Multiple docking ports?

[Strainborm]

So I am making a ginormous interplanetary ship, and at one point even single 2.5m docking port just doesn't cut it. Is there a way to dock using 2, 3, or 4 docking ports? (and not just for cosmetics, like actually connected docking parts) I've heard that there's a plugin that help you do that, but I cannot find it anywhere Any help is greatly appreciated

[moogoob]

I've seen it done, but it's very, very tricky. If you're slightly off, it can become impossible. Are there mods that have bigger docking ports maybe?

[Starman4308]

Behold!

Just make sure your docking ports line up in the VAB, and use that tool to dock with the correct orientation.

[Frank_G]

Take a look at my mission to Jool (link in the signature). It is not only possible to use multiple docking ports on a single ship link, it also delivers rock solid connections. And besides that... Orbital assembly is one of the most fun things to do in KSP. Good luck on your project

[Strainborm]

Behold!

Just make sure your docking ports line up in the VAB, and use that tool to dock with the correct orientation.

I already use DPAI It is a very useful plugin indeed, but not quite what I need.

Edited November 6, 2014 by Strainborm

[Oafman]

Simultaneously docking multiple ports is really hard to do.

As an alternative, KW Rocketry includes 3.75m ports. They're huge and heavy, but if your ship is big enough they might be a better option

[Frank_G]

When you plan your ship precisely, docking it together isnt so hard in my opinion. Plan the parts with an eye on center of mass, add some RCS (maybe even detachable RCS) and docking is a cakewalk... However you will need patience. You cant slam em together like with single ports.

[edit] a heavy (meaning lots of mass) construction vehicle to push things in place is also a big help, when it comes to dock long or assymetric parts. The construction vehicle pulls the combined mass towards its own, allowing very acurate controlled maneuvers.

Edited November 6, 2014 by Frank_G

[Tokay Gris]

It is not only possible to use multiple docking ports on a single ship link, it also delivers rock solid connections.

Yes and no.

You can dock multiple ports. But only one will be a "real" connection".

I once did a space station consisting of six parts to form a hexagonal structure. It did dock all right, but because there were quite a few connections, the difference in the end was noticeable.

It worked out fine, until time warp was used. The last two ports (each of the six parts had four) slid away from each other in time warp and had to realign again coming out of time warp.

That said, if you use - say - three ports in a triangle shape and succeed in docking them, you will get a pretty strong connection. But only one will be "really" docked. (All will say "docked" on right click, though).

This becomes important if you dock tanks together. The "real" docked ports will let fuel flow through, but the others will not.

[Lunaran]

Here's a bit more detail on why everyone is saying what they're saying:

When you have a triad of docking ports approaching another triad of docking ports, every frame the game is checking one at a time. They get closer and closer, and when a facing pair are close enough, it starts to apply magnetic force to both of them to help encourage them together. When it finds that a pair of them is close enough to be within a certain tolerance, they're snapped together and the vessels are joined.

The game then stops caring about the other ones in the same way, immediately, during that frame. They're not on separate vessels anymore so clearly you aren't docking them, so why test them?

Docking ports on the same vessel can be joined, in an operation that's a different code path than above. The tolerance for joinder is a lot more strict - it has to be pretty much exact. The reason for this is that this code path only really exists for two docking ports that have been already placed face-to-face in the VAB, to catch them at vessel initialization and make sure that their state is changed to "docked" and not "just welded together like any old fuel tanks."

This means that when you bring your fancy triple-clampotrons together, in order to get all three to lock together and form a physical joint, you have to be VAB-snap-precise. This takes many many tries, and 19 times out of 20 you're gonna get one docked pair and two that are noticeably sliiiightly cockeyed. Once that first pair is joined and the vessels dock officially, no 'roll' happens around that axis any longer, so you are stuck with whatever slight misalignment you still had at the time on the other two.

It's still possible, though. One good tip is to point your ships normal/antinormal (north/south) so that your docking adapters are meeting up and down. This will eliminate the need to always be gently compensating for (ie, fighting) the libration effect of the rotating reference frame. But it still takes forever.

[Laie]

You can dock multiple ports. But only one will be a "real" connection".

Hum hom. This only really matters for fuel flow rules. In any other respect, the connection is as real (strong, durable) as any other.

The game then stops caring about the other ones in the same way, immediately, during that frame. They're not on separate vessels anymore so clearly you aren't docking them, so why test them?

I'm pretty sure that this is not true. I'm habitually using multiple connections without problems. Using Smart A.S.S. for alignment, I usually get them all connected on the first attempt.

• I'm certain that not all of my connections always come together in a single physics tick, yet they do come together.
  
• when I was concerned about fuel flow, I made one port stick out a little (just a little, half an inch or so) as to make sure that this would be the connection that joins first. That means, I deliberately made it so that the ports would not join in the same instant. This worked very well, and usually (but not always) in the order I had in mind.
  
• I once had a ship with stuck docking ports (wouldn't undock) and had to edit the savefile in order to get them unstuck. This involved changing their state from "docked" to "waiting for connection" or something along these lines. All ports in question were still on the same vessel, yet they joined nicely after the hack.
  
• when the connection that was fuel-conductive was not to my liking, I undocked all other connections, quicksave/quickload, and they all came together again. (Though I suspect that this was the reason for the stuck docking ports that bugged me later on).
  
• In every case where some connections did not join, they were visibly mis-aligned.
  

[DerekL1963]

I'd try installing Kerbal Joint Reinforcement before tackling complex multi-port schemes.

[psyper]

I have a fuel transporter which has 4 radial orange tanks which connect to 4 other radial orange tanks (the transporter is brought up to orbit in two separate sections and joined together in orbit). When creating them I used the same basic structure for both ships so they are basically identical (created the first one put a probe core and engines on it - saved it and then remove the engines and probe core and saved that as the 2nd part). I use the docking port alignment mod which was suggested earlier. brought one part to a couple of meters away the from the other and used the alignment mod to make sure that not only do they line up but are also orientated to 0.01 of a degree from each other. I switched to each port selecting control from here and then targeting that ports partner to ensure all of them matched the same. Then coasted them together at about 0.14 m/s. All 8 connections are connected together - each pair shows one docking port with the disconnect option so they are showing as docked. I can turn the craft pretty harshly and can kick the engines in and it doesn't show any wobble and there are no gaps forming on the docks as far as I can tell so to me they are all real connections.

I've done this a few times now and at first its really hard to get them all to line up exactly right but a few tries the first time and you get the hang of it after that.

[Kryxal]

I was going to suggest quantum struts, assuming there's a bulge or branching on one side or the other...