Underwater Vibracorer

Rocky Mountain Soil Sampling uses a Rossfelder Underwater Electrical Vibracorer. Working from Plan B, this system can be used in water over 100 feet deep to collect continuous core samples.

Cores barrels are three- or four-inch diameter and can be up to twenty feet long depending on your application. Several choices in core barrel materials are available including Stainless Steel and Aluminum as well as clear plastic core liners.

The Rocky Mountain Vibracorer uses Contra-rotating Dual-eccentrics and High-frequency vibrations of 8,000 VPM and is ideally suited for sampling the unconsolidated sediments of a marine environment. Power is from a small generator with waterproof cables and extraction by means of a small winch or crane system.

When using Commercial Divers to collect underwater cores, they usually require a three-man team. Divers have obvious physical limits and can only take limited samples usually by hammering a core tube into the bottom. Doing this underwater can be quite a challenge at the best of times. Besides being potentially quite expensive for this set-up, samples can suffer from what is called a ‘Rodding Effect’. This is where wall friction inside the tube exceeds the bearing strength of the sediment layer you are sampling, causing sample recovery to be limited at best until a harder layer is encountered below.

Another popular method is a clamshell ‘Ponar’ sampler. It is lowered to the seafloor and takes a scoop of the bottom using its own weight, then is pulled back to the surface. This is a great way to see what the composition of the seafloor is, but penetration is limited to about a foot deep.

One last method for drilling on the water is mounting a drill rig on a barge and drilling with Hollow-stem augers and split-spoon samplers through the middle. As well as the high cost of the barge and support boat rental, depths are limited to 30-feet or so depending on your location and water conditions.

We feel our Vibracoring system is one of the best methods of underwater coring available and we look forward to using it on your next project.