Sunday, August 23, 2015
Oars at War, XII Century
La Nave Vale Cento
Galleys, Dromons, and Triremes are not row boats. They are propelled by oars, and therefore it is more appropriate to call the ships with oar propulsion systems as “oar ships”, like in ‘steam ships’ or ‘sailing ships’.
There is more than one way to oar a boat than just pulling an oar one way to make the boat go in the other. Sometimes this is called “sculling” but that name has at least two meanings, that of the boat, and that of the method of rowing. Instead of sitting or standing facing aft (rear), the oarsman faces forward.
Regata a Cannaregio - Carnival Venice
In order for a gondolier to be certified, one of the tasks required is to move the boat sideways. This gives rise to a series of alternate combinations of rowing and “voga” on an oar ship for tight maneuvering in battle. It also reduces the width of a ship and since the oars often stay in the water, are not as adversely affected by waves as in the normal face aft rowing.
Historically, one viewing images done back then should note which way the oarsmen are facing or in which the oars are at too steep an angle to be rowed.
The Venetian Regatta shows the variety of voga sculling:
This is how it is done, under the description as “sculling” as a rowing style:
While the artwork of the Crusade Era was crude, it often was very accurate, despite problems of scale. In those days, people were more important than the things.
NO SITTING AROUND
There is a popular academic theme that the default method of oaring a galley required the oarsman to stand and sit. Just doing this without the oars, is enough to wind a horse.
While placing one’s weight on the bench in front, the weight of the body in recovery must have the center of gravity in front of the center of mass. Once the oarsman sits down, the inertia to get up again at the same time as the oars exit the water by clever twist of the wrist is overtaken by gravity.
MOVING YOUR ASS
The “Boys In The Boat”, 1936 Berlin Olympics
Unlike modern rowing on sliding seats, the ass still must move to move the center of gravity and strength fore and aft. That means standing is the best option to push and drive.
To be Ergonomically Correct and remain within OSHA guidelines, lifting and/or pulling requires that the weight or resistance of the object to be lifted or pulled (Oar), be focused at the gut or lower.
The Angle of the blade in the water (BIW) depends upon how much weight is carried by the ship, which makes the draught deeper (better for rowing) or shallow (not better).
The Ship “VALE CENTO” (worth 100)
This is a model I constructed in the 3D application known as PoserPro2012 consisting largely of “primitives”, some parts of other models (oars and sails) with a crew of 45 using the low resolution characters made by EPIC1 available at Renderosity:
Navigation equipment includes a sand dial, an Arabian “Kamal” (Search), and an Astrolabe, a late addition to the navigation tools available to a well-equipped Templar ship to determine latitude. Longitude had to wait for another five hundred years for a decent clock to be invented.
The Vale Cento main weapons systems are located on the forecastle (front bow) which is raised and covered with raw hide to retard flames. The main armament consists of a Tension Trebuchet and a Greek Fire Projection System. The tension trebuchet predates the dead weight gravity system.
In addition to your usual rock, spear and arrow suite, the projectiles thrown by tension trebuchet and free hand and stick methods included grenades containing caltrops, Greek Fire, lye (to burn the eyes), and grease to make the decks slippery. In addition to the Greek Fire Projection System, chemical warfare dominated naval ordnance.
The defense against Greek Fire, which burned on water, was to pour a mix of stale urine and vinegar. This gives rise, obviously, that the term “full of piss and vinegar” meant ready to fight.
The exact composition of Greek Fire is unknown. What is known is that it was short range system, that fired in short ball shaped blasts with trail and roaring noise. The recent detonation of Sodium Cyanide in Tientsin in China caused by firemen’s water hoses trying to put out a fire, suggests that Greek Fire could be mixed in varying degrees of volatility that include instant ignition in contact with water.
Fig 14 Dragon
Fig 15 Sling
The best technology readily available to project a mix of water and Greek Fire is the same system to make large fountains, by force of water pulled by gravity through tubes and projected out of nozzles. The simple solution on board a ship is connecting a barrel of water through pipes to a place where the Greek Fire could be mixed. This had to be well forward. And at the point of mixture, the pipes will heat up, hence best to shoot once the mix is mixed.
The higher the water source, the farther the fountain will shoot. The technical problems extant at the time was that hoses and pressure pumps were not invented until about 1650. Pressure vessels secure enough for boilers had to wait for the train. Water pipes were made of copper, lead, and wood from then until fairly recently. Valves to control water go back to Roman times. “A foot of height generates 0.43 pounds per square inch (psi) of water pressure, so a cistern does not have to be that tall to develop enough pressure to give a fountain a reasonable display” (wiki)
Fig 16 pipes
The Vale Cento places the source of water on wooden pipes that are fastened to the mast and just behind so as to not interfere with tacking. That requires a fairly long pipe to stay clear of the yards and make its way to the syphon (nozzle). Dromons and other Galleys of the era also carried a supply of lead sheets, which would facilitate making or repairing joints.
Fig 16 GFPS
The GFPS crew has at least two operators, one who pours the tube of Greek Fire (all reports say that Greek Fire was handled in tubes) into the GFPS Breach. The Operator below,
1. Makes sure that first both the Water Pipe and the GF Pipe are closed
2. Waits for command that water is being loaded, and confirms by touch.
3. Waits for alert that the Greek Fire is loaded, by signal
4. On the command to fire, the Operator opens the GF pipe until it fills the chamber with the right amount of fuel,
5. Shuts off the GF valve, and
6. Opens the Water Valve, until the Greek Fire is cleared from the nozzle
7. Shuts off the Water
Fig 17 GFPS
Great care must be taken in the storage and movement of munitions which, except for sharp or blunt objects react to water. Thus any leakage in storage will require frequent inspections, as well as the urine inspector to ensure that the right stench is in order.
Given the extreme dangers of chemical weapons of this era, it is essential that battle is best done with the weather gauge. As in up wind. There are a lot of stories about Greek Fire being dropped from barrels and boats onto the decks of ships, which, given Murphy’s Law, will be one’s own.
Fig 18 Grenades
SAILING THE VALE CENTO
Sailing the Vale Cento, like all with Lateen sails, tacking requires turning around, raising the main yard arm high enough to swing the lower (forward) edge of the sail across in front of the mast. This requires letting loose the sheets and catching them on the way back.
Fig 19 tacky
Then there is the problem of the six month cycle of winds and currents, but that is another story.
Gordon S Fowkes,
M.Ed., KCTJ, LTC USA RET