Sometime before 1965 (probably 1958-63) I read a YA hardcover book that I've since been unable to track down.
I have a memory of the cover showing a boy/young man (maybe more than one) on land (maybe a cliff) overlooking a bay on the ocean and two (or maybe three) waterspouts rising up in the bay.
The story is about the kid who gets involved for some reason with a scientist in a hidden lab in Western US who has developed some sort of gravity control apparatus. For some reason they need to test it on the opposite side of the Earth from the generator and travel to (I think) Kerguelen Island in the south Indian Ocean to do it. I think it's there that they see the cover scene of a line of waterspouts marching across the bay as a reversed gravity beam comes through the Earth.
There are bad guys and adventure as the good guys (including the kid(s)) prevent the machine from falling into the wrong hands (or) recover it after it has.
For years I was convinced that this was a Winston Juvenile (similar format, similar reading level), but I believe that I have seen them all and none of them come even close.
I don't remember the story as being especially great, but it's one of the very few things I've never been able to track down.