Back in the day on Splendor of the Seas, we hit a squall and captain asked lunchers to sit on the port side only in the MDR, I kid you not. Deck doors were locked until further notice...lots of Henrys were mighty busy that night in the halls, closet I've ever come to getting sick, but it was exciting. Ships are designed to take 12% heels I believe the Chief once said. I have sailed a 27' Catalina sail boat standing straight up on the gunnels, we had a swing keel but she kept upright no problem. I highly suspect the heel was not 18*, it just feels like it. That's almost on her side!