Light Buoy Research Articles

操船シミュレータ上の灯火の表現手法と関門航路への適用

We have aimed to improve safety of ship navigation at night and studied appropriate passage routes on ship handling simulator taking Kanmon Passage as an example. As we enhance recognition of the passage route, we prepared several ways such as changing character of light buoys or corresponding/cascading buoys lighting. We have represented lights of aids to navigation such as buoys and lighthouses accurately in our ship handling simulator and executed simulator experiments to test those ways. To represent accurate representation of lights, we have made several CGI (Computer Graphics Imagery) objects based on their colors, their luminosity and luminance of CGI on screen. A buoy chooses appropriate object automatically from them according to its own luminosity and a distance between the buoy and a viewpoint. Besides we have added equations of atmospheric transmittance to our program and realized visibility of light on our simulator. We discuss those methods and results of the simulator experiments in this paper.

カラーネーミング法による航海用灯火ブイの色評価

カラーネーミング法による航海用灯火ブイの色評価

Fluctuations in the Reflectivity of the Ocean Surface

An experiment was performed in a deep-ocean basin to investigate the reflectivity of the ocean surface. Acoustic pulses were produced at depths ranging from 500 to 3000 ft and received on hydrophones at a variety of depths and horizontal ranges. The pulses were produced by gating 60-msec bursts of sine waves into sources having resonant frequencies of 170, 400, 600, and 1300 cps. Simultaneous measurements of the ocean-surface waves were made with light buoys (Splashniks) which carried accelerometers. The level of the reflected acoustic energy varies markedly from pulse to pulse. Autocorrelation of successive levels yields a power spectrum which resembles that of the ocean waves. Defining fluctuation as the ratio of the standard deviation of ∫ρ2dt to the average value of ∫ρ2dt, we find that fluctuation increases with acoustic frequency, approaching a saturation value of about 100% when the acoustic wavelength is 4 times the product of the rms height of the ocean waves and the cosine of the angle of incidence θ. Below saturation, the fluctuation is proportional to (cos θ)n, where 0.75<n<1.53 and where n decreases with increasing frequency. [Columbia University, Hudson Laboratories Informal Documentation No. 5. This work was supported by the Office of Naval Research.]

瀬戸内海掃海水路灯浮標について(日本航海学会第13回講演会)

Light buoys are very important for navigation, and especially so in Swept Channels in The Inland Sea of Seto. In order to make light buoys arrangement more effective, many efforts have been paid. However, there are still many unsolved problems and some examples about light buoys in 1954 and 1955 particularly on their defects and inadequate positioning are described here. Further some proposals for the rationalization of their operation between Osaka to He Saki are discussed.

Obituary Notices

WE regret to announce the following deaths: Dr. N. Gustaf Dalén, inventor of automatic regulators for use in conjunction with gas accumulators for lighting lighthouses and light buoys, for which he received the Nobel Prize in Physics in 1912, on December 10, aged sixty-eight years.

Aids to Navigation: Stationary and Floating Lights, with a Detailed Description of the Foster Compressed Gas System, as Applied to Light Towers, Buoys, Torpedo and Submarine Boats

Aids to Navigation: Stationary and Floating Lights, with a Detailed Description of the Foster Compressed Gas System, as Applied to Light Towers, Buoys, Torpedo and Submarine Boats