The Cardenas is a small dinghy used by the PLAV to patrol the shores around their outposts. They can easily be found patrolling the lake around the PLAV HQ and can also easily be found around the Orinoco River Outpost, both on patrol and docked. The Cardenas seems to be stolen from UP due to the fact that the Cardenas is almost exactly the same as the UP Inflatable, the only major differences being the mounted weapon, the color scheme, which is green with what looks like a snake face painted on the front, and the camo net on it.
Aside from the various civilian boats such as the Trawler and the motorboat, this is one of the most useless boats in the game. It is very slow, and leaves the driver open to fire from all sides. The weapon in the front has a very small aiming radius, and the boat itself is hard to turn and has a very large turn radius. You would be much better suited to buy and use the Wave Skimmer, sold by the Pirates for the same price, which is much faster.
The Inflatable is based on the inflatable boats made and popularized by the Zodiac Group.