Thanks for your input, B!!!
A pair of japanese war vessels from the Civil Wars era previous to the Tokunawa Shogunate:
The kobayabune or just kobaya, were small, fast and nimble oar (from 6 to up to 20 oars) warships.
The mid-size sekibune, were the most prevalent warship during that turbulent era. Only propelled by oars during combat, a large square sail was used for traslations without enemy at sight. The box-like superstructure was armed with cannons and japanese matchlock muskets.
The bigger vessels, the atakabune, were forbiden during the Shogunate and the dimensions were greatly exagerated in that late period. Cheers.