Current Rider

The current rider is a small boat, or perhaps more of a large board, used by river elves as a personal water vehicle. They typically only hold one person, though a dual-person variant does exist. Their speed is largely dependent on the currents on the water their used in, which makes them most effective as a means of transport in faster moving sections of rivers, though their construction does allows for some motion created by the shifting balance of the rider.
While many elves prefer to simply use small boats to get around the river, current riders have a growing level of popularity, particularly among adolescents. There are even certain sports designed to be played atop them that are steadily growing in popularity among river elven youth.
They've also been adopted for combat use, though not by every village and typically only by a small subset of a settlement's troops. Some of the most skilled among them however has proved to be a very valuable asset given the speed and maneuverability they have on a terrain that doesn't befit many of their attackers.

The Riverwatch

In particular, a skilled group of elves known as the Riverwatch patrol along the river from time to time atop current riders, keeping fishing boats and smaller transports safe from goblins and other threats they may face out on the river. They are among the most skilled users of the current riders, and move with a speed and grace not often possible on either land nor sea. This has earned them a fiarly notable amount of fame, and many an excitable river elf youth aspires to join their watch.

Propulsion

Primarily generated by the current of the water, though the construction of the boards allows the rider to shift their weight and the angle of the board to move in different directions using the various slants on the bottom of the board. Some newer version use different types of wood or different treatments on different parts as well, affecting the buoyancy and other factors of the wood. This makes the boards more difficult to ride as it affects their balance, but it also gives the rider greater control if properly used.