Watertube

Watertube was a Fremen device of wide application in the transfer of liquids.

Watertubes existed since the final stage of the Zensunni migrations. Its sophisticated design is an example of the Fremen attention to minute detail. The close investigation prompted by scattered comments in the Dunebook, revealed sophisticated attention to details of watertube design and manufacture behind its simplistic appearsance, which in turn confirms the extraordinary importance of water conservation in the desert environment of Arrakis

Usage
The watertube was used anywhere that liquids, especially distilled water, had to be transferred since it conserved moisture, especially that given off by the human body, crucial to survival on Arrakis. They were used in stillsuits between catch-pockets and mouth, and even between bodily orifices and processing catches. Tubes were built into the catchpockets of stilltents. The Huanui (or Deathstill) used watertubing in the drainway and between the waiting basin and the flowmeter. Watertubes were also used in literjons, flowmeter spouts, and portable windtraps.

Construction and function
The compound used for the body of the tube was melange-based plastic with plyotyl mixed in to provide the needed flexibility. The plastic was liquified and forced into a mold of plasteel, usually 10 to 15 cm square and 2 m long. The mold consisted of a group of holes of different diameters. A cap at one end allowed extrusion of rods as long as the mold and of varying diameters. The cap at the far end of the mold received the rods and thus helped maintain consistent thickness of the watertube being formed.

A half dozen of the molds were discovered at two sites on Rakis which led scholars to speculation that tube walls could be varied in thickness depending on which way the caps were put on the mold. No matter how the caps were installed, the rods would penetrate the match-up holes. But when the caps were rotated a quarter turn, the relation of rod size to mold-hole diameter changed. The result could have been that different production needs for watertubes of different flexibility and inside diameter were taken care of by a small number of multi-purpose mold-and-cap combinations.

However there were no finds to confirm this or the possibility that switching caps among molds could have given-the Fremen almost infinite varieties of characteristics. Some analysts say that these speculations overlook the Fremen characteristic of keeping technology simple; others say that this kind of flexibility and adaptability would reflect their sophistication.

The findings also show extraordinary uniformity of dimension, suggesting that some supplemental mechanism must have been used to keep the rods perfectly straight inside the mold holes. The most common theory was that ultrasonic radiation, applied to the cooling plastic/plyotyl in the mold, contributed to stabilization of the fluid and thus to macroscopic uniformity of tube wall.

Partially cooled tubes were removed from the molds and passed through the bonding vat where the still-tacky inner surfaces, but not the cooler outsides, collected the crystalline solution which formed, as it "dried" and bonded to the plastic tube, the friction release coating. Finally, the active processes completed, the watertubes, now looking like thin, limp cords of slightly different diameters, were taken to drying racks where they "set up" and cured.

The Dunebook referred to the nearly frictionless surface of equipment associated with water measurement, suggesting a "crystalline solution" and clarifies the function of the "bonding vat". Some relics revealed trace samples of a flexible crystal that is almost inert at normal temperatures. Significant amounts of the substance have been found only in the vicinity of some "bonding vats." Peri/pherometric analysis indicates that the Fremen's frictionless material has an intramolecular structure close to later Pethlax and the prototype Frolmyr compound.