Shipworms

Overview

Shipworms are not worms but molluscs, kin to the clams, that live inside wood in the sea. They bore through the hulls of craft, the piles of quays, the timber of breakwater works, and any driftwood, and they do it from the inside, so that a pile can look sound and be hollow. On the Tidelace Coasts and along the Soundchain Roads they are the breakwater crews' other enemy, after the storms.

Appearance

A shipworm is a soft, pale grey-white tube of a body, as long as a finger or a forearm and no thicker than a reed stem, with a pair of tiny, ridged, white shells at the head end like the bit of an auger, and at the tail end two short siphons and two small hard plates that close the tunnel. It is never seen alive outside its wood. What people see is the timber: a piece of sea-soaked plank or pile that, split open, is riddled with tunnels as thick as a finger, lined with chalky white shell, running along the grain. The tunnels' mouths on the surface are pinholes. Rotten shipworm timber smells of the sea and old cheese.

Habitat and Range

They live in any wood that stays in salt water: the hulls of craft, quay piles and mooring posts, the timber of old breakwaters, wrecks, and drift. They need full salt water and grow fastest in warm summer seas, and they are fewer in the brackish estuaries of the Tidebound Reaches. They are found the length of the coast.

Behaviour and Temperament

A young shipworm settles on wood as a speck, drills in through a pinhole, and spends the rest of its life boring along the grain, eating the wood dust and filtering the water drawn in through its siphons. It never comes out. Many in one timber honeycomb it, never breaking into each other's tunnels, until the wood fails.

Life Cycle

Shipworms spawn in summer; the young drift for some weeks and settle on whatever wood they find. They grow fast and live a year or two, by which time a summer's settlement can have hollowed a new pile.

Uses and Dangers

They cost the harbour towns dearly. A quay pile can fail without warning under a loaded cart, and a hull that looks sound can open in a swell. Craft are hauled out every year, scraped, burned, and tarred, and the best hulls are sheathed in thin plank laid over tarred hair; quay piles are inspected and replaced on fixed rounds by the breakwater crews, and the sounding houses keep a ledger of every pile's age. Gnome harbours build their breakwaters in stone for this reason as much as for the storms. Coastal Human hamlets draw their boats up on the shingle and dry them, which the shipworms cannot survive. Some fishers eat them, raw, from split drift timber.

Lore and Belief

Breakwater crews say a shipworm is a careless mark in wood: it looks true until the weight comes on it. A harbour family's honesty is measured in its readings, and a crew that lets a pile go unchecked has done a dishonest thing in the crews' eyes even if no one is hurt. Human fishers say a hull a shipworm will not touch has been blessed by Maris.

Wreckers are said to know which hulls the worm has eaten and to lure those ships first, since a riddled ship breaks up fast on the rocks and spills its cargo onto the shingle.

Where It Appears

• Overview: Animals