Blockade Sampler. These resemble the tubular sampler except the 

 sample is taken horizontally and features a messenger-activated closing device 

 which moves over the mouth of the sampling tube to prevent the captured 

 sample from being washed away during recovery. 



Rectangular Box Sediment Sampler. This sampler consists of an 

 open-bottom, rectangular-shaped box mounted at the end of a sturdy sliding 

 vertical bar. A triggering mechanism permits the sampler to plunge into the 

 bottom. A lever mechanism permits closure of the bottom end upon initia- 

 tion of withdrawal. This sampler provides an undisturbed sample for tests 

 and analyses of stratification of the near-surface layers. This device causes 

 less disturbance than the other samplers mentioned above. 



Biological and Water Samplers 



Table B-7 includes the various available instruments for collecting 

 biological and water samples. The specific instrument to be used for a 

 particular survey will be dictated by the requirements and scope of the 

 seafloor structure. 



Further research is required in this area of biological and water 

 sampling to determine parameters which are responsible for the initial causes 

 of corrosion and fouling. Once these causes are identified, a particular instru- 

 ment listed may be applicable to sample collection. 



Underwater Cameras and Lights 



Tables B-8 and B-9 are listings of underwater cameras and lights, 

 respectively. Some of these instruments are designed into a package that 

 will also permit taking grab samples of the seafloor. 



The camera— light system for use in a particular survey is dictated by 

 the scope and requirements of the particular structure. For example, the use 

 of these instruments in stereo mapping applications will require special lens 

 designs to eliminate distortions. The use of color and range gating techniques 

 would also require special considerations in design. The design of a particular 

 camera system would therefore require the services of personnel experienced 

 in that particular field of application. 



Oceanographic Research Vessels 



Table C-1 lists the various surface oceanographic research vessels being 

 used by U.S. Government agencies and universities. The information on most 

 vessels in the table was obtained from publications on oceanographic vessels 



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