Join Date: Oct 2012
Default Re: Linear shaped charge to cut through DR 1900?

Quote:
Originally Posted by Rysith View Post
That argues (especially since weight and time aren't that much of an issue) for a secondary anti-personnel charge as part of the breaching procedure - set off the breaching charge and then set off the in-setting equivalent of a giant claymore mine. That should help with establishing a foothold in the enemy ship, at least.
It's modern militaries. Everybody and his brother on the starship you're boarding is covered with DR 16-18 body armor everywhere except the head (DR 15 all-round ballistic plastic vacc suit bubble helmet), hands and feet (no DR). A claymore would likely cause no wounds at all. The best option is a enhanced fragmentation round from a 105mm ish weapon (pack howitzer or recoilless rifle, depending on the navy) set to airburst by a simple time fuze. Then there's the problem that everybody is likely behind barricades (think low walls, 5 ft high) including a DR 75 spare hull plate, with a LMG on a bipod on top, or a HMG on a tripod behind it. And the whole "vacuum greatly reduces the effective radius of explosive damage" issue. I once tried clearing an entrance by firing through the (oversized) airlock a HE bombardment missile, 2 tons of HE filler with a yield of 4 tons. It didn't work nearly as well as I hoped, although I also forgot completely about fragmentation damage, which might have driven the casualty care up. Basically the MG positions were on the sides of the cargo bay behind the airlock, and I expected them to be in the center, not that there was any choice of target area anyway.

Still, that is a consideration for both sides. The one time I defended against a boarding action, although also driven by it being a forward airlock with nothing more than a hallway behind it, I set up the MG positions firing down both corridors out of the 20ft ish long corridor straight back from the airlock, with no coverage of the entrance itself. Thee bridge was right behind one of them, they rushed it, and overran it, not helped by using bad Malf rules (since replaced) that had the MG jam after a few shots.

Quote:
Originally Posted by Anthony View Post
The problem with comparing with a single shaped charge is that you want to make a linear cut, not a narrow hole, so you multiply the weight by the length of the desired cut. Looking at UT, a 100m shaped charge or HEMP round will blow through DR 1900, but it probably only makes a 1" hole, so you need 12 of them per foot...

In the end, you're talking armor thicknesses where no-one is going to try to cut through them. They'll figure out how to bypass them, or if they don't need whatever is behind the door intact they'll just fire an APEX missile through it.
I actually scaled from the closest thing I could find, which is a flexible rope linear shaped charge in High Tech - actually the same thing I'm designing. So it's actually scaled from a linear shaped charge already. The difference is that High Tech's is a 20 ft spool of flexible cord that weights half a pound per foot, and mine comes in rigid 1 foot sections that weight 20 pounds each. Much heavier, 40 times in fact, and enough to blow a man-sized opening isn't portable - but it isn't intended to be. You simply have guys carry them to the airlock on your own ship, likely several guys, while 1-2 men actually place them while they're being supplied. Wouldn't work under fire, but you're not under fire. And my tech level is 8 + a bit of ^, and just about any equipment from Ultra Tech would be more advanced then what the campaign allows. I'm using technology from High Tech for the most part.

And the armor is proof against every weapon in the starship's storerooms. Not proof against the ship's weapons, but sometimes you have to board, and in a jump point ambush, where it takes 8 minutes for the second (or later) ship coming out of jump to get its drives working and lasers charged enough to go through your own armor at all, and your ship is capable of 6 G's and they're only 1000 km away, and they haven't had time to depressurize their hull, and it'll be almost as long for your own lasers to charge...

I actually ordered a boarding action against an enemy cruiser in exactly that bad spot. I also had the advantage of having just recalled the boats loaded with a total boarding party the size of their entire complement, so I had 170 men already armed and assembled for boarding, only needed to go up a flight of stairs. Never knew what hit them.

My defending was when my character was only a lieutenant, we were in a similar position, and a laser salvo to the bridge and common areas resulted it 3/4th of the crew being either dead, wounded or stuck without a vacc suit in a pressurized compartment with vacuum outside. I wound up winning the Medal of Honor (actually the SEH, it was a traveller setting run without GURPS: Traveller. Someday I'll release it as Traveller - 1750) for single-handedly defending the starboard stairwell against 17 marines, and therefore keeping them contained to a small area at the bow on one deck. Also personally accounted for half the boarding party being casualties, although some of that was done with others. The rest of our squadron was winning by weight of numbers, and they pulled out, and jumped away.

Any interest in me writing up a recap of that short action and putting it in a thread? The dice were rolling really hot that day, with tons of hits being rolled up as neck.
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