Water Tank Sled

It is commonly known that a group staying in one place for prolonged period of time on The Surface is a bad idea. No matter the precautions, for some reason it attracts the ever-hungry Beasts from Above. Even the oases aren't safe from that and no one wants to risk being the one who was the reason why the only point of relief in the radius of kilometers got destroyed. That's why, because tribes need to constantly move, water tanks sleds were created.
Driven by independent groups, water tank sleds drive between two or more oases, collecting water and delivering it to anyone they encounter on the way or contact by radio.

Construction

If one would like to categorize the WTSes, due to the technologies used in their production, they can be classified as "children" of the Sandboards.
All water tank sleds are almost completely made out of Beast parts to prevent as much possible damage coming from the sun, especially its corrosive properties. Once in a while, the protective oils that cover them still need to be reapplied and so the crews driving them will happily take those oils as payment for delivering the water.

To increase the capacity of a water tank sled the crews attach gas bladders to their vehicles. These organs are filled with gas which reduces the weight of anything it is attached to.
To give the sleds an ability to move forward, even uphill, the webbed legs of the Beasts need to be used as sails as for some reason, they tend to tense up as if there was a wind pushing them. Even if there's almost no wind in The Surface.
Various other parts, such as carapaces, are used both as the bottom of the sleds and the containers for the water.

Armor and defense

Anyone with a grain of common sense knows to not attack the vehicle but the crew. Because of that, the crews driving WTSes come heavily armed with both armor and Spearguns, ready to fight off anyone stupid enough to disrupt their deliveries.

Communication Tools & Systems

Most of the water tank sleds are equipped with either radiostations or walkie-talkies to communicate with anyone on their route (or slightly off-route) who'd need their services.

Nickname

WTS, Water Relief, Water boys (mostly a name for the crew)

Price

Most of the crews built their sleds by themselves and rarely ever sell them, the price can greatly vary depending on the size of the sled.

Beam

Up to 4 meters.

Length

Between 2 and 10 meters.

Height

Up to 4 meters.

Speed

15-20 km/h. The fastest models can reach up to 30 km/h

Complement / Crew

Between 1 person in smallest models to 5 in the bigger ones. If the sleds form a caravan that number grows.

Cargo & Passenger Capacity

Smallest can carry 80-liter cylinders and a driver, the biggest ones that have been upgraded with gas bladders can carry up to 160,000 liters of water and a 5 person crew.