rib & hull

Lifeline

Time loop AU. When Keith wakes up after crashing his ship to stop Naxzela from exploding, he thinks it’s a dream. And then it happens again.

Some days he dies like this, closing his eyes to a light that burns him to the core. Other days, Keith dies with a knife between his ribs, or in the hull of a ship, or with the others as Naxzela renders the sky to pieces. Over and over and over. Again and again.

read on ao3 / ffnet / a lil thank u to @kcgane for making these tracks because. they’re good.

chapter one

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Ships (Part 1): Ancient Egypt

The oldest surviving depictions of boats are from the Nile Valley (rock carvings & pottery decorations), but they are from a relatively recent stage of ship development, about 6,000 years ago. We don’t really know much about the earliest history of boat-building, apart from looking at simple boats that are still used today – for example, rafts made of bound branches, used for rivers & lakes in some African countries; some South American peoples use hollowed-out tree-trunks for canoes, made using fire or simple tools.

The Nile Valley depictions generally show long, narrow boats, with a steering paddle over the stern (back), and men paddling amid-ships (in the middle of the ship).  These boats were usually made of papyrus reed, because suitable wood was scarce in this region. However, some of the boats are made of many short wooden planks, held together with pegs or rope binding.

Predynastic Egyptian vase, possibly 3200 BC.

The oldest surviving ship is the funeral ship of the Pharaoh Khufu (Cheops), who lived in the 2500’s BC.  He was the builder of the great pyramid of Giza, which was the first of the three Giza pyramids built by his dynasty.

His ship was made in prefabricated sections and then assembled.  It was buried in a great limestone pit on the Giza plateau, and covered over with 41 rock slabs, each one weighing about 18 tonnes.  She was buried there so that Khufu could take a voyage to heaven if he wished to.

Bow (front).

Stern (back).

She is a wooden ship (cedar imported from Phoenicia), made from 600 separate pieces of wood; and she is a lot bigger than any other ship of that time (40.5x7.9m), because she was built for the most powerful ruler of the time.  In fact, if someone had tried to sail her, she would have been broken apart by even medium waves.  What is important is the skill of the Egyptian shipwrights in working wood to make a ship’s hull (watertight body of a ship/boat).

A sort-of keel (underside) was built of timber.  A curved stern-piece and stem-piece were added, to the back & front of the ship. However, there were no ribs to fasten the hull planking to, and support the hull.  The hull planks are merely held in place partially by wooden pegs, and partially by small, shaped wooden blocks.

Around this time, Egyptian ships were trading in the Mediterranean with Crete and Syria.  We know this from stone reliefs and hieroglyphics, which also show that there was a war expedition to Phoenicia in 2700 BC.

The ships had one square sail, on a bipod (two-legged) mast.  The mast was stepped well forward into the ship.  This means that they could only use the sail in a following wind – one moving the same direction as the ship.  However, early pictures show ships with ropes attached to the yard (spar slung across the mast, for the sail to hang from).  This means that the yard could be braced round to the wind (to a certain extent) – i.e. to allow the ship to sail at a different angle to the wind.

Like Khufu’s funerary ship, they had not ribs (rising from the keel) to support the outside hull planking.  They had no deck beams to maintain the upper hull shape.

Lengthways (longitudinal) support was provided by a long rope stretching from stem to stern.  It was given tension by a bar of wood.

Widthways (athwartship) support was provided by winding two ropes tightly around the upper hull.  They were given tension by “a series of zig-zag racking turns with a smaller rope”.

Previously paddlers had propelled the ship, but now rowers were used. This is because the Egyptians had discovered how to attach the oar to the gunwale (upper edge), and use it as a powerful lever.

Paddles propel a ship the direction the paddlers are facing; oars propel the ship the opposite direction (backwards).  Paddles are not attached to anything, whereas oars are.

A modern drawing of an Egyptian ship from 2700 BC.

2600 BC.

A millennium later, the rock temple at Deir el-Bahri (Thebes) has a long series of reliefs, depicting Queen Hatshepsut’s expedition to the land of Punt.  She took 5 ships, and they were searching exotic goods such as monkeys, greyhounds, myrrh and ivory.  Hatshepsut was the co-regent & sister of Pharaoh Thotmes II.  The date given on the reliefs is 1500 BC.

Punt was in NE-Africa (probably), further south than Egypt.  It would have been a long journey, down the Red Sea and around the Horn of Africa, so the ships obviously had to be larger, with larger crews.  The ships in the reliefs are about 30m long, with 15 rowers per side (30 total).  They have a single square sail on a yard.

The mast is now stepped amidships (in the middle), not forward.  So the yard could now be braced to a beam wind (right angle to the keel), not just a following wind.

Also, there is a row of deck beams carried through the hull planking (side-to-side). These gave athwartships stiffness, required for a ship to sail in anything but the calmest waters.

The rope giving longitudinal stiffness is still there.  The mast is now in the middle of the ship.

The temple reliefs also show another Egyptian ship, built specially for transporting obelisks.  Obelisks were hewn straight from the granite at Assuan, and transported on these ships down the Nile to Luxor.  They were about 29m high, and weighed about 350 tonnes

According to a court official at Thotmes, the obelisk ships were about 55m long, with a beam (width) about 18.3m.  However, they would probably have to be larger to not sink under the obelisks’ weight – possibly 61x23m.  The ships carried two obelisks each.

Obelisk transportation relief.

By 1500 BC, Egyptian ships were very much like modern ships in their basic design.  The long, central keel had been developed; shaped stem & stern pieces were attached to each end; and deck beams now supported the hull.  All that was missing were the ribs, rising from the keel and shaped to support the hull planking.