With the thread already three pages long
(actually, now five
, while I repeatedly tried to preview this message and getting server errors, then copying the text and starting again), I'm inserting by twopennorth after only reading the first page, to make sure I'm PTW.
I've not had any personal experience with plate armour, but I've made (and worn, obviously) my own chainmaille, as I'm sure I've previously mentioned on these 'ere forum-type-things. Slightly anachronistic (but not silver-painted plastic rings[1]) and not
professionally finished (closed rings having their ends 'riveted' together... I just relied on the material strength to keep them bent into shape).
The stuff worn by shark-divers (and similar stuff worn as gloves by butchers and the like) is finer and probably uses a more suitable alloy finished in a more suitable manner. (Wouldn't be surprised if it weren't 8-1 or even 10-1 linkage, rather than the pretty open 4-1 or (as far as I've generally gone, except for jewellery-type pieces) 6-1 packing.) I don't know how well an anti-shark suit would do, if wormholed back into days of yore, but I reckon it'd at least out-perform on a weight-by-weight basis, despite the added density of linking that I presume it has.
In preparing for a time-slip, assuming that our Kentucky Yankee knew in
advance that he/she was going to end up in King Arthur's Court, then I don't suppose that a standard set of police riot-gear would go amiss at all. I'm not sure if ballistic armour would be a good investment (I don't know how it stands up to rains of arrows, bodkin-heads, etc), but the anti-stab vests (and more, ideally) might be useful, and the plexiglass/whatever shield would be among the an unexpected items (the transparent visor also, even if the rest of the helmet doesn't look
too amiss, or can be surmounted by superficial decorations to fit into the period) that could either help save day
or I suppose, mark our displaced person down as a target to be bested...
However, the one thing I'd wish to make sure I had (especially if I was in danger of facing archers, and regardless of the rest of the protection I'd end up in) is silk under-armour. Or, in lieu of armour, padded silk jacketing for as much as my body as possible. This is mainly to help prevent the arrows that I
surely wll be hit by (assuming I don't just lie low and/or successfully pretend to be Merlin with all my 'magic knowledge' somehow used with the materials I'll have at hand) from making more of a mess on entry than they might otherwise do, and allow easier extraction if they
do penetrate (and I survive that injury and the warclubs/etc that come along while I'm writhing on the ground in agony).
Knowledge would probably the best armour though. Firstly enough backwoodsmanship to compete with the local time's backwoodsmen (which'd be a hard ask), assuming I didn't instead try to get myself well acquainted with the established protocols and structure of the nobility so that I could cadge room and board off of them. After that, From-the-ground-up stuff like blacksmithery, pottery or another useful trade that involved furnaces and could lead to a few steps along the way to my own little Industrial Revolution. Although it's by far too late to compete directly with the 'locals' who had been smithing all the way from apprentices up to being the quality workmen that ultimately must dot the land... My one exceptional attribute may yet be my age and health (assuming that I don't just look younger than my <cough>ty-<cough> years, to the weather-beaten and healthcare-less inhabitants of the time). And my unexceptional height may (literally) help me stand out from the crowd, for better or ill. (Another reason why I might be able to 'pass' as a noble, and require me to know how to act like one and blend in whilst avoiding the jousts and other combat games that I'm ill-prepared for.)
If nobody's mentioned
arms yet... Not sure. Guns (not something I'm overly familiar with, in daily use) would run out of ammo, tasers would run out of power (also doubt they'd work against a metal-clad warrior). I was coincidentally thinking the other day, however, that my pretty boring
bread knife might be an exceptional piece of bladecraft in times past. (Probably ineffective against armour without the skill to dodge in and get
just the right angle to penetrate some chink in the armour (and the armour that protects
those chinks... And a good chance that it'll get snapped at some point, so less useful than a native rondell dagger, methinks, but perhaps would work as a misericorde to give the mercy blow to someone I'd somehow defeated by other means.)
[1] Although I
did make some test pieces out of green-plastic coated garden-wire. A bit lighter than the volume of each ring would suggest, non-rattling, or at least not with a metallic rattling, and non-reflective, so might have been considered useful for a "Night-assault Knight"...