Clutch fan installation question

I've done this 3 times in a 2 day span.
I have 1" 5/16" bolts with captive washers to use. They are OEM Chrysler/Mopar from one of the many cars that I have parted out over the years. No lock washers, no Locktite, just adequate torque to tighten and they stay that way. I use a long 1/2" combination box end wrench after fingering them to start the threads. There are a series of 1/4 turn efforts on each bolt so it takes awhile. This is with a 7 blade fan too. Those have a slightly irregular fan spacing where there are a few sections where the fan blades are slightly further apart. I took off a 6 blade fan that was evenly spaced. That made access to the fan clutch bolts difficult.

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It helps to thread one bolt in 2-3 turns, then slip the fan and clutch onto it, then thread the one across from it to hold it in place.
What is a "captive" washer?