21 Riverine

Typical Specifications

LOA: 21
BOA: 8

For detailed specifications, contact us today.

The Metal Shark 21 Riverine is a rugged and reliable shallow-draft patrol boat specially designed to withstand harsh operating conditions. The vessel is a smaller version of the 24 Riverine produced by Metal Shark for US Department of Defense CNTPO contract customers and currently deployed to multinational forces in Latin America on border patrol and counter narco-terrorism missions. The 21 Riverine is shown here is a test platform equipped with the innovative Swamp Shark surface-piercing all-terrain drive, which allows the vessel to traverse shallow waters, loose mud, dense vegetation, and debris-strewn waters.

Hull Design

The 21 Riverine features a proven hull that has been designed and built for shallow water operation and optimized for impact resistance. The vessel features fully welded aluminum construction and heavy duty ¼” bottom plating to provide the heft to withstand harsh operating conditions and impacts with submerged debris. Equipped as shown with a 270 HP turbo diesel and Swamp Shark surface drive with closed cooling, the 21 Riverine is operational in extreme shallows of just a few inches of water, or even loose mud. Click here to see additional Swamp Shark test footage.

Deck Layout

The 21 Riverine is shown here in a basic configuration for testing. Like all Metal Sharks, the 21 Riverine may be fully customized to meet various mission requirements. The vessel can accommodate a crew of six with a double-wide helm seat, forward console seat, and two flip-down seats forward. The vessel shown here features a basic console. The 21 Riverine may be equipped with a full console with full-height windshield, and a dual purpose canopy that provides weather protection as well as secure aft-deck hand-holds. An integrated forward boarding step allows for quick, surefooted access during landing operations. Low-level LED lighting discretely illuminates walkways. A full-width transom swim platform allows for easy self-recovery with a ladder that stows securely when not in use. The 21 Riverine may be configured with multiple gun mounts as required.


The 21 Riverine shown here and in the video above is a powered by the Metal Shark-exclusive Swamp Shark all-terrain propulsion system, which has been specially engineered and built for operation in extreme shallow water, riverine, and mud flat environments.

The highly durable system will safely and reliably propel the 21 Riverine through dense vegetation, mud, and debris-strewn waters. Swamp Shark’s specially-designed outdrive features hydraulic power trim and steering, and its stainless steel surface-piercing propeller easily powers through mats of vegetation, bushes, or branches, while offering outstanding control on open water even at high speed.

A patented hydraulic / electric rebound system, which consists of actuators inside and outside of the vessel, allows the drive to smoothly and automatically adapt to conditions. When the drive impacts a solid object, such as a log, stump, or other submerged hazard, it swiftly “kicks up” so that the propeller will not be impacted. The system then exerts reverse pressure to instantaneously return the drive to its normal trim position as soon as the object has been cleared.

Swamp Shark features a fully self-contained, patent-pending, onboard keel cooling system, with no appendages beneath the hull and no need for overboard raw water. This allows for smooth operation over underwater obstacles and allows a Swamp Shark-propelled vessel to traverse shallow, vegetation-clogged water or even loose mud with no cooling issues. The highly-efficient system cools engine oil, power steering and transmission fluid, and also boost-air intercoolers for turbo or supercharged engines, all with no reliance on outside water.



Equipped as shown with a 270-HP turbo diesel with 575-Ft.-Lbs of torque and Metal Shark’s military-exclusive Swamp Shark surface drive, the 21 Riverine reaches 50-knot top speeds while offering shallow-water, swamp, and mud-flat capabilities unmatched by any other propulsion system. The 21 Riverine can safely drive across logs or other solid obstructions at a high rate of speed, and thanks to its closed cooling system with no appendages, the vessel will never suffer from overheating due to clogged intakes. Swamp Shark is the most durable and innovative shallow-water propulsion system on the market today, and it’s only available to military and government users through Metal Shark.

For more information about this or any other Metal Shark model, contact us today.