NSWC/WOL/TR 75-3 5 



the medium: (1) gravity (weight or hydraulic piston), (2) vibrator 

 (pneumatic and electric), (3) explosive (chemical and electric 

 spark), (4) rotary (hydraulic and direct mechanical), and (5) scuba 

 divers inserting cores by hand. Among them, the gravity corer is 

 most commonly used for general purpose sampling. 



The sediment cores collected are immediately extruded and 

 sliced into sections. Each section is squeezed to remove residual 

 water and stored in appropriate containers (Section 3.1.5). 



3.2.3 Samplers 



There are close to one-hundred different sediment samplers 

 commercially available with price ranging from $30 to $4,000. Many 

 are designed for specific purposes. Others can be used for general 

 purposes. Since there is no "ideal" sampler, selection of an 

 appropriate sampler must depend on the requirements of the program. 

 Considerations should be given to: 



1. Types of sediment to be sampled. 



2. Depth of the water above the sampling site. 



3. Importance of undisturbed, unwashed samples. 



4. Introduction of contaminant to the samples. 



5. Size and weight of the samples. 



6. Requirements for support equipment on board ship. 



7. Ease of removal of the sample from the unit. 



8. Cost of the unit. 



Three types of sediment samplers are recommended for the 

 explosive testing program: 



(1) Van Dorn Sampler - Van Dorn sampler, normally used as a 

 water sampler, can be used for sampling suspended and unconsolidated 

 sediment. The description of the Van Dorn sampler is presented in 

 Section 3.1.3. 



(2) Shipek Sediment Sampler, Model 860 

 (Hydro Products, San Diego, California) - Fig. 6 



Specifications 



Size: 18.6 in. x 17.4 in. x 25.1 in. 



Weight: 134 lbs 



Materials: Sampler: cast iron 



Springs: tempered stainless 

 steel 



28 



