An amphibious excavator is a standard excavator fitted with a floating undercarriage, which lets it work directly in wetlands, shallow water and soft banks that a wheeled or tracked machine could never enter. Below, we explain how the Bell Amphibious Undercarriage gives an excavator this floating capability, and how the Bell Amphibious Excavator range compares by tonnage class.
The Bell Amphibious Undercarriage, or BAU, is what turns a standard excavator into an amphibious excavator. Instead of the machine’s usual tracks, it sits on a set of floating pontoons that carry its full weight while it works, so it can move and dig in wetlands, shallow water, mud and soft banks that would swallow a normal excavator.
The undercarriage itself does the work: the pontoons provide buoyancy, and side pontoons with spud legs give the machine stability and anchoring, even on an underwater slope. On top, the excavator’s cab and boom operate exactly as they would on solid ground, so operators do not need to learn a new machine, only how to work on water.
An amphibious excavator needs to do more than float. Three features are what make the Bell Amphibious Undercarriage practical on a real worksite.
The ERN version (Extendable, Retractable, Narrow) lets the side pontoons hydraulically slide in and out. Retracted, the machine fits within standard transport width, so it can be moved between sites without being partly disassembled. Extended, it gets the wider stance needed for stability while working.
Spud legs mounted on the side pontoons anchor the machine in place, which matters when working on an underwater slope or in current, where a floating machine could otherwise drift or tip.
The Bell Thruster adds powered propulsion, so the machine can maneuver itself across open water or against a current instead of needing to be pulled or pushed into position.
Bell fits the BAU undercarriage to excavators ranging from the BAU35, matched to 3-5 ton class machines, up to the BAU400 for the 40-45 ton class. Each undercarriage size is matched to the excavator’s weight, float capacity and digging depth, so the pairing keeps the machine stable at its working boom length rather than being an afterthought bolted onto an existing excavator.
Heavy duty long reach arms are also available across the range, developed specifically for use with a Bell dredge pump, for projects that combine excavating and dredging in the same operation.
The Bell Swap System lets an excavator switch between its standard undercarriage and the amphibious version in around 30 minutes. That matters for fleets that need the same machine to work on land one week and in wetland or shallow water conditions the next, without owning two separate excavators.
Because the swap is fast and does not require specialist tools, an amphibious excavator fitted with the BAU undercarriage can move between conventional earthmoving work and amphibious dredging or vegetation clearing jobs as the project demands.
Our amphibious excavators are built in-house across tonnage classes from 3 to 45 tons, with the ERN undercarriage, Bell Thruster and Swap System available depending on the model. Have a look at the full Bell Amphibious Excavator range, or contact us to discuss which tonnage class and configuration fits your site.
