docking ports "unbreakable"?

[Dewm]

Title pretty much sums it up. I'm thinking of designing some sort of a space tug, but I'm wondering how much they can pull? thanks!

Side note: can you set up certain engines on and off via the action groups?

[JazzXP]

Title pretty much sums it up. I'm thinking of designing some sort of a space tug, but I'm wondering how much they can pull? thanks!

Not unbreakable, but can take quite a load. Should be fine in space

Side note: can you set up certain engines on and off via the action groups?

Yep, it's very handy so that you can have forwards and backward engines on your tugs :-)

[samstarman5]

While I can say the Jr and standard ports alone aren't suited for spacecraft assembly in orbit, they do have a fair amount of strength. But people can tell you they are strong, they aren't up to snuff, they can do so-and-so amounts of pull before breaking. In the end, it is always best to test it yourself. Go for the most extremes and work your way down. What you will discover you will have ingrained into your own experience and remember better than what somebody told you in their own wordage here.

That is what KSP is about, discovering these things yourself. Never expect the tough things to be handed to you. That isn't how it works.

Side note response: Play with the action groups yourself. They are actually very versatile, and while I haven't applied them to engines myself, my first hunch is going to be: yes.

[HeadHunter67]

Indeed, it's great for tug designs. Put a set of engines that thrust prograde and assign them to Custom1, for instance. Then put a set that thrusts retrograde and assign it to Custom2. Also set the other engines to deactivate when activating the desired set - so pressing one activates forward thrust and deactivates retros, and vice versa.

[regex]

I use the standards regularly for putting together Duna tugs; they're plenty for relatively balanced payloads under 40 tons.

[Vanamonde]

Docking ports can crush under a large load, but are surprisingly strong under tension and torsion. This is the result of a botched aerobrake attempt. Nothing broke off of the ship until it hit the "water," or whatever that stuff on Eve is.

[Kerba Fett]

Indeed, it's great for tug designs. Put a set of engines that thrust prograde and assign them to Custom1, for instance. Then put a set that thrusts retrograde and assign it to Custom2. Also set the other engines to deactivate when activating the desired set - so pressing one activates forward thrust and deactivates retros, and vice versa.

While that's a good idea, you should also add a couple of lights to use as indicators for which direction is active. You add them to the same action groups that switch the engines. Nothing worse than starting a burn and finding out the wrong set of engines is active.

You might also want to add a fin, light, RTG or other marker for the top of the ship if it's not obvious from your design. That way you can orient to the top of the screen for more intuitive RCS when docking. You can also use the chase view to line up the top of the screen to the top of the ship, but it moves with the ship and you might want a more static camera when docking.

[SkyRender]

Be aware if you plan to use Clamp-o-Tron Sr. ports where you might normally use a decoupler: they have noticeably lower impact tolerance than other Clamp-o-Trons, and far lower than decouplers. A C-o-T Sr. will fail with its connecting link if it experiences more than about 2 Gs during launch for most typical uses (and less if you have a lot of mass on either side of the impact or a high amount of wobble near the port). This leads to slower lifts and potentially more wasted fuel getting into orbit, depending on your launch technique.

Technically, the load you can lug with a Clamp-o-Tron is effectively infinite in space proper since the primary factor for linkage failure is G-force; you can easily keep all G-forces in space well below the limit and not run the risk of crashing into the ground like you do in suborbital conditions.

Edited August 23, 2013 by SkyRender

[Crown]

[..]but I'm wondering how much they can pull? thanks!

The KSP Wiki tells something about the strength.

Side note: can you set up certain engines on and off via the action groups?

Yes, it is possible to turn single engines off and on but only when they are placed separately. If you have four engines attached to a Stack Quad-Coupler with 4x symmetry, only all engines can be switched. If you placed them with no symmetry, any single engines can be "action-grouped" individually.

There's a little bug in the action group behaviour when you grab a part which was placed with symmetry and re-place it. Only the part you had in your hand remembers that it was in an action group.

[KerbMav]

Can docking ports be made unbreakable by modding? Reducing or negating flexibility between two ports?

And then not name them docking ports, but make them self-bolting-and-welding-construction-rings, cannot be "decoupled" because they weld together (maybe even merge into one single part - although I do not think that is possible?) but would be perfect for station/ship building.

[HeadHunter67]

While that's a good idea, you should also add a couple of lights to use as indicators for which direction is active. You add them to the same action groups that switch the engines.

That's good advice! Thanks for the tip.

You can also use the chase view to line up the top of the screen to the top of the ship, but it moves with the ship and you might want a more static camera when docking.

No, I much prefer chase cam when docking. That way, RCS controls are always properly aligned to my view. If I tap J, the craft will move left on my screen. A lot of people who have trouble docking are doing so because they struggle with trying to reorient the ship's controls to its position ("Since I'm turned this way, does I move me down, or left? Or forward?").