15 lbs & 25 lbs Bottom Dredge

The 15 lbs Bottom Dredge features all stainless components except for the closing arms and integral weights which are made from powder coated carbon steel. The top of the sampling chamber is screened to allow water flow during deployment and reduce the frontal shock wave that may displace sediment and
allow sample loss on contact with the surface to be sampled. A two-way spring loaded mechanism activates the dredge on contact with the bottom, no messenger is needed.  Sampling area is 36 square inches with a 6" x 6" jaw opening.

The 25 lbs Bottom Dredge is constructed from stainless steel and powder coated carbon steel for corrosion resistance. The upper screens allow water flow during deployment and avoid displacement and shock wave effects that may cause sample loss.

One of the jaws is fitted with an under lip to displace stones or gravel during closure. A two way spring loaded mechanism activates on contact with the bottom, no messenger is required. The 6" x 6" jaw opening provides a 36 square inch sampling area.

Dredge Applications

A bottom sampling dredge consists of two halves of a relatively small box. The dredge is placed onto the bottom sediment, then closed and pulled up to retrieve a sample. A two-way mechanism prevents accidental closure while the dredge is dropping. The impact of the dredge on the bottom surface triggers the spring-loaded release mechanism without using a messenger. After mechanism closure, the dredge is pulled up to retrieve the sample.

Careful release of the sample distributes the sample approximately as it appeared on the bottom, making sediment profile description possible. The sample is not suitable for most geotechnical analysis and does not provide samples suitable for high-quality chemical analysis for volatile contaminants.