Armour, weapons and tech.

Again, good believable tech level, and the silk can be traded for with China if we're lucky. Leather is available to us, through the tribes and metal should be accessible, or something we can trade for. The caparisoned boarding is what I had in mind really, once you described it, but could only think of the Mail kind when I posted. Lamellar has the added advantage over mail or othe armours in that it's is quieter. Less warning on fast raids!