Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

On wave-induced coupled motion during cooperative multi-crane lifting operation
with two vessels

Kazuhisa Otsubo
National Maritime Research Institute, JapanTokyo, JapanABSTRACT
To utilize the ocean space, i.e., the offshore oil and gas development, the renewable energy, crane lifting operations in theocean are crucial for constructing offshore structures and installing facilities on the seafloor, and safety and availability of
the crane lifting operation must be analyzed when planning construction. Wave-induced coupled dynamics between a vessel anda suspended load need to be predicted for these analyses as thecoupled dynamics can result in more complex mechanics. Cooperative multi-crane lifting operation with two vessels is often
selected in order to lift the heavy susp. load. The mechanics
in the cooperative multi-crane lifting with two vessels is more
complex than single crane operation with a vessel. A thoroughunderstanding of the coupled dynamical mechanics is required
when using a multi-crane lifting with two vessels. Unfortunately,
there’re few research activities regarding to the fundamental mechanics and the motion analysis in the multi-crane lifting operation with two vessels. Given these motivations, we conductedboth model experiment and numerical calculation to investigate
the wave-induced coupled dynamics during the multi-carne lifting operation with two different displacement vessels. We investigated the impact of the susp. load and the distance between
two vessels on the coupled dynamics.

KEY WORDS: cooperative multi-crane lifting operation; waveinduced motion; multibody dynamics; model experiment; numerical method;
INTRODUCTION
Crane lifting operations in the ocean are crucial for constructing offshore structures and installing subsea facilities on theseafloor. Safety and availability of the lifting operation must beanalyzed when planning the construction. Wave-induced coupled
dynamics between a vessel and a susp. load need to be predicted

for these analyses as the coupled dynamics can result in more
complex mechanics than just dynamics of a floating structures.
Cooperative multi-crane lifting operation with two vessels is often selected in order to lift the heavy susp. load (Winsen, 2019).
The mechanics in the cooperative multi-crane lifting with twovessels is more complex than single crane operation with a vessel. In such situation, the connection of the two vessels to thesusp. load means that all actions taken on one vessel influence
not only motions of the susp. load but also the another vessel.
Therefore, as DP system in these working vessels needs to be
designed optimally considering the such characteristic mechanics for safety position keeping, a thorough understanding of thecoupled dynamical mechanics is required when using the cooperative multi-crane lifting with two vessels.
As the wave-induced coupled dynamics between a vessel anda susp. load is classical problem in ocean engineering, many researchers already had conducted investigation to understand thefundamental mechanics for the large sized crane barge with thesusp. load in air. In particular, the research activities seem tobe concentrated from 1970’s to 1980’s because the large cranevessels were needed strongly for the marine construction. For
example, The Japan Workvessel Association conducted modelexperiments for large crane barges. Although useful experimental data were obtained, the theoretical investigation were notenough to understand the mechanics (The Japan Workvessel Association, 1978). Nojiri investigated the coupled dynamics inlinear analysis through model experiment and numerical calculation. (Nojiri, 1980, 1983). As the application research using
linear model, the operational limit analysis in the frequency domain was carried out in order to select the optimum crane vessel.
(Clauss, 1992, Wang, 2019). Researchers had started to apply
multibody dynamics theory and calculation methods (Tajima,2015) to the wave-induced coupled dynamics for various evaluation from 2000’s. (Jeong, 2016). Recently, the new calculation
method in which the combined multibody dynamics theory with653