What is a Watermaker?

A Watermaker or Water Maker is nothing more that a Reverse Osmosis System
, Wikipedia defines Reverse
Osmosis as:

Reverse osmosis (RO) is a water purification technology that uses a semipermeable membrane to remove
ions, molecules, and larger particles from drinking water. In reverse osmosis, an applied pressure is used to
overcome osmotic pressure, a colligative property, that is driven by chemical potential differences of the
solvent, a thermodynamic parameter. Reverse osmosis can remove many types of dissolved and
suspended species from water, including bacteria, and is used in both industrial processes and the
production of potable water. The result is that the solute is retained on the pressurized side of the
membrane and the pure solvent is allowed to pass to the other side. To be "selective", this membrane
should not allow large molecules or ions through the pores (holes), but should allow smaller components of
the solution (such as solvent molecules) to pass freely.

In the normal osmosis process, the solvent naturally moves from an area of low solute concentration (high
water potential), through a membrane, to an area of high solute concentration (low water potential). The
driving force for the movement of the solvent is the reduction in the free energy of the system when the
difference in solvent concentration on either side of a membrane is reduced, generating osmotic pressure
due to the solvent moving into the more concentrated solution. Applying an external pressure to reverse the
natural flow of pure solvent, thus, is reverse osmosis. The process is similar to other membrane technology
applications. However, key differences are found between reverse osmosis and filtration. The predominant
removal mechanism in membrane filtration is straining, or size exclusion, so the process can theoretically
achieve perfect efficiency regardless of parameters such as the solution's pressure and concentration.
Reverse osmosis also involves diffusion, making the process dependent on pressure, flow rate, and other
conditions.[1] Reverse osmosis is most commonly known for its use in drinking water purification from
seawater, removing the salt and other effluent materials from the water molecules.

The marine industry has named the Reverse Osmosis Systems Found in Yachts as Water Makers and it is
very common to use the term spelled in one word "Watermaker".  The units found in Yachts and Vessels
are no different in operation to those found in the Residential, Commercial and Industrial applications.
Except for some cosmetic adaptations, must components are the same as all of those other systems.
Reverse Osmosis Membrane