Tuesday, December 2, 2014

Drakkar & Dromon - Oars and War

Dromon and Drakkar, Oars at War.
Gordon S Fowkes, KCTJ

Both Viking ship and Mediterranean Galley played major roles in the Crusade as together they gained a few centuries of naval and maritime superiority until the Ottomans picked up where the Arabs had left.  These war vessels were often modified and expanded for commercial purposes and complemented the rise of the short fat sailing ships that was the life blood of the 12th Century Renaissance. They represented two distinct design and construction plans but which intermingled and married in the shipyards north and south.


Drakkar (Longship) and Dromon (Galley)

The Viking Long Ship was an exceptional sailing ship, with good to excellent rowing capabilities.  It was not long before Viking ships were shortened, the deck in place, and oars were stowed.   The Dromon was the standard Byzantine warship in the Mediterranean which became the warship of choice for all colors and creeds well into the gunpowder age.  Both ships were fast under oars and while it is now accepted that Dromons and other Medieval galleys were rowed with the oarsmen standing up.  Since the Vikings and Byzantines fought with and against each other including service on Dromons against Byzantium’s enemies, it is more than likely that rowing tips and ship design intermingled.

These ships had a high length to width ration in excess of seven to one.  Even as high as ten to one.  This high ratio plus the low angle the oars had to have lowered the freeboard to the point that rowing in rough waters was pointless.  The distance between rowing station (tholes, benches, thwarts, oars) on Viking ships was 32 inches, while on the Dromon it was a foot longer.  Therefore there is likely a wide variety of rowing techniques.  The paper Is  intended to muddy the differences.

Crusade Era crews were made up of free men already organized in fraternal, commercial, and military roles.  In fact the use of galley slaves is a rare exception in history and unsatisfactory when used. The collective skill sets required of oarsmen as shown here requires drill team precision and football ardor


The Boat Races

1959, I was a coxswain on the University of California (Berkeley) Crew, then consisting of the 8-oared shell.  That’s the little guy at the back (aft) of the boat with a big mouth with eight really big guys on the oars.  We used to race up and down the Alameda estuary for races and practice. 

In order to see what these ships and crews were capable of, one can look at You Tube:
“Holy Smokes, they are flying!”  An eight oared shell


Modern racing shells (solo to eight oars) use seats that slide, and so far as we know today, rowing seats had to wait the 19th Century.  More than likely.

Imagine one of those dromons with as many as a hundred oarsmen would look like in a final drive to close with the enemy.


The “balance of power” of the oarsmen exerted between port and starboard, and between fore and aft is critical or the ship will heel and wobble. 

Angles of Oars to Water.


In order to get maximum power between the oar and the water, the angle must be very low.   This was a major design feature of all galleys and Viking ships which also produced a very low distance between gunnel and water.  This made sailing any long and low ship in troubled waters short and wet. As a consequence oar powered vessels avoided rough water, hugged the shoreline and came on shore for bad weather and/or night.


The Galleys of the Mediterranean (later large galleys were used in the Wool trade to reach northern waters were built frame first.  They, like the Romans and Greeks before, drove through the waver rather than over. Unlike them, the ram had been removed and replaced with a prow.  The tactics changed from ramming to boarding.


 The Viking Long Ship was clinker built (hull built before framing), and had good sea keeping capabilities as it could bent and twist in rough seas.  Since the water far at sea was likely to have higher waves than on rivers, Viking traders and raiders shortened the length to width ratio to under five to one.  This modification together with decking the thwarts and relying on sail is what is depicted in the arts of the time.  They could not have raided across the North Sea to the Bosporus with a ship too long.

Therein lies the mystery, which is where were the oarsman’s hands, feet and fanny relative to the gunnel, oar, thwart and thole (oarlock).  The purpose of this article is to let in more dark to confuse certainty.  The short answer is that more serious rowing required standing, not sitting.  But more before that:

Oars vs Rudder

If the power of the port (left) is greater than starboard (right), the ship will turn to the right (starboard).  This requires the helmsman to steer to port (left) which throws the ship off balance, by leaning away from the turn;  the ship rocks to the outside of the turn which further unbalances the ship.  Been there, done that.
The selection and placement of oarsmen and their oars with a mix of the skinny, round, tall and short to keep that balance is essential.  While in modern rowing, the person has to fit in the boat, while that choice was not as popular back then.


Recovered oars at the same site often differ in length.  Some plans and pictures of the multi-decked ships show the outboard oarsmen with the shorter oar rowing closer to the hull.   More common are the images of two or more banks of oars, regardless of number of oarsmen per oar, having all blades paddle in the same row of puddles.


Most oar ships of the day normally had a flat deck from bow to stern, but not always.   Some ships placed the higher benches and longer oars towards the stern.  In order for the oars to synchronize, the bow oars (men) were shorter with the taller and longer, the higher. It also provided a commanding view of the crew for those on high.  That and the guys closest to the boss are tall by mutual assent.

When I was a private (E-2) short in stature I marched in the rear, and as is the effect of short last, the column marched like an accordion with the short on the run.  When I was a Captain commanding an Engineer Company, the tall came last, and the formation got short.   On the galleys of the day, the short came first, albeit backward.

 Gearing Ratio

The relative length and gearing ratio (balance) between handle, thole (oarlock) and blade affects the amount of leverage the oarsman can exert in pulling the boat across the water.  The ratio of oar inside the ship versus outside, defined by the location of the thole (hole, oarlock) as a fulcrum.   In the Medieval Era, that ration ranged between 1:3 (one third inside) and 1:4 (one quarter inside).   1:3 favors getting underway faster, while 1:4 favors speed once underway.


Catch and Release

All oars must enter and leave the water exactly the same time and angle cleanly to retain the balance of power.  Splashing slows the boat and the race is won on the run, not the drive.  In short when the oars are out of the water.   Catching occurs when the oar goes into the water, and the release….


The oars today are feathered on the run in order to evade snagging the blade on the water (ripples and waves).  This reduces how much the oarsman has to raise the blade/lower the wrists on the run versus lowering the blade/raising the wrist.  This distance must be changed as the seas get rougher.

In modern racing boats, this is all in the wrists.  No kidding.  The blade is turned by rotating the oars forward for the catch and back for the release.  The latter uses the rush of water to flip the oars out of the waters, in lieu of yanking against the water.


The historical evidence supporting this use of the wrists to make a clean catch and release is indicated by this old piece of statuary. 


The Run

The Perfect Stroke (Boston)



The race is won on the run not the drive.  A sloppy but powerful crew will be beaten by a precise albeit weaker crew.

 The essential difference between modern crew rowing and of the good old days is that today the oarsmen (oarswomen) is the modern sliding seat which allows full extension of the legs.  Since the upper body has about a third as much power as the whole body, the big mystery in scholarly studies of rowing has been to ignore that the legs were used in rowing in order to go faster than the other guys. Be they close ahead or astern.

Stand and Row

The short answer is that back then they stood and rowed, stepping forward to plant a foot or two against a load bearing member of the ship.  Those include other benches or steps for the purpose. The only time these oarsmen rowed sitting down was in port. This particular example is of a chained oarsman.  At best this shows that standing and rowing was not sitting down.
Later rowing systems based on Italian designs including rowing arrangement of more than one oar to a station, and/or more than one oarsman to an oar.  Crusade Era ships were one and one. 

These diagrams show illustrate the difference in height relative to rowing stand up or sitting. It is about 3 feet from the deck to the elbows and if sitting.

The basic issue of whether to stand or sit relates to the skeleton and muscular makeup of the body.   The sliding seat likely did not exist, and the amount of stroke an oarsperson sitting down is less than one standing up and moving. Key to this is the difference between seats whether bench or thwart (longitudinally) 


 The best ballpark figures I have, show that the distance between thwarts, tholes (oar locks) and oars on Viking ship are about 32 inches (.8 meters) and those on the Galleys were 47 inches (1.2 meters). The oars and tholes in Viking ships were exactly half way between thwarts, with the shield even with the thwart.   



Load Bearing Members Carry the Load of the Members
There is stress wherever the boat, the oar, the water and the oarsman meet and the net result of this stress is a boat in a hurry.  These occur in a sequence from where the foot and the boat, butt and bench, oar and thole, blade and water.  Anything but the strongest materials will cause the boat to stop running.

Leather padding or gaskets reduced the friction of oar on thole.  Some galleys do not have a round thole but a peg or more between which takes up the friction which allowed more than one oar to a thole.   

A standing oarsman on a Viking type ship such as the Knarr could get his weight and body strength stepping on the thwart forward or the smaller one under that thwart.  A galley oarsman normally had a step in front of his bench which was also a load bearing member of the ship.  This is what is shown in the Russian sample.


Precision, Decision, and Synchronization.

The subject of oaring boats is huge, with larger variations of equipment and technique.  This treatise shows only show a few combinations.   The drawing in Russian drawing above is one of a ship rowed by slaves (note chain).  The bulk or and primary choice of crews, however, were professional crews of volunteers often chartered by the maritime powers of the world. These ships and oarsmen were often rented out for cash, alliance or privateering.



Templar light galley- 40 oars, monoreme, crew of 45. Armed with Tension Trebuchet and Greek Fire Projector

No comments:

Post a Comment