The VibeCore-D can take 2” or 3” diameter core samples and the new VibeCore-4D adds the ability to take a 4” diameter core sample. The SDI VibeCore can operate at up to 120 foot water depths and takes up to a 20 foot long core tube.
“Operating water depth” – The VibeCore is effective from virtually no water depth to about 100 feet or up to 200 feet if the deep water option is selected. The vibrating head goes underwater so there is no need for longer core tube than the sediment sample needed. Other systems you may be familiar with clamp onto the side of a core tube and the coring head needs to stay above water. This is not the case for the VibeCore.
“Core sample length” – We have taken 18 foot long samples with a 20 foot core tube on the VibeCore. We reached the point of refusal at about 18.5 ft. The VibeCore will reach refusal if it encounters large gravel, a root, rock or sediment with very low water content. Generally we find we reach refusal in man made lakes a few inches into the pre-impoundment material as the pre-impoundment material water content drops below 10 to 15% and has rocks and debris not usually transported a significant distance from the edge of a reservoir after impoundment.
“Core compression” – Another factor in core sampling is “core compression” This “core compression” term is a bit of a misnomer. Water is virtually incompressible and usually even less compressible when dealing with water saturated sediments. The core material does not compress. A more accurate description is that the material fails to enter the core tube.
Read the “Vibecore Application Note”