PBR main propulsion jet pumps were easily damaged by ocean salt water which necessitated the boats being carried by another craft to their duty stations.

The pumping mechanism would then be reversed to clear the water out of the voids, restoring the craft to the normal floating position.

A fourth modification was the Army Version for Vietnam Rivers Logistic with a liveaboard cabin and crewed by six men consisting of Coxswain, Assist.

All crew could handle the two M2 Browning .50 caliber machine gun turrets and other small arms and were frequently engaged by the Vietcong on the rivers and canals of the Mekong Delta.

In I Corps (the northernmost military district in Vietnam) boats based at Da Nang, Tan My and Cửa Việt had three man crews of various rates and ranks.

The air cylinders were below deck in the eighth void from the bow and stretched cables attached to the ramp to raise it.

Some are currently deployed aboard Maritime Prepositioning ships to facilitate their mission of being able to unload all their cargo while still offshore with no outside assistance.

It also may be used in defended waters, being fitted with a subsurface surveillance device, protection from small arms fire, two Common Remotely Operated Weapon Stations, and mitigated detection through reduction of thermal and acoustic signature.

A fully functioning toilet (head) and shower are also installed as part of the wheelhouse extensions; external provision for bedding is also included for the full crew complement.

The extension of the wheelhouse increased rigidity of the craft leading to excessive vibration and cavitation with the original three-blade propeller.

The vessels are also installed with a full suite of electronics allowing the craft to navigate in all weather, day or night in military operations anywhere in the world with little to no special training requirements for an indefinite period.

Two craft were utilized during the invasion of Iraq in 2003, patrolling the shallow waters of the Khawr Abd Allah estuary using HMAS Kanimbla as their base of operations.