Marsh Buggies, Inc. - Manufacturers of amphibious equipment designed to work through mud, swampland and other harsh terrains. Products include buggies, excavators and draglines.
Normrock - Manufactures amphibious machinery for dredging and aquatic excavation. [French/English/Spanish]
The Rotech Group - Manufactures dredging tools that use the mass flow propeller technique to effectively excavate non-cohesive, unconsolidated, granular material.