 These vessels, more floating batteries than ships, were armed with multiple cannons and large caliber arquebuses, and were described by the Italian Jesuit Organtino as being protected by iron plates two to three inches thick.No iron-covering at all, however, was mentioned in the account of the Jesuit missionary Luís Fróis, who had also seen and described the ships.Nobunaga defeated the navy of his enemy Mōri Terumoto with these ships at the mouth of the Kizu River, Osaka in 1578 with a successful naval blockade.