This study investigates the ultimate strength of container ships under the combined action of vertical and horizontal bending moments. The ultimate strength of three container ships with different specifications is calculated using single-span finite element models, and the influence of loading sequence and path on the results is discussed. A revised failure envelope equation for the ultimate strength of ultra-large container ships under biaxial bending moments is proposed. Using finite element software, the stress-strain characteristics of stiffened panels are obtained, both with and without initial stresses. Based on this, the existing load-end shortening curve for stiffened panels is improved. A simplified incremental iterative method for calculating the hull girder's ultimate strength under biaxial bending moments is then proposed. A comparison between the results from the nonlinear finite element method and those from the proposed method demonstrates that the latter achieves high computational accuracy, along with simplicity of operation and ease of programming. The findings of this research can be applied to the calculation and analysis of the ultimate strength of container ship hull girders under biaxial bending moments.

Zooplankton nets are fundamental tools for biological oceanography, and their sampling quality directly affects the evaluation accuracy of species composition and ecological function. The technical evolution of zooplankton nets from early vertical hauls to modern multi-net platforms (such as MOCNESS and Multinet) has been reviewed to highlight significant advancements in mechanical control, telemetry, and depth-resolved sampling. It analyzes the complementary role of non-contact technologies, such as optics, acoustic, and environment DNA, to traditional nets, emphasizing the continuing necessity of net sampling in species identification and data verification. It is further proposed that the future development of zooplankton nets should integrate sensing systems, artificial intelligence, and sample-preservation technologies to develop a “smart net” system for efficient, low-bias and quantitative sampling of meso- and macro-zooplankton.

Island rescue vessels need to navigate shallow waters and dock at small piers on reefs, so their displacement is usually limited. The arrangement of various rescue equipment within a confined space is challenging, necessitating appropriate trade-offs. By establishing a quantitative assessment method for rescue capabilities, combined with the overall performance and rescue equipment configuration of different design schemes, the rescue capacity of the vessel can be evaluated in the early design phase to ensure it meets mission requirements. This assessment method has been successfully applied in the design of relevant island rescue vessels.

A set of shipboard helicopter integrated logistic support helicopter integrated logistic support(ILS) methods adapting to extreme environmental conditions, such as polar low temperature and icing, is proposed in order to meet the increasing requirements of ILS for helicopters on polar ships in China. The current common polar rules, standards and ship configuration are studied to identify their incompatibility with extreme polar environments. Targeted improvement plans are then proposed based on relevant domestic and international systems. These improved helicopter ILS methods for polar ships can be selectively applied to the design and construction of new generation polar ships.

The harsh natural environment and special geographical position of the polar regions make the polar activities more dangerous. Frequent sudden accidents also impose higher requirements for the emergency rescue in the polar regions. China has carried out a large number of scientific investigations and commercial shipping in the Antarctic and Arctic, but with weak foundation of polar rescue. By summarizing the current main rescue modes in the polar regions, a preliminary idea of the polar rescue system is proposed, and the organization structure, regulation study, platform construction, environmental survey, communication and navigation, rescue station distribution, equipment development, personnel training and procedure formulation are described. This study will fill the gap in the research of polar rescue system in China, in order to provide references for the establishment of the polar rescue system in the future.

Public affair vessels will transfer persons and supplies during the missions at sea. The ship-to-ship personnel transfer and matexial supply are the most direct ways for two ships berthing together. While the selection of fenders plays an important role for safe ship-to-ship operation. This article analyzes and studies the calculation and type selection method commonly used for the fenders of transport ships during the ship-to-ship operation. The type selection and calculation method of the fender for public affair vessels are proposed based on the characteristics of the ship-to-ship operation of public affair vessels, combined with the type of the fender. It can also provide guidance for the selection of the impact energy calculation formula during the ship-to-ship operation.

This article focuses on the working efficiency of the scientific research ship with modular loads (mainly the research containers). The gain of modular loads to the work efficiency is analyzed through the comparison of the service situations of the scientific research ship with the different carrying capacities during one single voyage and the whole year. The ship borne research modular moving system is suggested to be equipped on the scientific research ship according to the increasing modularity.

The underwater operations of two cables are simulated and analyzed by Matlab together with the simulation analysis method of the rigid body dynamics based on the finite element method (FEM) that has been widely used in the hull structural design. The obtained variation of the cable posture with time can determine whether the double cable will interfere with each other underwater. It firstly analyzes the influence of the ship motion on the cable launching point, and then builds the dynamical model for the cables underwater. Finally, the cable posture underwater is obtained through the simulation.

Long gravity piston corer is one of the most common sampling operation on research vessels for geological survey. It focuses on the launch and recovery technique for the long gravity piston corer. Firstly, it briefly introduces the operation principle and working procedure of the corer sampling. Then, it compares the launch and recovery techniques and implementation schemes of several long gravity piston corers, and provides some foresighted suggestions.