Last week, I said we’d discuss nautical design and maneuvering this week. I consider this important because one of the greatest innovations of the Early Bronze Age was the development of maritime commerce, interlinking many civilizations.
As I explained in blog 19, I needed ships in the fourth novel of my series. Having once been the General Superintendent of Shipbuilding at the Quincy MA shipyard, and an industrial engineer testing new attack subs at the Groton CT shipyard, I have some ideas about building ships – even in the Early Bronze Age. Here are my criteria for a ship design for the eastern Mediterranean 5,203 years ago.
(a) The purpose is to initiate trade relationships and suppress piracy along trade routes with a crew of 10, and transport 10 extra warriors or passengers when required.
(b) The ships must be able to run aground on beaches, and thus need a strong ramp-shaped bow and stout bottom to reach shallows for easy access.
(c) The draft should be no more than 3 or 4 feet, to allow wading ashore.
(d) Sole reliance on wind propulsion is risky, so the crew must be able to row to supplement the sail, add to maneuverability, and as sole propulsion in a calm. Rowers must sit below deck, rowing through ports.
(e) To offset the steering oar’s force and drag, and the number of steering oarsmen, a smaller aft lateen sail will be required.
(f) Sailing. To reduce the angle of attack at which the ship can sail into the wind, the ship will use a lateen mainsail, rather than a square sail which can’t sail upwind and is limited to reversing seasonal winds—making trips consume too much time to suit my story’s plot. Since there’s no evidence of the use of lateen sails in the Early Bronze Age, this is poetic license.
(g) To reduce leeway, allowing sailing closer to the intended line to speed up trips even more, starboard and port leeboards are required flanking the main mast. Leeway is an early problem in my novels, until bright minds put their heads together. This, too, is poetic license, since there is no evidence of leeboards more than 1,200 years ago.
2. Longevity: 10 years before major structural repairs and design upgrades.
3. Number: 100 ships built in each of 3 kings’ shipyards along the eastern Mediterranean coast, and in another kingdom in the northwestern Persian Gulf.
4. Production rate: One per month, per kingdom. Two kings already have 100 ships apiece, one has 80, and one is starting from scratch—getting a jump start by hijacking merchant ships in ports.
5. Availability of materials: Cedars of Lebanon (Cedrus libani) will supply eastern Mediterranean and Persian Gulf shipyards with planks and beams. Oak hardwood for fittings and leeboards was widely available in west Asia through the middle Holocene. Linen would be widely available for sails. Hemp rope would be widely available. Copper was available from Timna in useful quantities for shipbuilding tools such as drill points, saws, chisels, and hammer heads—but not for connectors.
6. Availability of skilled craftsmen: Archaeological evidence of mortise and tenon joints have been found in well linings dating back 7,000 years ago, and in very advanced form in the Khufu ship 4,500 years ago. This joint would be sufficient to bind planks to planks and frames, as would hardwood dowels allow the use of loose tenons. Copper drill points, saws, and chisels would greatly ease the tasks. Conveniently, the contemporary skills to mine, smelt, and work copper are evidenced by the Nahal Mishmar hoard of copper scepters, maces, and other implements found near the En Gedi Temple dating back 5,500 years.
You’ll recall my design from post 19:
Only a very rich king could build such ships on a large scale. However, every ship of this design would rapidly add to the owner’s wealth through pioneering maritime trade in this onetime opportunity in the Early Bronze Age. Innovators would be highly rewarded for opening up export markets and gaining access to raw materials and high-value merchandise. Those who started this maritime trading would gain a huge advantage over those who entered the trade later.
The last thing I will discuss is the maneuvering of this ship sailing into the wind. There are two ways to change the course of a lateen-rigged boat sailing with a wind coming over the port bow, so that it can sail with that same wind coming over the starboard bow: tacking and wearing.
Tacking is familiar to anyone who has sailed. However, after tacking a boat with a lateen sail (point A above), the sail will be in an inefficient “bad tack” (point B above) where the sail lays across the mast and interrupts the air flow, causing some loss of power. Here’s a picture of a boat in a “bad tack.”
This would be especially true in our design, because the main mast is closer to midships and more of the sail is collapsed by its leaning against the mast. Because so much power is lost on our designed boat, we choose the “wearing” option, which requires falling off from the wind and swinging the main spar vertical and, in this case, from the starboard side of the mast to the port. I have located the following picture showing this being done on a large sailing boat with a mizzen lateen sail at the stern—and help in raising the yard to the vertical is coming from the rope leading forward to (unseen) men on the main mast.
I’m sympathetic if you don’t understand the maneuver from this picture, as I worked hard to describe my characters doing this maneuver the first time in the 5th novel. I have never personally sailed in a lateen-rigged boat.
Well, so much for my design. Next week, we’ll study a few shipwrecks from the Middle and Late Bronze Ages that have been excavated by nautical archaeologist using scuba gear. And we’ll compare my design with those.
Thanks for visiting this week.