I stay steer clear from Elco's. They don't pack a punch, true, but I definitely don't want to lose anyone because of them. Even if you do take one out, more will spawn, they will be rather annoyed what you did to their mates and they always report your location to their big brothers= destroyers and such. Since they operate at coastal waters, waters there tend to be on the shallow side. So, I just avoid them like plague. But yes, it sure is nice to bag one if it goes to that
My way of dealing with them? 37mm, accept no substitutes.