A combination of factors: Excessively narrow beam, additional gun deck, resultant high centre-of-gravity, healing over, and then shipping water through gunport

A combination of factors: Excessively narrow beam, additional gun deck, resultant high centre-of-gravity, healing over, and then shipping water through gunports. Gunports are most usually open when guns are firing, which occurs as a ship is under way. Merely having open gunports should not imperil a ship. The Bayesian similarly had a high CoG and windage courtesy its tall mast, and was apparently susceptible to shipping water should it heel sharply and/or encounter high seas, as seems to have been the case.