Docking Ports.

[Flixxbeatz]

Since the conception of dock ports, it has become my habit to put 2/3/4 (never 1) 1m docking ports instead of 2m ones to join 2m-diameter segments if there is only one connection due to their inherent instability to hold segments especially when turning massive ships (interplanetary stuffs) and because I want the ship to dock in a certain orientation (even the slightest rotation will make me undock the ship, rotate a bit, and dock it again in case of 2m dock ports).

That's why I don't do side-facing ports like this (especially it the things docked on both sides are of uneven weight - it throws the ship off-balance) since the acceleration tends to leave the part behind (a.k.a "bend backwards").

Apparently, in case of this one (note the dock ports on that thing):

Wobbliness was still experienced even when using multiple port mechanism when I've turned it to a certain heading. I've right clicked every node in the assembly, and all gave me the "undock node" option - meaning they're all docked so there's no way it could wobble the ship.

Am I doing something wrong? Or the game really just works like this?

How to minimize wobble without using any plugin?

[CaptApollo10]

Try turning off SAS on the docked parts.

[Taki117]

The issue with multi-docking is that while all ports will SAY they are docked, only one port is the main docked Node. I suggest getting KAS to strut your ships.

[Jouni]

The problem is probably with the design itself. The ship consists of two heavy components connected by a long narrow region. Such designs will almost inevitably wobble, even if you replace the docking ports with structural connections.

To make modular ships more stable, place as much mass as possible within a single rigid module, and make sure that center of mass of the entire ship is within that module. If you need to dock other heavy modules, place them as close to the center of mass as possible.

[vitekc45c]

Try building exoskeleton around the ship using girders (and struts) and jr. docking ports, something that would connect all modules together and stop the noodlefication effect. Something like this.