What is "redoubles"

Usage examples of "redoubles".

The moment after a ship has passed over the smooth surface, the sea redoubles its violence, and woe to the bark that follows.

But so much the more her anger increases, and she redoubles her efforts, like the craftsman who sees his work unfinished while the day is wellnigh spent.

It’s insanity, he wants to crush her, a little gauge inside his ribs doubles and redoubles his need for pressure, just pure pressure, there is no love in it, love that glances and glides along the skin, he is unconscious of their skins, it is her heart he wants to grind into his own, to comfort her completely.