The big swells invade the Toyama Bay from October to March as usual, and cause wave disasters repeatedly since long ago on the coast of Toyama bay. Furthermore, LNG cargo handling is carried out regularly in Toyama New Port, and it is dangerous because, swells invaded the port give bad influence to the cargo handling. Therefore, it is important to investigate swells invaded the port. And so, we investigated swells in the Toyama New Port by the comparison of swells off and in the port. Summaries of obtained results are as follows.

(1)The shapes of wave spectra in the port are different from those off the port.

(2)The shapes of wave spectra in the port are almost the same, independently of shapes of wave spectra off the port.

(3)Attenuation rates of swells with about 14 second, about 13 second and about 11 second period, which invaded Toyama New Port, are smaller than those of swells with other periods which invaded the port.

It was shown that wave height of long period wave with about 30 minute period, which invaded Toyama New Port, increases four times compared to the wave height before invading the port in another study. Furthermore, it was shown that attenuation rates of swells, which invaded the port, are different depending on those wave periods in this paper. The authors consider that the cause that the attenuation rates of swells are different depending on the wave periods, is that wave heights of swells with particular periods which invaded the port, increase at the end of the port. It is a future problem to make clear the generating mechanism of those phenomena.

Surveys of lake and seafloor sediments and topography are very important for improving fisheries catches and elucidating the mechanisms of earthquake occurrence. In order to carry out such surveys, it is necessary to develop a survey boat that can navigate even in relatively shallow and difficult-to-enter waters. In this research, we developed a compact and lightweight self-navigation survey boat that is easy to disassemble and carry. The research vessel we developed consists of a motor, a fish-finder, and a microcomputer (Raspberry Pi). In order to realize the proposed survey boat, we developed a new self-navigation control algorithm and conducted a practical experiment in the ocean to confirm its superiority.

In this study, we conducted a basic research on the possibility of creating reference data by inputting data measured by a low-cost sensor into the input value of the Trajectory Generator (TG) used for testing the Inertial Navigation System (INS). By adjusting the speed at 1 [Hz], the maximum and average errors in the horizontal direction were 4.31 [m] and 0.36 [m], respectively. In the altitude, both the maximum and average errors were 12.69[m] and 3.69[m]. This result shows that reference data including acceleration and gyroscope sensor can be estimated using only low-cost sensors, although with the conditions mentioned in the paper. We believe that this will be a very important tool for future research and development.

In the 2011 Tohoku earthquake and tsunami, a lot of sea disasters of ships moored along terminal inside harbor basins occurred. In order to make a countermeasure for the disasters, it is considered as a practical measure to strengthen the mooring line property of ship. In this paper, a physical model test on dynamic behavior of a moored ship which is a modeled 90,000DWT class coal carrier affected by the disaster, has been conducted in two-dimensional water tank during a tsunami bore. The surface elevation, current, motions and mooring loads of the ship have been measured in stern sea. The effect of the mooring line property and its pretension on the ship’s behavior and mooring loads during tsunami bore have been investigated.

Assessing the location and frequency of potential collisions is important to prevent collision accidents. The collision causation probability, which is an index of a collision frequency model, effectively expresses the collision possibility statistically. While it had assessed ship traffic with a certain encounter angle such as in traffic separation routes, it has become capable of assessing ship traffic in congested waters corresponding to encounter angles.

This paper presents the estimation of the collision causation probability depending on the waters and encounters, such as overtaking, head-on, and crossing situations, using a collision frequency model. The results include the comparison to a conventional probability and current trend depending on the waters and encounters.

Authors are studying and developing the higher holding performance new type anchor to prevent the marine accident due to the dragging anchor. The purpose of this research is to indicate the usefulness and applicability of our higher holding performance new type anchor in actual sea area. For that purpose, the actual sea model tests were carried out in September and November 2019. Shioji-maru, the training ship belonging to the TUMSAT, was used for the actual sea model tests. The actual sea model tests were carried in Tateyama Bay and Off Tokyo Bay Urayasu. The dragging tests were carried out in the actual sea areas and, the basic holding performance of the new type model anchor was verified. In this paper, it is considered the holding resistance, the holding resistance coefficient, and stability. From this consideration, it was revealed that the new type anchor has the possibility and usefulness as the higher performance new type anchor of the next generation. In addition, the issues for practical use were shown.

Nankai Trough Earthquake with the huge tsunami is said to have a high chance of occurring in the future, appropriate tsunami countermeasures for vessels in ports are needed. Thus, it is important that tsunami damages of vessels in each port are quantitatively predicted according to certain standards. The purpose of this study is to predict tsunami damages of vessels moored at wharves at Japanese major ports and make “tsunami hazard database for vessels” which evaluate breaking the mooring lines and landed on a wharf from parameters such as vessels data, estimated tsunami heights and crown heights at each port. As a result, it is indicated that the tsunami hazard database is able to predict the tsunami damages of mooring vessels in Japanese major ports.

Passenger cars, trucks, and construction machinery that are shipping by PCTC are becoming larger year by year with the needs of the times. And the cargo weight is increasing too.

The design deck strength of PCTC is determined for each deck. It is extremely important for hull maintenance and safe voyage to consider whether or not loading is possible at the stage of making a loading plan.

In this study, we focused on SUV, which are larger among passenger cars. Then, based on the design deck strength, the possibility of loading was considering.

At first, the SUV and the loading environment were modeled, and the amount of deck deflection was calculated by the allowable stress design method.

Next, the amount of deflection of the deck was actually measured on the actual PCTC under the same condition.

Finally, we presented the three conditions necessary to determine whether or not to load.