Docking port strength

[rfdesigner]

I'm building a fuel depot to land on minmus, so I've included a couple of the biggest fuel tanks, empty with docking ports and wanted to attach them to the body of the lander, so it makes it wider and more stable...    just very big.  To get it out of the atmosphere it's all stacked inline and then I'm docking it in LKO.  I've built things with docking ports before and been able to rotate them after docking, but for some reason the docking ports are refusing to turn and just breaking off.

The S3-7200 fuel tanks are empty at this point, so the mass isn't stupid, about 5 tons for the smaller section being docked.

Any ideas as to why this is happening?

[Vanamonde]

They are breaking under acceleration? Can you share a picture of your craft when it happens? 

[king of nowhere]

the mass definitely should not be enough to break the docking ports. they may break on the ground under weight, but in space, for rotation, they should not.

anyway, try autostrutting. it's the common solution to all stability problems.

[rfdesigner]

not breaking under acceleration..   in orbit..  docked, zero-g..  try and rotate the part with all engines and thrusters disabled and it won't move.. then the ports snap off where they're attached.. so I end up with my carft, the tank floating on its own, and a pair of docking ports floating away.

KSP1 with EVE, Scatterer, parallax, planetshine.

I'll have a look at autostrutting, thanks

Was about to add images..   but I see I need to find a web hosting service..   that'll take time.

 

Edited June 8, 2024 by rfdesigner

[Vanamonde]

Imgur.com is an easy to use and free picture hosting site. 

[Biggen]

https://postimages.org/
 

That site is all you need to post images. Easy as pie. No registration needed. 

[rfdesigner]

solved

The problem was a defective nut.  The one between the keyboard and the chair.

thanks to postimages I can now show the pretty pictures...   pre turning

post turning:

Then I realised my problem: there's a "rotation locked" button staring me in the face...  doh!..    unlock and all is good.

anyway..  I've now managed to land this on minmus (ran out of fuel with about 5meters to go)..  refuel and prove I can take off into orbit (see below)..  but I forgot to put an antenna on, so need to go back & do that..   this was in a sandbox "simulation", which will allow me to use my autotakeoff & hoverslam scripts (I ought to just load the programs at launch, but they get updated occasionally)...  at least I've proved the concept.

thanks for the help..   I've learnt new things!

[Vanamonde]

Glad you got past it.

[nrum7366]

It could be that the ports are not on a attachment node??? 

In anycase bring spare docking ports and get your Kerbal out on EVA to do repair.