The problem with using pitch and yaw to attempt to dislodge boarders is that the boarders and boarded ship can effectively become a closed system and when the captain goes into a death spin the boarder also goes into the same death spin. The nature of artificial gravity will doubtless have an effect on this, but I'm not certain we can write off boarding that easily. I doubt that starships would be made with high thrust capability in all ranges of motion, it would be a waste. .01G thrust in any direction would be enough to orient the main thrusters of the ship in any direction the ship's captain might require pretty quick. Some streamlined ships might have more non-main-thruster power if they rely on thrusters to change orientation inside a gravity well but outside a gravity well all that is needed is a minimal amount of force to change the orientation so the main thruster is pointed where you want to go. CG thrusters (however they work) would be a problem, if they are orientationless in which case the ship could twist off boarders.
Boarding Actions: Do those really happen?
- Thread starter Shadowfax
- Start date
far-trader
SOC-14 10K
You misunderstood, it's not to dislodge but to make it impossible to even get close in the first place. As you attempt to close the target ship simply introduces another twist in their x,y,z and you not only can't connect but risk being slammed by the ship. I wager a good pilot might even be able to bring a hard part of their ship to strike a more vulnerable part of yours if you're foolish enough to try boarding when they have any maneuver left at all.
Once linked yes, but even then your connection had better be solid or it'll tear off with damage done to one or both ships in the bargain. And by solid I mean hull material intimately connected solid. It would be nothing less than an external docking cradle large enough for one ship or the other. That's a lot of dtons and Cr for something of limited use unless it was a design feature of the ship in some legit capacity. Like drop tanks or cargo cans.
Not in mtu (it's limited to within the hull, otherwise you'd get all kinds of weirdness).
Nope, still no sale here
As you note you don't need a lot of thrust to do a quick reorient, now add a quick tap of the main thruster anywhere in that reorient and I don't think you want to try to dock with that. To be clear I don't think you want to even be close to that and docking with it will be impossible. I don't care what TL or fancy calculations you run or how much more maneuver capability you have than they do, you just can't anticipate or match an active ship's desire to not be caught. Period. Your only chance is if their maneuver is out of the question. And even then you will have a devil of a time matching their vector if it's more than two axis, mathematically impossible I think*. Your option becomes one of merge (i.e. collide) with the body and make the motion a combination (i.e. a single system) then use your own maneuver to stop the tumble, if you want to. Once you've merged you can proceed to board, but such a merge in my opinion is not going to get a nice airlock to airlock dock. You'll be lucky if you only have to cut an access into their hull and not out of your own to get there. And you'll still need some way to quickly and solidly attach your hull to thiers at the moment of collision or you'll just be going off in different directions again.* but if anyone can show the work one way or the other it'll settle that part of it
It would still depend on the agility of the ship in question.
To put it simply, if it has the agility of a supertanker, boarding should be no
problem at all, because all movements of the ship except in the direction of
the main thrust would be very slow and far below 1 G - unless is was built
with normal maneuver drives for position control purposes, which I would
consider unlikely.
On the other hand, if it has the agility of a helicopter or jet fighter, boarding
would doubtless be impossible.
Almost all ships will be somewhere in between these extremes, and where on
this scale they are would determine whether they can be boarded or not.
In Traveller 'reality' - none
In a game for the purposes of telling a story - as many as you want
Gents,
Mike, quite naturally, has put his finger on the crux of the issue. Realistically, opposed boarding actions should be rare to the point of vanishing. In the game however, boarding actions should occur whenever the GM needs them to do so.
IMTU, the HG2 boarding requirements are the bare minimum - no maneuvering ability and no offensive weapons. As Dan has correctly pointed out the idea of attempting to dock with or "land" on a vessel that retains even a fraction of it's maneuvering capability is ludicrous. I'm not even going to touch on the idea of ramming your way aboard.
A boarding party won't be shuffling into airlocks and lining up to mowed down by the defenders either. Even if the use of breaching charges is limited for whatever reason there are plenty of ingress points available to the borders with hull damage being one of the prime candidates.
Regards,
Bill
CosmicGamer
SOC-14 1K
Remember, you not only have to repair the damage to the ship you capture, but the damage to your ship too.
There are other expenses like fuel, life support, blah blah blah.
What % of piracy is successful? Some manage to get away due to lucky weapons fire, successfully repelling boarding, better maneuverability or tactics, rescue ships arriving in time? You still need to pay for expenses and repairs for all the failed attempts, and replace crew you've lost.
There is the whole how does one unload a stolen ship issue too, which I'm sure is covered in multiple threads.
Typically, what do pirates do to crew that resist them? Walk the plank/out the airlock? If so, there is no reason for people to not set the ship to 'self destruct'. "You have 10 minutes to withdraw your boarding party and disengage!"
Yes, a ship can be valuable but so is yours. Take your ship, sell it, and retire. To me, anyone reasonable would not risk their ship, let alone their life unless they are desperate.
In conclusion, I can imagine plenty of safer, cheaper (you don't even need to own a ship), and possibly easier ways to steal a ship than attacking and boarding. But wait, how about that pesky smuggler that the officials need to stop and board...
After all, there is a whole bunch of fun to be had in boarding actions.
There are other expenses like fuel, life support, blah blah blah.
What % of piracy is successful? Some manage to get away due to lucky weapons fire, successfully repelling boarding, better maneuverability or tactics, rescue ships arriving in time? You still need to pay for expenses and repairs for all the failed attempts, and replace crew you've lost.
There is the whole how does one unload a stolen ship issue too, which I'm sure is covered in multiple threads.
Typically, what do pirates do to crew that resist them? Walk the plank/out the airlock? If so, there is no reason for people to not set the ship to 'self destruct'. "You have 10 minutes to withdraw your boarding party and disengage!"
Yes, a ship can be valuable but so is yours. Take your ship, sell it, and retire. To me, anyone reasonable would not risk their ship, let alone their life unless they are desperate.
In conclusion, I can imagine plenty of safer, cheaper (you don't even need to own a ship), and possibly easier ways to steal a ship than attacking and boarding. But wait, how about that pesky smuggler that the officials need to stop and board...
After all, there is a whole bunch of fun to be had in boarding actions.
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far-trader, we have to assume the boarder has faster acceleration.
Once the boarder matches velocity in 3 dimensions with the vessel to be boarded they can be considered to be at rest with regard to each other (the closed system). No matter which variation of direction the target vessel chooses to use its acceleration in, it can only accelerate at a limited amount for the zero relative movement state of the closed system when the boarding ship matched it's velocity. Whichever direction that is, it is still only one direction relative to the pursuing vessel. And the pursuing vessel can accelerate faster and match the target's speed making the effective speed zero faster than the target ship can change speed, as it has higher acceleration. But relative to the pursing vessel they are only moving in one direction. Pitch, yaw etc are factors in situations with inertia which isn't a significant factor in a space pursuit once the relative velocities are zero.
TO actually board once you have matched velocities and made the speed zero you would have close the distance and make the target's relative speed negative, but that is certainly possible if you have higher acceleration. I imagine that a standard technique would be to turn the thrusters in the direction of the boarding ship which would require them to make an oblique approach, whereupon the target would pivot to point the thrusters at the boarding ship again - it would delay things and perhaps catch and inattentive pilot but an alert pilot would have no problems with it.
Once the boarder matches velocity in 3 dimensions with the vessel to be boarded they can be considered to be at rest with regard to each other (the closed system). No matter which variation of direction the target vessel chooses to use its acceleration in, it can only accelerate at a limited amount for the zero relative movement state of the closed system when the boarding ship matched it's velocity. Whichever direction that is, it is still only one direction relative to the pursuing vessel. And the pursuing vessel can accelerate faster and match the target's speed making the effective speed zero faster than the target ship can change speed, as it has higher acceleration. But relative to the pursing vessel they are only moving in one direction. Pitch, yaw etc are factors in situations with inertia which isn't a significant factor in a space pursuit once the relative velocities are zero.
TO actually board once you have matched velocities and made the speed zero you would have close the distance and make the target's relative speed negative, but that is certainly possible if you have higher acceleration. I imagine that a standard technique would be to turn the thrusters in the direction of the boarding ship which would require them to make an oblique approach, whereupon the target would pivot to point the thrusters at the boarding ship again - it would delay things and perhaps catch and inattentive pilot but an alert pilot would have no problems with it.
max: you're ignoring the roll axis.
Matching course and speed is only half the mateup.
But, the ship with the faster drives controls the egagement. a 3G ship can never escape a 4G ship while both have unlimited fuel.
That's not the same as being able to dock and/or board.
Matching course and speed is only half the mateup.
But, the ship with the faster drives controls the egagement. a 3G ship can never escape a 4G ship while both have unlimited fuel.
That's not the same as being able to dock and/or board.
far-trader
SOC-14 10K
Max I think you're confusing the issues. There are two different aspects here, the vector in space, and the orientation of the ship along that vector.
Yes, matching the course vector is simple if the ship is not capable of changing it, but even that is going to be changing abruptly and unpredictably as long as the ship has any maneuver capability. And no matter how much the pursuers maneuver and agility exceed that of the target as long as the target has any maneuver capability it's still a problem to maintain that identical vector and you wont' achieve your zero relative motion closed system. To even match the vector of the pursued ship you need the pursued ship to not make any changes. You can ask them nicely or you can shoot them until they do it nicely or by losing their ability.
But the bigger problem is, even if you could somehow magically effect that matched vector with the pursued ship as long as it has any attitude control you'll never be able to just sidle up to it and latch on or have your boarding party spacewalk over. Never. As long as it can change it's orientation in x, y, and z your ship or people are at serious risk when coming within the length of their hull.
(...ah, aramis beat me to the post button but I was wordier )
Yes, matching the course vector is simple if the ship is not capable of changing it, but even that is going to be changing abruptly and unpredictably as long as the ship has any maneuver capability. And no matter how much the pursuers maneuver and agility exceed that of the target as long as the target has any maneuver capability it's still a problem to maintain that identical vector and you wont' achieve your zero relative motion closed system. To even match the vector of the pursued ship you need the pursued ship to not make any changes. You can ask them nicely or you can shoot them until they do it nicely or by losing their ability.
But the bigger problem is, even if you could somehow magically effect that matched vector with the pursued ship as long as it has any attitude control you'll never be able to just sidle up to it and latch on or have your boarding party spacewalk over. Never. As long as it can change it's orientation in x, y, and z your ship or people are at serious risk when coming within the length of their hull.
(...ah, aramis beat me to the post button
but I was wordier )CosmicGamer
SOC-14 1K
I certainly agree with the BLOODY dangerous! Good post+s.
Also a good point.
-------
Ok, the more I read the more good points I didn't think of. Nice thread.
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The alternative to a boarding action is frequently going to be outright destruction. If the enemy is faster AND more heavily gunned than you, then you have a choice to make --
A) put the ship into a violent, multi-axis tumble which makes grappling and boarding impossible -- in which case you can't maneuver or use weapons -- or keep jinking and jiving annoyingly. In either case, the enemy destroys your ship out of principle;
B) set the ship to self-destruct, in which case you certainly die;
C) surrender abjectly and hope for the best;
D) try to negotiate with the attackers; i.e., "you can have the cargo without a fight if you let us and the ship go afterward; otherwise we self-destruct;"
E) let the enemy board and hope that you can fight him on more equal terms in the corridors.
None of those are good choices, but D and E have some major advantages over A, B, and C -- most notably that they give you at least a chance to survive.
In a clash between military vessels, I can't see a boarding action happening unless a) one ship can no longer maneuver, or b) one ship's captain decides that he can't win a gunnery battle but still has a shot if he lets the enemy aboard, defeats the boarders, and then counter-boards the enemy vessel.
A final possibility is that, in the semi-feudal world of Traveller, the officer aristocracy maintain some code of behavior which holds that launching or accepting a boarding action are the only honorable responses to certain situations. Self-annihilation (along with your entire crew) isn't an option, and only a coward jinks the ship around like a little girl to avoid the inevitable.
Steve
A) put the ship into a violent, multi-axis tumble which makes grappling and boarding impossible -- in which case you can't maneuver or use weapons -- or keep jinking and jiving annoyingly. In either case, the enemy destroys your ship out of principle;
B) set the ship to self-destruct, in which case you certainly die;
C) surrender abjectly and hope for the best;
D) try to negotiate with the attackers; i.e., "you can have the cargo without a fight if you let us and the ship go afterward; otherwise we self-destruct;"
E) let the enemy board and hope that you can fight him on more equal terms in the corridors.
None of those are good choices, but D and E have some major advantages over A, B, and C -- most notably that they give you at least a chance to survive.
In a clash between military vessels, I can't see a boarding action happening unless a) one ship can no longer maneuver, or b) one ship's captain decides that he can't win a gunnery battle but still has a shot if he lets the enemy aboard, defeats the boarders, and then counter-boards the enemy vessel.
A final possibility is that, in the semi-feudal world of Traveller, the officer aristocracy maintain some code of behavior which holds that launching or accepting a boarding action are the only honorable responses to certain situations. Self-annihilation (along with your entire crew) isn't an option, and only a coward jinks the ship around like a little girl to avoid the inevitable.
Steve
Strangelove
SOC-6
Ok try this on....
The boarding party would launch a missile that contains a warhead that resembles a kids toy, the "jack", except the spikes are each a long cylindrical thermal welding rod powered by an on-board superconducting battery. As the target ship thrashes around the mine simply needs one of the dozen or so "spikes" to make contact and it would ignite and attempt to weld itself to the hull. If the impact broke off a couple of the spike arms the missile would be tumbling even faster near the hull and likely cause another arm to make contact.
Once the unit has secured itself to the hull the spherical center of the warhead body would extend a thruster arm with a 3 axis reaction jet. Inside the warhead body is a small reaction mass tank and a computer controlled gyroscope inside a G-resistant container like the infamous "black boxes" of today's airliners. The job of this parasite like warhead is to counter the thrusts from the target ship it picks up with its gyroscope by firing its own thruster. This will provide a counter to their "thrashing" for a short time.
Now there is a limited amount of reaction mass on one of these warheads so the boarding shuttle would need to be close behind ready to intercept and lock on.
Now maybe you'd have several of these warheads on a single missile or perhaps you'd need to fire several missiles to get a small swarm of these things attached. The "drama" would be the boarding shuttle having a short 20-30 second window to get a good lock onto the hull of the target ship before it can outlast the reaction mass on the parasites.
The game aspects I'd think you'd need to balance out for good playability would be:
How many parasites?
How long is their reaction mass endurance?
How strong is the thrust of one?
How big (i.e. multiple warheads or multiple missiles)
The boarding party would launch a missile that contains a warhead that resembles a kids toy, the "jack", except the spikes are each a long cylindrical thermal welding rod powered by an on-board superconducting battery. As the target ship thrashes around the mine simply needs one of the dozen or so "spikes" to make contact and it would ignite and attempt to weld itself to the hull. If the impact broke off a couple of the spike arms the missile would be tumbling even faster near the hull and likely cause another arm to make contact.
Once the unit has secured itself to the hull the spherical center of the warhead body would extend a thruster arm with a 3 axis reaction jet. Inside the warhead body is a small reaction mass tank and a computer controlled gyroscope inside a G-resistant container like the infamous "black boxes" of today's airliners. The job of this parasite like warhead is to counter the thrusts from the target ship it picks up with its gyroscope by firing its own thruster. This will provide a counter to their "thrashing" for a short time.
Now there is a limited amount of reaction mass on one of these warheads so the boarding shuttle would need to be close behind ready to intercept and lock on.
Now maybe you'd have several of these warheads on a single missile or perhaps you'd need to fire several missiles to get a small swarm of these things attached. The "drama" would be the boarding shuttle having a short 20-30 second window to get a good lock onto the hull of the target ship before it can outlast the reaction mass on the parasites.
The game aspects I'd think you'd need to balance out for good playability would be:
How many parasites?
How long is their reaction mass endurance?
How strong is the thrust of one?
How big (i.e. multiple warheads or multiple missiles)
far-trader
SOC-14 10K
Interesting idea, bears some consideration.
On first glance the amount of thrust you'd need would depend on where your missile hits. While the ship attitude control is based around it's center of momentum you won't have that luxury with the parasite(s). Which is another issue, multiples would need to communicate and calculate combined effects, a bit of a wrinkle. I think you'd need to go with one, and a big one, the bigger the ship the bigger the parasite. I don't think it'd be impossible, but probably impractical, for most purposes. It might have to be pretty big to counter a ship's attitude thrusters. And to counter the maneuver drive, well you need the same thrust or more so that's right out for all practical purposes. So you still need to knock out the maneuver drive at least before it'll be any help I think. As long as I already have a tumble I think I can keep it spinning unpredictably just by giving random thrusts with the maneuver drive even if you're countering the minor attitude adjustments. And of course those minor attitude adjustments have proabably added up some too so you not only need to continue to counter the current pitch, yaw, and roll I'm throwing but the accumulated effects as well.
On second blush, not very practical.
But it'd be a great tool for S&R having to deal with deadman tumblers on a regular basis. Where they don't have to fight a constantly reacting sophont intent on not being held still. And of course said S&R locker is where the more nefarious would find one that might, just might, come in handy in a similar scenario.
Heck even smaller "home-built" ones would be handy for roping tumbling cargo containers that a merchie tosses out to shake off the pirates. Built on a normal missile replacing the warhead with the spikes or a sticky of some sort.
Good idea for some uses, thanks for sharing
On first glance the amount of thrust you'd need would depend on where your missile hits. While the ship attitude control is based around it's center of momentum you won't have that luxury with the parasite(s). Which is another issue, multiples would need to communicate and calculate combined effects, a bit of a wrinkle. I think you'd need to go with one, and a big one, the bigger the ship the bigger the parasite. I don't think it'd be impossible, but probably impractical, for most purposes. It might have to be pretty big to counter a ship's attitude thrusters. And to counter the maneuver drive, well you need the same thrust or more so that's right out for all practical purposes. So you still need to knock out the maneuver drive at least before it'll be any help I think. As long as I already have a tumble I think I can keep it spinning unpredictably just by giving random thrusts with the maneuver drive even if you're countering the minor attitude adjustments. And of course those minor attitude adjustments have proabably added up some too so you not only need to continue to counter the current pitch, yaw, and roll I'm throwing but the accumulated effects as well.
On second blush, not very practical.
But it'd be a great tool for S&R having to deal with deadman tumblers on a regular basis. Where they don't have to fight a constantly reacting sophont intent on not being held still. And of course said S&R locker is where the more nefarious would find one that might, just might, come in handy in a similar scenario.
Heck even smaller "home-built" ones would be handy for roping tumbling cargo containers that a merchie tosses out to shake off the pirates. Built on a normal missile replacing the warhead with the spikes or a sticky of some sort.
Good idea for some uses, thanks for sharing
Strangelove
SOC-6
It is only a KKM if you have a high closure speed but in this example the ship is disabled and only able to spin on its three rotation axes so there is not a requirement that the missile be your typical high G model. You can get within range with your primary vessel so there would be minimal closure speed. The problem, as I understood it to be explained, is that the target can't run just spin and threaten you with collision. With this model you keep the primary boarding ship a safe distance and use the parasites to actually encourage collision with them.
The parasites could be quite large and likely would use chemical thrusters instead of cold-gas, like the target, giving them a large thrust for a short duration. The parasite could be 10tons and slow, as long as you can get close and throw it into the path of the thrashing target a collision is nearly assured. Plus the length of the boom arm extension from the warhead will give you a mechanical torque arm to help multiply the effective thrust relative to the target CoM.
An alternative could be warheads with a dense flywheel in them. Once the warhead attaches itself to the target vessel the flywheel spins up to very high speed and that will attempt to stabilize the spinning vessel. The vessel masses more and spins slower but a 1 ton flywheel disc at several tens of thousands of rpms will give it far more angular momentum than the ship can muster causing it to become the primary spin control.
Or perhaps just get small, very accurate seeker warheads and have them knock out the thrusters directly. If they are thrusting enough to spin the target vessel they should make *fairly* visible targets.
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Not very practical, and fairly unrealistic, Strangelove.
If it's massive enough to be able to impart significant ∆V on a scout ship massing at least 1000 tons, and the scout has enough rotation to make boarding hard, it's going to smak any protuberances with significant impact force.
The ship's own rotation is part of the damage potential.
If it's massive enough to be able to impart significant ∆V on a scout ship massing at least 1000 tons, and the scout has enough rotation to make boarding hard, it's going to smak any protuberances with significant impact force.
The ship's own rotation is part of the damage potential.
Strangelove
SOC-6
An object cannot spin about multiple axes with all of them having high rotation rates due to the right hand rule of angular momentum. It simply cannot be done. Hence at least one axis will present itself as a much easier target rendering the whole thread sort of moot. I could dig out the formulas from SMAD or Fund. of Astrodynamics regarding satellite spin and perturbations but it would be overkill.
If you are assuming the ship is rotating with some significant velocity then it is safe to say that the 1000t ship will become its own gyroscope about a single axis. If it tries to thrust in another direction it will slow down its own original rotation from the summation of two of the vectors. Imagine a top spinning, the x and y axes are presenting a spinning face but the axis of spin is nearly stationary. To try and induce a rotation along the nearly stationary axis means the right hand rule would cause the other rotations to slow.
My assumption was a ship inducing a slow oscillating tumble that switched from one axis to another. The slow rotation provides the basis for adjusting the thrust.
So it either is spinning too fast to apply adjustment thrust, either from itself or a "warhead", which causes it to be its own gyroscope and gives you axis of approach or it is tumbling and is vulnerable to adjustment.
If you are assuming the ship is rotating with some significant velocity then it is safe to say that the 1000t ship will become its own gyroscope about a single axis. If it tries to thrust in another direction it will slow down its own original rotation from the summation of two of the vectors. Imagine a top spinning, the x and y axes are presenting a spinning face but the axis of spin is nearly stationary. To try and induce a rotation along the nearly stationary axis means the right hand rule would cause the other rotations to slow.
My assumption was a ship inducing a slow oscillating tumble that switched from one axis to another. The slow rotation provides the basis for adjusting the thrust.
So it either is spinning too fast to apply adjustment thrust, either from itself or a "warhead", which causes it to be its own gyroscope and gives you axis of approach or it is tumbling and is vulnerable to adjustment.
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far-trader
SOC-14 10K
Some of this will depend on the method of attitude adjustment used as strangelove notes.
There's the simple fueled jet method, with small multiple vector jets placed at points on the hull. Easy enough to target but ship weapons are going to really do more damage than you want
There's the part of the maneuver thruster plate model, where main (full thrust is along the primary axis but it is also directional with serious drop-off the further off the main axis you go and minimal reverse thrust without spinning the ship.
And there's the model where attitude adjustment is handled by a very dense very high velocity gyroscope mounted in the center of the ship which is braked against by the ship using gravity modules to impart spin.
In the first there is no specific damage roll to target it so it should be part of the maneuver drive imo. Kill the M drive and you also have no attitude adjustment.
In the second it is by definition the M drive, so again kill the M drive and you lose attitude adjustment too.
In the third it's separate from the M drive but reliant on the power plant so it could be lumped in with that for damage, no power (or fuel) and no attitude adjustment (and of course losing power/fuel also means no M drive).
Depending on the method used (and some ships may have more than one of the above) will decided what might work to counter it.
Good thoughts on the gyroscopic effect Strangelove, I'd forgotten that.
There's the simple fueled jet method, with small multiple vector jets placed at points on the hull. Easy enough to target but ship weapons are going to really do more damage than you want
There's the part of the maneuver thruster plate model, where main (full thrust is along the primary axis but it is also directional with serious drop-off the further off the main axis you go and minimal reverse thrust without spinning the ship.
And there's the model where attitude adjustment is handled by a very dense very high velocity gyroscope mounted in the center of the ship which is braked against by the ship using gravity modules to impart spin.
In the first there is no specific damage roll to target it so it should be part of the maneuver drive imo. Kill the M drive and you also have no attitude adjustment.
In the second it is by definition the M drive, so again kill the M drive and you lose attitude adjustment too.
In the third it's separate from the M drive but reliant on the power plant so it could be lumped in with that for damage, no power (or fuel) and no attitude adjustment (and of course losing power/fuel also means no M drive).
Depending on the method used (and some ships may have more than one of the above) will decided what might work to counter it.
Good thoughts on the gyroscopic effect Strangelove, I'd forgotten that.
CosmicGamer
SOC-14 1K
Regarding the reaction missiles to counter thrust: It was interesting and I was thinking about the logistics and came up with a possible snag. I'm no physics guru so others will have to analyze this: The engines/thrust produced by the ship is anchored to the 'frame' of the ship. The equal and opposite thrust you are trying to create comes from missiles that self weld to the hull. Wouldn't the stress possibly rip off a part of the hull?
CosmicGamer
SOC-14 1K
Certainly? I believe the concept here is to possibly destroy the attacker too unless they withdraw to a safe distance. Once the attacker withdraws, you can cancel the self destruct.
"Dang it, I forgot the codes to cancel the self destruct. All hands abandon ship!"
Strangelove
SOC-6
Well certainly it would greatly depend on the orientation of the welded contact area.
If the spike welded itself perpendicular to the surface of the ship (think _|_ ) then your weld joint would be subjected to a combined torsion load at the end of a moment arm. Similar to using a longer wrench to loosen or tighten a stubborn bolt, yes the longer arm gives you more leverage but it is more likely to tear apart the joint.
If the spike welded itself parallel (think = or || ) to the ships surface then you are going to have long lines of weld rather than simply the circumference of the rod as above. This would prove a *vastly* stronger joint since you'd have so much more contact surface to resist the combined twisting of the thruster.
It really boils down to shear stress of the weld relative to the shear stress in the spike arm. In short you'd snap off the spike arm before you tore a piece out of the hull unless the spike arm was made of something far stronger than the ships hull which is unlikely as you need it to effectively be a welding rod in addition to a support strut. For the weld on parasite to work the hull and the spikes need to be weldable using plasma or electric arc. If the hull is steel and the spikes are titanium, for example, you'd be S.O.L. because you couldn't get them to weld.
As to the strength of a weld, that subject has a legion of info about it. Suffice it to say two 12" beads of 3/4" weld along two A-36 Carbon Steel (the common stuff) plates say 3/4" x 8" in cross-section (per plate) will hold a tension load of 80,000 pounds easily. The weak point being the weld obviously. 6 square inches of steel plate would rate a 180,000 pound load in tension assuming a 30,000 pound/sq inch safe stress. This means the weld would break before you'd cause the plates to tear apart in a "pure tension" situation, think a rope in tug-o-war.
Of course this could all be averted if the starship hull is assumed to be made of something like ceramic or covered in 6" of ablative rubber like a submarine. Two part adhesives exist today that will weld sheetmetal quite well, so *in theory* you might in the future be able to get your spikes to have an adhesive on them that won't sublimate in a vacuum that will bond ceramics or rubbers. I'm not very familiar with adhesives in a vacuum.
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