As long as you are on a fixed non-moving location the installation of a satellite antenna dish is pretty straightforward. You point the satellite dish to the desired satellite and your decoder does the rest. As geo-stationary satellites are always in the same location you do not have to change the direction your satellite dish is pointing to unless you want to aim it at another satellite (with eventually different channels).
At sea this becomes a more difficult situation because your ship (be it big or small) is traveling from one location to another and also it moves because of the waves it is floating on. To be able to receive a continuous TV signal you will have to have an antenna that automatically points towards the right satellite and corrects itself with every little movement of the ship.
These specific antennas are called Maritime Stabilized and provide a permanent tracking of the satellite of your choice. Satmarin offers a wide range of maritime stabilized satellite TV antennas for every need and every budget from Seatel, KNS, Intellian and Orbit.
Signal strength varies depending on the location you are. In satellite terms this is called a footprint. Every Satellite (with its different beams, has different footprints and will only cover those regions which fall within its footprint. Below you'll see an example of a footprint of an Astra satellite at 19.2°E
The footprint signal is strongest in the center and becomes weaker as you move to the outside of the footprint. If the area you are in is at the edge of the footprint then you will need a larger satellite antenna to receive enough signal strength so that your decoder can convert the received digital signal to a crisp image and high quality sound. You will notice the edge indicates the different minimum dish sizes needed to receive this satellite's signal correctly.
Not all antennas are of the same quality! Depending on the manufacturer of the antenna they will have created a satellite antenna with high quality reception or not. To compare the different antenna qualities you will need to check the antenna's minimum EIRP (Equivalent Isotropic Radiated Power). The lower the minimum EIRP of the antenna is, the better the signal strength received by your antenna will be.