At work we have boats with anything from an 18 inch dome antenna
to a 4 foot open array antenna
. I have also used larger radars with previous jobs. Its not distance that a larger antenna will get you, its resolution. Most yacht radars have at least a 24 mile range although most yachts do not have a line of sight of 24 miles to the horizon. I also have an unlimited radar
endorsement (two contacts) on my license
For most yachts, you really don't need the narrower beam width. If there is something out there, it will just be a wider contact on the screen
and the difference in a degree or two between a wide beam or a narrow beam makes no difference in determining which course to take in order to avoid a collision
. Unless you are actually going to use your radar for determining a relatively accurate relative motion line (RML), it makes no difference.
As far as seeing land, it makes no difference. The land contacts will not be as clear, but they will still show just the same.
Sea Clutter, Rain Clutter or Gain has nothing to do with beam width. That's a completely different function.
Modern digital radars all have the ability to make manual adjustments or leave it in the automatic settings, which is fine for newbies. If you really want to tweak your radar though you need to manually adjust it.
For how yachts are used, it seems like a waste of money
to go with the higher resolution antenna.