Jimmie, that Nissan thing is a bad example as at least I can`t see where that other line goes to for sure and who knows if the writer is using correct terminology.
The word "surge" gets confusing because a rad surge tank is truly a surge tank but vented where a hydralic loop (not a circle in the tubing but a separate circuit as I described)cannot be vented or the system would be rendered useless.
Just for the record I did study hydralics a loooong time ago but never got so involved as to do calculations on friction loss in a pipe. Common sence tells me there is not enough friction in a looped clutch line to make any noticable difference. I don`t believe there is any way to prevent hammering in a solid circuit without using an air chamber,spring loaded piston or diaphram or expandable (like a baloon) piping. All friction would do is produce heat and slow the action. I am sure we can all agree that fluid will not compress, without compression there is no absorbtion of hammering.
Can you show us any kind of assembly line, auto,, heavey equipment hydralic circuits that use a circle in a piece of pipe that dampens. Phsyco babble about calculations don`t do it for this dummy.
I respecfully suggest that somewhere sometime you got the term "hydralic loop" confused with a circle in a piece of pipe as apposed to a separate circuit loop. Some loops are tied in to just a single line and others at both ends of the circuit, both the pressure side and the business side to absorb harmful hammering. They could have several circuits all going to a main absorbtion unit.
Possibly you could give those of us driven by curiosity a link to an appropriate engineering forum where you could ask the question and we could get some factual answers and examples.

George