Inca's Balsa Log Raft
The family of Guaras:
Dagger-boards, Center-boards and Lee-bords
The art of sailing is to beat close hauled to the wind
In South America the ship development was different.
They knew the dugouts and expanded canoes, as they used on the rainforest rivers, but not on their Pacific ocean, there they had other means. Their balsa wood is a wonderful material - the lightest wood in the world, and therefor instead of digging out the trunks, they tied more of them together and got a raft with a rather good carrying capacity and impossible to capsize.
A raft of trunks is a fine vessel and could have a long and fat central trunk as stem and keel, but equipped with sail they plunged in some keel-boards between the trunks to obtain a more stable course. Here they discovered the Guara-steering, but not the rudder. They could sail over all the ocean with their heavy loaded, but slow moving crafts, and they were beating so effectively against the wind, that they without greater problems could return to their starting point. There they were in their development when the Europeans came and took over the control. The Europeans recognized the men of the coast societies as efficient seamen and sailors, but they never understood how the Guaras worked.
For the Europeans the function of Guaras has been a mystery in hundreds of years: The outside world simply hasn't understood how to use these daggerboards, but nevertheless the South Americans have used them daily on their ocean sailing rafts.
Leeboard - the family to GuaraThe Guara /daggerboards wasn't totally unknown for the Europeans. The fun is that similar system - as cousin to the Guaras - has been used several hundred of years in the northern Europa in the form of leeboards.
The Dutch did not invent leeboards. They saw them being used in the Far East during their discovery voyages in the early 1500s. In China they have a documented experience of more than one thousand years.
The result of this learning we saw on the Dutch rivers, canals and inland waterways, the German Frisian and Waddensea coast up to South in Denmark. All over, up and down the coast of East England, on the rivers Thames and Humber we had these 'daily work horses' in form of flat-bottomed and shallow drafted boats as Sloop, Barge, Keel, Ewer, Tjalk, Seascow, Botter, Kaag, Kahn, Evert, Curonian et cetera - all without a keel. Ewen far away, on all the shalow lagoons along the Baltic coast of Germany and Poland up to the Curonian lagoon between Lithuania and Kaliningrad, they sailed with their flat bottom and leeboards.
13 century junk with both lee- and luff-board
showing its shallow draft
showing her flat-bottom
Unlike the Guaras, the leeboard is mounted outside the hull and normally one on each side - obvious for not to affect integrity of neither hull nor hold - and they are placed midship, very central on the side of the 'Center of Effort' of the sails, for not to disturb the effective trim of their crafts, as are steered by rudder.
LEEBOARDS were principally used to stabilize the course by reducing side-sliding of flat-bottomed sailboats, as couldn't have any natural keel - mainly because they needed to sail, land and beach in shallow waters or on riverbed by low tide. Up to 6 degrees closer to the wind, than the same boat with leeboard up - is told us.
But the sailing people learned that leeboards could be a great help as pivot-point turning through the windeye under a tack, and with a leeboard hanging several feet below the ship-bottom, they had too a good warning against banks and ground, when sailing in shallow waters.
We have never heard of two leeboards mounted on same side; and therefor neither the Chinese nor the Europeans never discovered the Guara steering qualities: to balance the side-sliding between for and aft.
From leeboard to center-board
The outside leeboards were used in centuries until our evolution in ship-technology was able to construct safe and reliable wells inside a hull, what happend around 150 years ago. Then leeboards in some yacht-designs entered from both sides and joined in one single board - called center-board of course - more as ONE adjustable keel, later on too as a counterweight - and easier to handle than TWO leeboards on same boat. Leeboards are hinged and centerboards too, whereas a daggerboard is a board pushed down in a sheath like a dagger.
Inside her well for eels this eel-drifter has mounted a center-board.
Examples of similar physics balances:
There are hard-core sailors as declare, that they can sail their boat without a rudder - by 'playing' with their sails only.
That is a balance between 3 forces on same line.
And that is what we are doing on our craft.
And that is exactly what make the things work.
Another photo of Dirch with his 'astern leeboard' >>>
The steer-oar of the Vikings
The Viking helmsman knows perfectly, that his ship with wind from port will heel and dip deeper its side-mounted steering oar as therefor react better - in contrast to a Starboard wind, as will lift the steer-oar more out of water.
The steer-oar on viking-ships is considered as a rudder, but due to its design and place, it too has some qualities as a sideboard - just as the Guara.
Viking ships too can tilt their steer-oar around the withy, and that they normally do in shallow water and when beaching. Laying the tiller down to lift the oar from the bottom - and then land on the beach.
Tacking, change windward side
When changing leg every ship can either tack up through the wind-eye - or wear the other way around - turning her 'behind' against the wind - and which one of the two turns you should use, depend of your rigging and sails.
Mono-masted square-sailors have no difficulties to wear, they turn as a cup on its saucer, but tacking through the wind-eye can give difficulties, if the vessel haven't sufficient headway in her run-up to reach the wind-eye. With no foresail and without streaming water around the steering oar the boat will be driven backwards again, and the manoeuver have to be repeated.
as we can tilt
1): On smaller boats, you can use an oar in the lee-side to row the boat through the eye.
2): You too can let some crew-members to go forward to weight down the bow of the craft. In this way they move forward the CLR = Center of Lateral Resistance as play together with the CE (center of effort) of sail as then may blow downwind, and bring the boat up in the wind eye.
3): Theoretically there is this third trick, as I still never have seen carried out. Let the helmsman tilt the steer-oar up of water so the aft-end slides easier away downwind for the mast - and then swing over the yard, dip your steer-oar and sail-on on the other bow.
Note: The same trick of moving the 'live ballast' of men forward, in some cases too can get the boat to beat higher to the wind - moving ahead the CLR.
That is a maneuver to stop the boat with sail still hoisted - to wait for somebody or to pick something up. With the sail hoisted the boat behave more calm and under control than without sail - drifting slowly sideways under press of the wind.
The manoeuver for mono-masted is in general: tacking up in the wind eye, go through and get back-wind, and then - without to turn the yard but only rudder - let the boat go astern until she stops with full back-wind in the sail - yard still along and wind directly abeam. If the boat is well trimmed she will stay there, drifting sidewards.
If not trimmed, the boats with steering oar have the option to tilt her steering oar to change the underwater body and keep a balance.
This option the square-rigged Nordlandsboats can't use, because they are equipped with stern rudder (pintle and gudgeon) and not a steering oar - but of course here too a simple rowing oar could help to keep the balance.
Another task utilizing side-sliding
- balance the CE contra the boats CLR
An eel-drifteris a flat-bottomed fisher boat, as work drifting sideways, hauling a drag-net along the sea bottom.
Having more masts and sails, the trick is to control their drift balancing by their sails - as indicated earlier.
The same way of fishing: hauling a trawl along the bottom while drifting slowly sidewarts was too used in the shallow lagoons along the southern shore of the Baltic sea.