Multi-port Docking Problem

[Fac3Value]

Hey Guys,

I'm trying to launch a ship that consists of two parts docked together, and am using tri-coupler docking to do so (where you put three docking ports on a tri-coupler for increased stability) to keep the ship from wobbling as much. However, there is a reoccurring problem; it seems like I can't attach all three docking ports to both tri-couplers in the VAB. I tried to build it first by putting three ports on a tri-coupler (facing upwards), rotating and placing three ports on top of those, and placing the second tri-coupler to that. It seemed to stay together during flight, but when I got orbit and tried to undock the two parts, tow of the three docking ports on one of the top tri-coupler fell off and floated away.

It looks like you have to attach docking ports DIRECTLY to tri-couplers for them to stay on, so what I did by just placing the tri-coupler on top of three upside-down ports didn't work. I've been fiddling around with this for quite some time and have only managed to attach two ports directly to the top tri-coupler. Does anybody have a way to actually get all three ports to stay on the damn thing?

The docking port structure I'm trying to accomplish:

This would be an easy fix, but some strange stuff happens to the attach nodes when I try to move it:

[OdinYggd]

That happens because the current ship structure is a tree shape that does not allow loops.

One way to counteract it is make sure all of your docking ports are anchored securely to the parts they attach to, although only one of them can be actually attached in the VAB the others should grab fairly quickly once it gets out to the launch pad.

[paleorob]

Use stack separators instead of the lower ports? Would that solve the issue? or do you need the lower stage to dock as well?

[NeoMorph]

Use a single docking port and add a ring of Quantum Struts. That's what I do to get around the floppy connections problem. I could never get the triple (or double) docking ports to dock at the same time. Not had ANY problems since using the single port plus quantum struts and it is stable as a rock.

[HoY]

I did a tutorial for exactly what your trying to do. The thread got eaten in the crash but here's the video.

Edited May 6, 2013 by HoY

[Tristavius]

Would strongly recommend the SubAssembly Loader mod... even if you're a mod purist like me it should be a must-have for ship design. What you can do is save one of the tri-couplers and it's properly attached docking ports and recall it many times as necessary. In this case by loading 2 in and connecting them they'd both have all their ports properly attached. Haven't found another way round this issue sadly, short of launching the two parts separately. Of course if you don't need to keep one of the sections and it will be discarded, don't use the ports at all, just have the other ports on the other section lock directly onto a tri-coupler on the other.

[HoY]

Trist: watch the video it shows first the wrong way, then the correct way to connect them

[Tristavius]

Ah sorry, missed your post... Will watch when I get home, would be interested to see the non-mod method