There was danger of receiving some monstrous surge aft.

Those mountains of water ran faster than the schooner, threatening to strike her stern if she did not rise pretty fast.

That is extreme danger for every ship which scuds before the tempest.

But what could be done to ward off that contingency?
Greater speed could not be imparted to the "Pilgrim," because she would not have kept the smallest piece of canvas.

She must then be managed as much as possible by means of the helm, whose action was often powerless.
Dick Sand no longer left the helm.