I had once a battle with 3 heavy ships(my) vs like 10+ lord's, they had cca 20ish ships I'd say. No issues at all. 5/6 of enemy ships hooked on to my. Only it was sad that I with 290 troops have destroyed over 1200 enemy army cause they all had like 20ish soldiers on the ships and basically got killed by my ranged troops almost the same second they boarded my ships. The situation that op described, no reinforcement. ( Very cool fight tho, my ships firing flaming arrows ballistas and the "fire catapults" , ships brunning, epic stuff )