No the folks in Placencia did something very well studied and ecological - I think they used logs actually. It was a really cool thing. I guess my point is that the groins tend to work, but you might need a permit to keep one. I've seen some subtle ones in play along the shore here - boulders under piers ....... they attract fish, hold sand, and are not "construction" in a way that excites people into court.
Indeed the beach on either side of the groyne grew - one more significantly than the other, but both benefitted.