K. Ohta, K. Ohkawa, K. Asano, S. Hibi, H. Takahashi
The interface wave is known as a useful tool to study geoacoustic properties and can be conventionally generated by setting up an explosive or a pneumatic source on/above the seafloor. This type of source, however, also excites strong compressional waves in the water and sediment, and so the generated interface wave is affected by this compressional wave, resulting in difficulty in processing. The waves generated in this way are also poor in duality and those sources may cause environmental problems. To solve this, we tried to utilize an electromagnetic induction source, called Boomer, which is generally used in the water as a source for generating compressional waves. First, we fabricated a Boomer with several types of vibrator plates on a small scale. To evaluate the performance of the source, the sound pressure level exited by the source was measured in a water tank and was compared with a designed one. Then we drove the source with the vibrator plates on the seafloor and evaluated the properties of the generated interface wave, which observed by a geophone, and compared the measured wave signal with one generated by dropping a weight. Consequently, the electromagnetic induction source turns out to be useful for generating an interface wave having repeatability.
{"title":"Generating interface wave using electromagnetic induction source","authors":"K. Ohta, K. Ohkawa, K. Asano, S. Hibi, H. Takahashi","doi":"10.1109/UT.2000.852517","DOIUrl":"https://doi.org/10.1109/UT.2000.852517","url":null,"abstract":"The interface wave is known as a useful tool to study geoacoustic properties and can be conventionally generated by setting up an explosive or a pneumatic source on/above the seafloor. This type of source, however, also excites strong compressional waves in the water and sediment, and so the generated interface wave is affected by this compressional wave, resulting in difficulty in processing. The waves generated in this way are also poor in duality and those sources may cause environmental problems. To solve this, we tried to utilize an electromagnetic induction source, called Boomer, which is generally used in the water as a source for generating compressional waves. First, we fabricated a Boomer with several types of vibrator plates on a small scale. To evaluate the performance of the source, the sound pressure level exited by the source was measured in a water tank and was compared with a designed one. Then we drove the source with the vibrator plates on the seafloor and evaluated the properties of the generated interface wave, which observed by a geophone, and compared the measured wave signal with one generated by dropping a weight. Consequently, the electromagnetic induction source turns out to be useful for generating an interface wave having repeatability.","PeriodicalId":397110,"journal":{"name":"Proceedings of the 2000 International Symposium on Underwater Technology (Cat. No.00EX418)","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125903235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Joseph, R. White, T. Bethge, J. Palshook, C. Ingram, B. Rumish
The Naval Oceanographic Office (NAVOCEANO) and Nauticos Corporation conducted a Seamap-C survey that delineated small regions of high reflectivity material in an abyssal plain northwest of Midway Atoll. The survey in the Midway area was based on a Nauticos Corporation RENAV/sup TM/ analysis of the possible location of the Japanese carrier, Kaga, sunk during the Battle of Midway in June, 1942. Seamap-C imaged three potential targets for further investigation with the higher frequency EG&G 960 system. A subsequent operation in the Midway area was conducted some months later using NAVOCEANO's Towed Oceanographic Survey System with higher resolution sidescan sonar (50/500 kHz), video cameras, and digital still photography. The optical survey identified a debris field, composed of twisted wreckage and the associated debris from one of the Japanese aircraft carriers sunk during the Battle of Midway.
{"title":"Using the NAVOCEANO wide swath sidescan sonar Seamap-C to locate and differentiate man-made objects from natural features on the seafloor","authors":"D. Joseph, R. White, T. Bethge, J. Palshook, C. Ingram, B. Rumish","doi":"10.1109/UT.2000.852512","DOIUrl":"https://doi.org/10.1109/UT.2000.852512","url":null,"abstract":"The Naval Oceanographic Office (NAVOCEANO) and Nauticos Corporation conducted a Seamap-C survey that delineated small regions of high reflectivity material in an abyssal plain northwest of Midway Atoll. The survey in the Midway area was based on a Nauticos Corporation RENAV/sup TM/ analysis of the possible location of the Japanese carrier, Kaga, sunk during the Battle of Midway in June, 1942. Seamap-C imaged three potential targets for further investigation with the higher frequency EG&G 960 system. A subsequent operation in the Midway area was conducted some months later using NAVOCEANO's Towed Oceanographic Survey System with higher resolution sidescan sonar (50/500 kHz), video cameras, and digital still photography. The optical survey identified a debris field, composed of twisted wreckage and the associated debris from one of the Japanese aircraft carriers sunk during the Battle of Midway.","PeriodicalId":397110,"journal":{"name":"Proceedings of the 2000 International Symposium on Underwater Technology (Cat. No.00EX418)","volume":"104 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115724705","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We have developed an autonomous underwater vehicle (AUV), which can be used for lake environment monitoring. The length of the AUV is 2 m, its weight in air is 180 kg, and its maximum speed in water is 2 knots. It has two major missions: one is to monitor plankton distribution in the epilimnion by using its on-board submersible microscope, and the other is to monitor water quality in the benthic boundary layer by using a CTD instrument equipped with multiple sensors. The obtained data and images are transmitted to a surface research vessel (R/V) by ultrasonic waves, and subsequently transferred from the R/V to our base institute (Lake Biwa Research Institute) by a satellite mobile phone data link. We are expecting that this AUV will contribute to solving serious problems occurring in Lake Biwa such as cyanobacteria blooms in the epilimnion, and oxygen depletion in the benthic boundary.
{"title":"New AUV designed for lake environment monitoring","authors":"M. Kumagai, T. Ura, Y. Kuroda, R. Walker","doi":"10.1109/UT.2000.852519","DOIUrl":"https://doi.org/10.1109/UT.2000.852519","url":null,"abstract":"We have developed an autonomous underwater vehicle (AUV), which can be used for lake environment monitoring. The length of the AUV is 2 m, its weight in air is 180 kg, and its maximum speed in water is 2 knots. It has two major missions: one is to monitor plankton distribution in the epilimnion by using its on-board submersible microscope, and the other is to monitor water quality in the benthic boundary layer by using a CTD instrument equipped with multiple sensors. The obtained data and images are transmitted to a surface research vessel (R/V) by ultrasonic waves, and subsequently transferred from the R/V to our base institute (Lake Biwa Research Institute) by a satellite mobile phone data link. We are expecting that this AUV will contribute to solving serious problems occurring in Lake Biwa such as cyanobacteria blooms in the epilimnion, and oxygen depletion in the benthic boundary.","PeriodicalId":397110,"journal":{"name":"Proceedings of the 2000 International Symposium on Underwater Technology (Cat. No.00EX418)","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125174195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Unexpectedly high underwater electric field (UEF) signatures of ships have been reported, and detection of ships by their UEF signatures is known to be effective. For the purpose of cost-effective and reliable method to estimate UEF signatures of actual ships in open sea, we developed a method to measure underwater electric potential (UEP) from the deck of the ship. Two reference electrodes were hung down into water from the deck side. By fixing one of the electrodes near the stem of the ship, we measured the UEP at several points by another electrode around the ship in the depth of one meter. We then measured the UEP for the two ships, and the ratio of UEP of two ships agreed with that of UEF signatures measured with the sensors on the seafloor. We confirmed that the proposed method to measure UEP of actual ships is effective.
{"title":"A method to measure ship's underwater electric field from deck","authors":"M. Hirota","doi":"10.1109/UT.2000.852547","DOIUrl":"https://doi.org/10.1109/UT.2000.852547","url":null,"abstract":"Unexpectedly high underwater electric field (UEF) signatures of ships have been reported, and detection of ships by their UEF signatures is known to be effective. For the purpose of cost-effective and reliable method to estimate UEF signatures of actual ships in open sea, we developed a method to measure underwater electric potential (UEP) from the deck of the ship. Two reference electrodes were hung down into water from the deck side. By fixing one of the electrodes near the stem of the ship, we measured the UEP at several points by another electrode around the ship in the depth of one meter. We then measured the UEP for the two ships, and the ratio of UEP of two ships agreed with that of UEF signatures measured with the sensors on the seafloor. We confirmed that the proposed method to measure UEP of actual ships is effective.","PeriodicalId":397110,"journal":{"name":"Proceedings of the 2000 International Symposium on Underwater Technology (Cat. No.00EX418)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129289656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Gaiffe, Y. Cottreau, N. Faussot, G. Hardy, P. Simonpiétri, H. Arditty
Octans is a fiber-optic gyrocompass with an integral motion sensor developed by Photonetics for demanding marine applications. In contrast with conventional gyrocompasses relying on a spinning gyroscope, Octans has no moving parts and utilizes instead three fiber optic gyroscopes (FOG) and three quartz accelerometers. The FOG technology is based on the relativistic Sagnac effect: light travels in opposite directions into a fiber optic coil, and interferes at the output with a phase-shift proportional to the rotation rate. Moreover, three accelerometers measure, after Schuler filtering, the local gravity vector. As the FOGs are enough accurate (typically a bias stability of 0,05 /spl deg//h), the observation of the gravity slow drift in the inertial space allows one to determine the Earth axis, thus the North direction. In addition, the real three-axis architecture allows Octans to act as a marine motion sensor and compute the complete attitude of the vessel in terms of roll, pitch, heave, surge and sway. Because of a specific algorithm, Octans is able to find the true heading without any help in three minutes even at sea. This system is obviously ideal for ROVs and AUVs applications: low power consumption, compact, light box and very low settling time.
{"title":"Highly compact fiber optic gyrocompass for applications at depths up to 3000 meters","authors":"T. Gaiffe, Y. Cottreau, N. Faussot, G. Hardy, P. Simonpiétri, H. Arditty","doi":"10.1109/UT.2000.852533","DOIUrl":"https://doi.org/10.1109/UT.2000.852533","url":null,"abstract":"Octans is a fiber-optic gyrocompass with an integral motion sensor developed by Photonetics for demanding marine applications. In contrast with conventional gyrocompasses relying on a spinning gyroscope, Octans has no moving parts and utilizes instead three fiber optic gyroscopes (FOG) and three quartz accelerometers. The FOG technology is based on the relativistic Sagnac effect: light travels in opposite directions into a fiber optic coil, and interferes at the output with a phase-shift proportional to the rotation rate. Moreover, three accelerometers measure, after Schuler filtering, the local gravity vector. As the FOGs are enough accurate (typically a bias stability of 0,05 /spl deg//h), the observation of the gravity slow drift in the inertial space allows one to determine the Earth axis, thus the North direction. In addition, the real three-axis architecture allows Octans to act as a marine motion sensor and compute the complete attitude of the vessel in terms of roll, pitch, heave, surge and sway. Because of a specific algorithm, Octans is able to find the true heading without any help in three minutes even at sea. This system is obviously ideal for ROVs and AUVs applications: low power consumption, compact, light box and very low settling time.","PeriodicalId":397110,"journal":{"name":"Proceedings of the 2000 International Symposium on Underwater Technology (Cat. No.00EX418)","volume":"38 5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130842225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
It has been proposed to use gravitational field maps to correct navigational errors inherent in some navigational systems presently in use on unmanned underwater vehicles (UUV) and that such a technology might form the basis for a new UUV navigational system. However, the accuracy and usefulness of the navigational solution depends, among other things, on the accuracy of the gravitational field maps. Since gravitational fields are generally sparsely and irregularly sampled, mapping algorithms must be used to construct the field maps. To assess the impact of field maps computed from sparse sets of data on the accuracy of the navigational solution, the kriging algorithm is used to compute field maps with various grid spacings from both simulated and measured field data. Then position and bearing errors are simulated and the various field maps are used to obtain corrected navigational fixes. To assess the impact of the density of the field data on the accuracy of the navigational fix, the simulated data are sub-sampled and the process is repeated. Numerical results are shown that demonstrate some of the effects of grid spacing and data density on the accuracy of the navigational fix and that gravitational field maps may be used to provide a very accurate navigational fix.
{"title":"Gravitational field maps and navigational errors","authors":"G. Bishop","doi":"10.1109/UT.2000.852532","DOIUrl":"https://doi.org/10.1109/UT.2000.852532","url":null,"abstract":"It has been proposed to use gravitational field maps to correct navigational errors inherent in some navigational systems presently in use on unmanned underwater vehicles (UUV) and that such a technology might form the basis for a new UUV navigational system. However, the accuracy and usefulness of the navigational solution depends, among other things, on the accuracy of the gravitational field maps. Since gravitational fields are generally sparsely and irregularly sampled, mapping algorithms must be used to construct the field maps. To assess the impact of field maps computed from sparse sets of data on the accuracy of the navigational solution, the kriging algorithm is used to compute field maps with various grid spacings from both simulated and measured field data. Then position and bearing errors are simulated and the various field maps are used to obtain corrected navigational fixes. To assess the impact of the density of the field data on the accuracy of the navigational fix, the simulated data are sub-sampled and the process is repeated. Numerical results are shown that demonstrate some of the effects of grid spacing and data density on the accuracy of the navigational fix and that gravitational field maps may be used to provide a very accurate navigational fix.","PeriodicalId":397110,"journal":{"name":"Proceedings of the 2000 International Symposium on Underwater Technology (Cat. No.00EX418)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129209186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Proposes a method for underwater target tracking using optical data, which consists of color, texture, shape and dynamic properties of the environment. Here, how the dynamic properties from image sequences can be used for target tracking by autonomous underwater vehicles (AUVs) is studied. Optical flow techniques are used to derive the dynamics of the images. The objects of interest are extracted from the images by using the dynamical properties and their optical features. The consecutive dynamic behavior of objects of interest is estimated based on the current dynamics. Using the predicted dynamics, the region of interest (ROI) in the image can be identified reducing the amount of data to be processed. This increases the speed of processing using the hardware available in small pressure hulls. Image dynamics and feature position information fused with other on-board sensor information, the navigational commands for the AUV are derived. In the paper, the extraction of objects of interest from the images based on dynamic vision is presented and the performance of this method for underwater target tracking is demonstrated by experimental results.
{"title":"Autonomous target tracking by AUVs using dynamic vision","authors":"Yang Fan, Arjuna Balasuriya","doi":"10.1109/UT.2000.852539","DOIUrl":"https://doi.org/10.1109/UT.2000.852539","url":null,"abstract":"Proposes a method for underwater target tracking using optical data, which consists of color, texture, shape and dynamic properties of the environment. Here, how the dynamic properties from image sequences can be used for target tracking by autonomous underwater vehicles (AUVs) is studied. Optical flow techniques are used to derive the dynamics of the images. The objects of interest are extracted from the images by using the dynamical properties and their optical features. The consecutive dynamic behavior of objects of interest is estimated based on the current dynamics. Using the predicted dynamics, the region of interest (ROI) in the image can be identified reducing the amount of data to be processed. This increases the speed of processing using the hardware available in small pressure hulls. Image dynamics and feature position information fused with other on-board sensor information, the navigational commands for the AUV are derived. In the paper, the extraction of objects of interest from the images based on dynamic vision is presented and the performance of this method for underwater target tracking is demonstrated by experimental results.","PeriodicalId":397110,"journal":{"name":"Proceedings of the 2000 International Symposium on Underwater Technology (Cat. No.00EX418)","volume":"463 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122358206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wavelet analysis theory is a new theory developed in recent years. It is a new time-frequency localization methods. As its analyzing precision can be changed and focused to any detail of the analyzed signal,it is very useful to study nonstationary signals. In this paper, we mainly study the wavelet theory and its application to control system. Furthermore, we use it to detect the fault of underwater vehicle's navigation angle fault, and its simulation results are given at the end of the paper.
{"title":"Wavelet transform and its application to autonomous underwater vehicle control system fault detection","authors":"Xu Dermin, G. Lei","doi":"10.1109/UT.2000.852523","DOIUrl":"https://doi.org/10.1109/UT.2000.852523","url":null,"abstract":"Wavelet analysis theory is a new theory developed in recent years. It is a new time-frequency localization methods. As its analyzing precision can be changed and focused to any detail of the analyzed signal,it is very useful to study nonstationary signals. In this paper, we mainly study the wavelet theory and its application to control system. Furthermore, we use it to detect the fault of underwater vehicle's navigation angle fault, and its simulation results are given at the end of the paper.","PeriodicalId":397110,"journal":{"name":"Proceedings of the 2000 International Symposium on Underwater Technology (Cat. No.00EX418)","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123043284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
TUBA is a towed undulating bio-acoustic instrument, developed at the Southampton Oceanography Centre, to enable the study of zooplankton using seven frequencies covering the range 175 kHz to 2.4 MHz. In TUBA II a significant advancement is the adoption of the 2-wire I/sup 2/C serial communications protocol to allow configuration and control of the instrument over as much as 1300 m of cable. This allows the control of parameters including receiver filter Q and bandwidth, transmit power, pulse width, transmission centre frequencies, and routing of test signals through the receiver stages to check internal noise levels and filter responses. As well as allowing greater control of the unit during scientific experiments, we have greater control during calibration exercises whether in the laboratory, or at sea. Further improvements include new wideband linear power amplifiers, improved receiver circuitry and filtering, and redesigned transducers using modern composite materials for greater sensitivity at the higher frequencies.
{"title":"Tuba II-a compact multi-frequency sonar suited to use in autonomous or towed platforms for the study of upper-ocean zooplankton distribution and abundance","authors":"N. Crisp, A. Harris","doi":"10.1109/UT.2000.852585","DOIUrl":"https://doi.org/10.1109/UT.2000.852585","url":null,"abstract":"TUBA is a towed undulating bio-acoustic instrument, developed at the Southampton Oceanography Centre, to enable the study of zooplankton using seven frequencies covering the range 175 kHz to 2.4 MHz. In TUBA II a significant advancement is the adoption of the 2-wire I/sup 2/C serial communications protocol to allow configuration and control of the instrument over as much as 1300 m of cable. This allows the control of parameters including receiver filter Q and bandwidth, transmit power, pulse width, transmission centre frequencies, and routing of test signals through the receiver stages to check internal noise levels and filter responses. As well as allowing greater control of the unit during scientific experiments, we have greater control during calibration exercises whether in the laboratory, or at sea. Further improvements include new wideband linear power amplifiers, improved receiver circuitry and filtering, and redesigned transducers using modern composite materials for greater sensitivity at the higher frequencies.","PeriodicalId":397110,"journal":{"name":"Proceedings of the 2000 International Symposium on Underwater Technology (Cat. No.00EX418)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127821383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The rubble leveling that accompanies the base mound construction for breakwaters and embankments takes place in demanding underwater environments involving extremely high risks. There is also concern about labor shortages and aging of divers. Moreover, harbor development sites have extended farther offshore in recent years, making it necessary to cope with more treacherous weather and deep-water conditions. Under these circumstances, in efforts to ensure safety and to shorten the process by speeding up operations, the demand for a safe underwater construction machine that can perform such tasks has been growing. In response to such demands, the "underwater backhoe", which mechanizes manual work performed by divers, has been developed. The device excels at tasks such as armor-stone leveling and rubble leveling required for base mound construction for breakwaters and embankments. This paper provides a background of underwater backhoe development and presents an overview of existing backhoes. It also introduces several instances of use in underwater work and considers several problems and areas for improvement.
{"title":"The development and utilization of the \"underwater backhoe,\" a multifunctional underwater construction machine","authors":"M. Ishii, S. Oshiro, T. Itoh","doi":"10.1109/UT.2000.852564","DOIUrl":"https://doi.org/10.1109/UT.2000.852564","url":null,"abstract":"The rubble leveling that accompanies the base mound construction for breakwaters and embankments takes place in demanding underwater environments involving extremely high risks. There is also concern about labor shortages and aging of divers. Moreover, harbor development sites have extended farther offshore in recent years, making it necessary to cope with more treacherous weather and deep-water conditions. Under these circumstances, in efforts to ensure safety and to shorten the process by speeding up operations, the demand for a safe underwater construction machine that can perform such tasks has been growing. In response to such demands, the \"underwater backhoe\", which mechanizes manual work performed by divers, has been developed. The device excels at tasks such as armor-stone leveling and rubble leveling required for base mound construction for breakwaters and embankments. This paper provides a background of underwater backhoe development and presents an overview of existing backhoes. It also introduces several instances of use in underwater work and considers several problems and areas for improvement.","PeriodicalId":397110,"journal":{"name":"Proceedings of the 2000 International Symposium on Underwater Technology (Cat. No.00EX418)","volume":"120 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115463455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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