I have EXACTLY that set, and its exactly same as turborix and flysky etc as mentioned previously, I have them also.
I sail 4 models with one tx, you only need to change on a pc because they do not have compterised model memory in the tx, so you set it up on a pc, and save that folder, for example as boat 1. THe trick is to have all your boats with the same settings, eg rudder direction etc, then you do not need to change the settings at the lake with a laptop, just turn on each boat at different times

Multiple receivers are cheap, but there is version 1 and version 2, and they cannot be inter changed, so be careful if buying old stock or second hand. The general rule is version 1 receivers have very long antennas, version 2 are short.
They are pretty cheap, and "plastically", with the batteries in the weight is ok, buit with 1.2v rechargeable batteries the volts drop pretty quick and range diminishes, I fitted two extra batteries inside the tx to boost the volts back to same as standard 1.5v aa batteries, and the range increased dramatically. One of mine is a 6 channel set, its fab for lights, monitors etc as two of the channels are proportional by virtue of proportional knobs
