Seagoing sailing ships

Seagoing wooden ships are built frame first: the keel, then the stem and sternpost, then frames set across the keel close together, then carvel planking laid edge to edge and fastened to every frame it crosses with trenails (wooden pegs) or iron, and the seams caulked with oakum and pitch. A keelson over the frames locks them to the keel; deck beams and knees tie the sides together. The ship is steered by a rudder hung on the sternpost and turned by a tiller, or on a big ship by a wheel through ropes.

Smaller hulls can still be built shell-first, planks before frames, as in plank boats.

• Square sails hang from yards across the masts. They are powerful with the wind behind and on the quarter, and make about 60° to the wind at best (Queen Anne's Revenge Project).
• Fore-and-aft sails (lateen, gaff, and the modern triangular sail) lie along the ship and work to about 45°.
• To go upwind, tack: sail close-hauled on one side of the wind, then the other. Ignoring leeway, gaining 10 km straight upwind takes about 14 km of sailing at 45°, and 20 km at 60°.
• Most ships carry both: square sails for the long runs, fore-and-aft sails to point higher and to steer by.
• A lee shore — coast downwind of the ship — is the square-rigger's worst danger: if it cannot point high enough to claw off, it is driven ashore. Keep sea room.

Before the Vasa sailed, thirty men ran back and forth across its upper deck to make it roll; after a few runs it heeled so far that they stopped, for fear it would capsize at the quay. It sailed on 10 August 1628, heeled over in a gust about 20 minutes later, took water through its open lower gun ports, and sank; about 30 people died (Vasa Museum).

• Ballast low, weight low, guns and cargo as low as they will go.
• Lower openings shut at sea: gun ports, cargo ports, hatches.
• The test is the ship's, not the schedule's. A ship that fails does not sail until it passes.
• The standard test today is the inclining experiment: a known weight is moved across the deck, the heel measured, and the ship's centre of gravity calculated from it.

A wooden ship always leaks a little. Sound the well — measure the water in the bilge with a rod on a line — every watch, and pump it dry. A sudden rise means a sprung plank or an opened seam: find it, and caulk or patch it from inside. Keep the decks and topsides wet in hot weather, or the seams open. Carry spare oakum, pitch, sheet lead and nails for patching.

People who get less than about 10 mg of vitamin C a day for many weeks get scurvy (NIH): tiredness first, then bleeding gums, bruising, slow-healing wounds and death.

• One orange holds about 70 mg (NIH): a week's minimum.
• Sources that keep at sea: citrus fruit or its juice, potatoes, sauerkraut, and grains or pulses sprouted aboard.
• Heat and long storage destroy vitamin C: do not boil it, and do not trust an old store.
• The Royal Navy issued lemon juice to every sailor every day from 1795, and scurvy had nearly gone from its ships by 1797 (James Lind Library). See nutrition.

Latitude from the Pole Star or the noon sun, direction from a compass, and dead reckoning — course, speed and time, written in the log every watch — are in the navigation guide. Sound the depth with a lead line near land, and keep a chart of what you find.