I hope that the large open array radars on ships are better than the small radome on my boat. Small vessels, even small metal vessels, do not have a strong return if there is any appreciable sea running. I have no confidence at all that I would spot a small boat on radar in bad conditions prior to running them down. Oh I would probably see some of them, maybe most of them. Large ships are much better, but even then in heavy rain they are invisible.

The many tests of radar visibility of small boats confirms this. If you want to be seen you need all the help you can get. And even then, don't assume you will be seen.