[vicky_molokh]

I see that External Clamps have ratings in tonnes (equal to hull mass of the ship for normal, 1/3 hull mass for Small). However, I'm not sure that makes sense:

First, I see by RAW a Small clamp is merely limited to grabbing ((Ship SM)-3) sizes of object, while a normal clamp simply has no limit; I don't see the mass indicator.
Second, mass doesn't tell us much, because we don't know the maximum tolerated acceleration, and thus the force with which the clamped object 'pulls back'. Keeping hold of 3-tonne object at 1G is quite easier structurally than doing it at 10G! (Also, having maxMass == myHullMass results in never, ever being able to slowly tug a larger ship.)