Capsize of ship models in following/quartering waves: physical experiments and nonlinear dynamics

Abstract

This paper presents experimental records for capsizing of ship models in following and quartering seas. Recorded capsizes have been classi ed into four modes: broaching, low cycle resonance, stability loss on a wave crest, and bow diving. Nonlinear dynamics were applied to broaching and low cycle resonance to reveal their qualitative and quantitative characteristics. For other modes, further investigation based on nonlinear dynamics should be encouraged.

Broaching-to prevention in real-time using momentary state feedback control focusing on the saddle point in the system

“…Before moving to simulation in irregular wave, investigating the effectiveness of this approach for more regular wave conditions and extending to irregular waves using a probabilistic approach will be carried out. Furthermore, for preventing dangerous phenomena with larger heading in stern quartering waves with higher speed, it should be investigated together with yaw-roll instability without surfriding and the bow-diving phenomena [23] in the future.…”

Chaotic roll motions of ships in regular longitudinal waves

“…The kinematic energy delivered by the waves exciting the pitch motion of the ship is partly transferred to the roll motion so that the roll amplitude grows gradually while the pitch amplitude remains constant. Hang et al(1999) constructed an equivalent linearised differential equation of the rolling motion, and used Laplace transformation to find the safe region and unsafe region of the ship in longitudinal waves, Umeda and Hamamoto (2000); Umeda and petrer (2002) classified the ship capsizing in following and quartering seas into four modes: broaching, low cycle resonance, stability loss on a wave crest, and bow diving, and used nonlinear dynamics method to reveal the qualitative and quantitative characteristics of ships in low cycle resonance and broaching. Their research also find that before a ship capsizes it will have a chaotic motion, and in these conditions the ship's motion becomes unstable and unsafe, easy to capsize.…”