[LT] Refluffing Mail and Plate as Plate over Mail?
 

As far as I know, the Mail and Plate armor is a mail with many small plates, like a scale armor with mail backing instead of cloth or leather, and representative of armors from eastern europe and middle east.
Would I break anything if I instead treated the Mail and Plate as the transitional period armor with larger iron plates strapped on mail and then apply the rules for Heavy Plates?

Re: [LT] Refluffing Mail and Plate as Plate over Mail?
 

I gave a quick glance over the low-tech book, and what you're describing matches up more closely with the armor described under segmented plate. Probably the 'coat-of-plates' or even just 'plate' since mail reinforcement was used at joints and other spots. If there's mail under the plate, then it's layered with the associated (non)penalty.

However, the 'heavy plate' rules are pretty loose as to what they're describing. Mostly just stating that chunks o' metal can be made thicker for a price. So, if what you're using has chunks o' metal, and they can be made thicker, then yeah. Actually, re-reading it, the section states that 'all armor with large plates, including segmented and brigandine" can be treated with heavy plates. Mail and plates is such a close cousin, if it passes the sniff test yeah man go nuts make that armor thicc

edit: Oh yeah, and given the wide wide world that makes up different styles of armor mail and plates should consist of 1) mail, and 2) plates, and use the stat line for mail-and-plates.

Re: [LT] Refluffing Mail and Plate as Plate over Mail?
 

I believe the 'coat of plates' refers to the vest being worn here. It seems to be a sort of early brigandine over mail.
However what I had in mind is what's shown here and it is early breastplates, vambraces and poleyns over mail. According to LowTech Load-outs, the official way of doing this is layering light mail armor with medium plate armor, stacking their DR and causing DX penalty.
My idea was to instead use the mail-and-plate armor to avoids DX penalty and use the Heavy Plate rules to make it stronger. They're designed and built to be worn together so it shouldn't be as awkward to move in it as any other random combination. The resulting armor is much heavier than layering mail and plate so it's not particularly munchkiny: Light mail and medium plate gives DR 9 and wieghts 32 lbs, mail-and-plate with DR increased to 9 using the Heavy Plate rule would weight 60 lbs.

Re: [LT] Refluffing Mail and Plate as Plate over Mail?
 

I doubt you would break anything. Whether it's realistic is another question.

Re: [LT] Refluffing Mail and Plate as Plate over Mail?
 

Yes, Mail and plates is the Turkish/Persian type of armour with medium-sized plates linked by mail. A breastplate or pair of plates over a shirt of mail is two separate pieces of armour built of two different materials in GURPS.

If you want to avoid the weight and DX penalty, wear Voiders and Gussets on your Arming Doublet. I don't think LT has stats for them, ones covering the inner elbows and armpits should be 20-30% as heavy and expensive as a Torso + Arms.

Re: [LT] Refluffing Mail and Plate as Plate over Mail?
 

It won't really break anything but it isn't a practical solution. Once the plate gets to a certain thickness in the mail-and-plates construction, it stops flexing/articulating properly. So you get DX penalties anyway.

The best way to address the problem is to use mail gussets/voiders like Sean suggested.

Keep in mind that 14th century plate over mail combinations were primarily intended to be worn by cavalry. The weight burden and movement hindrance isn't so much of a problem when in the saddle.

Re: [LT] Refluffing Mail and Plate as Plate over Mail?
 

LT describes arming garments on pp.101-102. Stats for arming doublets with mail voiders are at the end of p.101. The section also has rules for what happens when you try wearing plate harness without an arming doublet. There are two practical examples of arming doublets in the Loadouts book ("15th-Century German Ritter", pp.39-40, and "16th-Century Italian Condottiere", pp.41-42).

Re: [LT] Refluffing Mail and Plate as Plate over Mail?
 

Not really. Mail-and-plate is like lamellar except that the plates are connected with metal rings instead of lacing. There is no backing. It was a clever way to eliminate a lot of the problems inherent in lamellar.
https://en.wikipedia.org/wiki/Mail_and_plate_armour

What you are thinking of is Roman. It consists of small scales integrated into a mail backing. It is often erroneously called lorica plumata but a more accurate term is lorica hamata squamataque. The Loadouts book (p.23) has stats for it.

Re: [LT] Refluffing Mail and Plate as Plate over Mail?
 

Re: [LT] Refluffing Mail and Plate as Plate over Mail?
 

These examples give a better idea of how the construction resembled lamellar.

https://upload.wikimedia.org/wikiped...7_of_27%29.jpg
https://s3-eu-west-1.amazonaws.com/l...27_540x360.jpg

The Romans solved the problem by replacing the lacing with staples.
http://edgegibbons.tripod.com/Squama...s/image003.jpg