for the land and brown water rules, this might sound lazy, but i'll probably just try to adapt WH40k rules using guard-i mean astra militarum...nope an old guard codex for weapons info and what not. i'll probably remove armor saves just because no one back then wore armor.
boats will be treated like vehicles, land will be inpassable terrain, shallows might count as crossing difficult terrain.
for the blue water or green water naval battles, i'm still looking for rules.
but i'll keep posting links for interesting model lines and what not for the time period i find here if anyone else gets interested