In The Coming of the Whirlpool Dow Amber first learns of the substance called nicre, a thin shell that forms on the wooden hulls of boats and ships in seawater (but not in fresh water) and which can protect those hulls almost indefinitely from rot and barnacles. It is understood by Ship Kings scholars that the smooth lining is formed by tiny organisms in the seawater that bond with the wood; these organisms are also called nicre.
However, these nicre have a far greater effect upon the world of the Four Isles than merely the preservation of wooden hulls—as Dow will learn in the later volumes of the Ship Kings series. Indeed, although invisible to the naked eye, the microscopic organisms are so influential that they turn the Great Ocean into something quite different from our own seas.
In warmer regions, for instance, the nicre organisms multiply a hundred fold so that seawater becomes heavy and thick with them, preventing evaporation. It’s this effect which creates the famous Barrier Doldrums and which dooms any attempt to sail to the southern hemisphere. The Barrier Doldrums are far worse than the equatorial doldrums of our own ocean—they are a vast lifeless region of flat, syrupy seas and parched air, devoid of all wind or weather, and are death to any sailing ship. Also, perilous creatures stalk there.
Likewise, nicre effect the colder arctic waters. In freezing temperatures, the organisms create a strange capillary action in the seawater, so that once sea ice begins to form, it rises higher and higher, resulting in icesheets and icebergs of spectacular size and tottering instability—the dreaded Unquiet Ice, into which Dow will voyage in Book Two of the series.
It’s only in the mid-latitudes with milder temperatures that the nicre have little obvious effect on seawater, other than bonding with wooden hulls, and so it’s only there that we find an ocean similar to our own, one that is safe for regular voyaging. It is a fortunate chance then for the Ship Kings mariners that each of the Four Isles lies in such latitudes.
To the folk of New Island, long denied by their Ship Kings overlords the right to sail the seas, the words binnacle and compass were unknown, and the art of navigation was a mysterious secret. All they knew for certain was that on every Ship Kings vessel there was a strangely shaped stand set in front of the ship’s wheel, and within that stand was held a device that somehow enabled the Ship Kings to find their way unerringly across the ocean, even when out of sight of land or beneath an overcast sky. What the device was exactly, or how it worked, no one could say. Indeed, many New Islanders became convinced that it must be a matter of some dark magic.
For the Ship Kings themselves, of course, there was no such mystery. The stand was called a binnacle, and the device it held within was a compass. The binnacle’s purpose was to protect the delicate compass from wave and weather under a window of glass, and it was set in front of the wheel so that it would always be visible to the steersmen as they held the ship to its course; at night it was illuminated by oil lamps. The strange metal knobs that protruded from the binnacle and gave it such an odd appearance were simply there to help balance the compass needle against the pull of the iron within the rest of the ship—the cannon, for instance, in the Chloe’s case.
There was no magic involved—other than that of magnetism itself. Nevertheless, the Ship Kings saw fit to forbid such knowledge from all their subject peoples, under penalty of the lash. Dow Amber was the first New Islander in generations to dare to break that ban and to gaze upon a compass dial. Alas, he was caught, and a terrible punishment ensued. And in any case he learned little from that first glimpse, for as he would later discover there is far more to navigation than merely knowing which way is north.