I don't really care when people say stuff like "Dick Dale was the godfather of Heavy Metal". Surf music, as far I can tell, is when rock & roll musicians really started to embrace loudness and aggression. It's not a stepping stone to other loud forms of music, it's the dawn, and whatever came afterwards simply came later. And part of why I say this is because just as metal, etc can take influence from surf, surf can grab back too. This is the category for bands that focus on that aggressive sound.