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- Summary
What we know
What we NOT know
Material & Tools
Fate of Log Rafts
Guara steering
Hull Shape
Sails on Rafts
Modern Gear
+ Addenda
[ img - inca-sol.png ]Quechua
[ img - tumi2.gif ]Hotel in Lima
Boats of Pharaoh
[ img - egypt-image.png ]Thousands of years ago
INCA Tupac Yupanki expedition
[ img - inga.png ]year 1465
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Incas' Oceangoing Balsa Log Raft

Today options for raft Yachting

Parameters for all sail powered crafts

The wind will catch the craft in what is over the water: hull, hut, mast and sails - heeled or not heeled - and blow it along. And the boat will resist this movement by its hold in water = her underwater hull - heeled or not heeled.

It is only the sails as can split up the power of wind in a forward directed force and a lateral cross force. The rest of wind's attack-points on hull, hut and rig can not be adjusted, and is only to understand as a unchangeable wind catcher.
And the boat will respond to these two forces of wind resisting the wind's blow with her actual underwater hull whether heeled or not heeled - braking the forward and lateral movements with her forward and lateral hydraulic resistance - as fortunately is constructed as LOW respectively HIGH.

In short we can say that a sail powered boat has only two factors as skipper can influence in favor of his sailing:
CLR - Shaping the underwater hull for its way through the water - by rudder, steer-oar, Guaras and heeling, as all change the underwater hull.
CE - Modify the rig with its sails set for the weather - moving center of wind attack between the sails (ahead or abaft), sheet-in sheet-out and reef as both influence on the heeling too.
Practical note:
- that is only the scirntific sailing, as is limited by its credibility
The rest of the vessel as hut, hull and rigging is outside action. Changes here is task for a shipwright.


The strict scientific sailing - treat with credibility and trustworthyness

If the purpose of a raid is a maritime research as Heyerdahl started, then you are tied to the past and can't accept greater changes from old-time conditions. That knows the specialized museums such as those in Roskilde and Oslo: as original as possible ! Their aim is to recuperate and regain old knowledge and lore: What could our ancestors - and how did they?
Archaeological investigations have their rules to prevent fake, manipulations and to maintain credibility. So are the conditions of serious investigations of the past ! They have only space for scientific experiments - well documented.
Scientific sailing:  
NO to anachronistic materials
NOR anachronistic technology,
NOTHING imported from other part of the world
   - and that means:  
NOT iron -
NAY to stainless -
NOUGHT of plastic -
NEITHER of any other synthetic material
In relation to this, I dare say, that only a man with a fire in his heart as Thor Heyerdahl would venture to sail out on an ocean with a minimum of modern equipment to verify a scientific theory. He only brought with him a simple radio and a typewriter.


Free raft sailing where modern materials and gear bring new options
- and as everything on the sea is permitted, then -

Statement from when the world was young:
Every free man is free to build his own boat as he like, for then sail out on the sea
- without need to ask any authority for leave nor to ask for any approval -

So it was then - so the free world still is - and so we want it to go on.

Nobody says that a raft has to be of oldtimer style
If you are fallen into the familiar trap of mistaking adventure for science, we can't help; but if the purpose with a navigation only is to enjoy, to sail, to get a kick on 'your hunger-sense' for own adventure, to wave your national flag, to become famous, or to shoot some minutes of entertainment for a film or TV channel, then you are not bound by any art nor scientific truth from the past.
With a buccaneer's wry grin, you can say:     "We freebooters are free, and can do as we will"   - - - and then do it.

Of personnal, official or safety reasons you therefor can employ something more modern. All these natural but old-fashioned materials on an Inca Balsa raft you can improve or change out with something "better", more nice, more comfortable, more "convenient" - or more safe.
I am not talking about a "pseudo-safety" - that is for those people, who never dream to run a bike without bike-helmet, they are lost to the system - - - but we have to realize something about safety = avoid to provoke an unfortunate and disastrous occurrence. So don't leave without rescue equipment - our modern societies don't accept that type of loss - even more thrilling.

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on sea
is possible!

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simple -
as well as more

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Even if you have no important archaeological or scientific purpose with your raft - then you at least could pick up any investigation as could give cover or serve as business-model - just to justify your choice of a balsa raft for your raid.

As freebooter you can allways try promote your raid and call more attention to your case by for example emit a hype: that you are going to make some scientific research. This mainly to feed a hungry press and build up an image of yourself as a serious and professional skipper.

Post-Heyerdahl propaganda advise:
Every hint about the name Kon-tiki or Heyerdahl could be extremely useful in relation with the press.

But if you only want to meet the sense of freedom on the sea, to escape from a chaotic world, to gain the adventure of your life, to "survive" as "survivor man", to feel as naval hero, to be named in Guinness World Record Book or whatever explanation you will use for your raid, then you can build your yacht-raft as you will, equip it, stuff it up with technology or the opposite, fill up your pantry - and then sail off.

But don't forget that: a tiny group some month alone on a small raft is a hard and long-lasting social experiment
- without escape other than a long swim -

And with that in mind we recommend to put much attention to the welfare and comfort and perhaps privacy of each 'cellmate' under this month long confinement.

building of a log raft

Buoyancy - unsinkable hulls and anti-water-logging of trunks:

Many reed-rafts sail out with a steel body covered by totora reeds. The authorities demand that for sailing with tourists at Lake Titicaca. More particular reed-rafts we have seen too with hollow plastic tanks or polystyrene foam-blocks (Styropor or Styrofoam) hidden in the reed-hull. Don't forget that totora reed only have a working life between 3 and 10 months before it rots.

Of the twenty log rafts as the last 70 years have headed out on the Pacific Ocean only 8 have reached their destination, and some in such a state that whey wouldn't have been able to return to their port of leave. So pay attention to buoyancy - and pay attention to the Teredo Navalis.

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<<< Tar treated heads

In all historical time we have always impregnated our wooden hulls with tar. What they did in Inca-land is still not known

NOT treated saw-cuts >>>

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Wood will soak water. That fact is difficult for a modern man to accept, so he will find something else to impregnate and seal his wooden trunks.
In historical time we impregnated our wooden hulls with tar. We don't know when tar came into shipbuilding, but we have no sign of tar (nor 'tung-oil') in our South American balsa area. Perhaps the sailing people have had something similar to waterproof their trunks, but we have no evidence.
Today we can protect trunks by a coat, or we can enclose these nature-created plant materials with a waterproof surface of something like plastic, epoxy-glass, metal coat or similar. Secured in this way against water-logging, we obtain a more safe and perhaps we too gain more seaworthiness or more carrying capacity.
Next step in development is to change out and totally replace the wooden trunks with oil barrels, bundled plastic cans or bottles, special shaped tanks or closed industrial tubes of HDPE (High Density Polyethylene) equipped with a welded end-cover. The only recommendation is: if the craft is expected to last more than a couple of weeks, don't employ anyhing of biodegradable plastic, that will decompose in short time.

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 <<< Modern bindings of webslings on raft An-tiki

Traditional Sisal-rope bindings on raft Kontiki2 >>>

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Joining trunks
The floaters we can weld, attach by fitting, lace or tie together. Not many modern men will rely on natural fibre ropes, as the Incas needed, they will prefer synthetical ropes. That is no secret that synthetical ropes hold a higher strength, they don't absorb water and are furthermore resistant against decomposition. Decomposition, in the mind of any modern sailor, easily exclude ropes of natural fibre incl. Sisal, Manila and Hemp and favour Nylon, Polyester, Polypropylene or better, and this includes steel-wire used for a standing rig. Therefor the most common concept today for tying logs together is: Synthetical ropes !
Even if the most 'original' rafts sailing out on the Pacific are using ropes of 'natural fibre', as they say, then that normally means sisal or manila, as in no way is material from South America - sisal from China of course. In South America they had other fibres - not sisal!
The modern web-slings of man made synthetical fibers is too a resistant option for tying "trunks" together. We have seen it used.

Joining wooden trunks on rafts we sometimes "see" the logs nailed or bolted together to secure a reliable fixture. "See" is in quotation marks, because that type of fastener normally is normally covered discreetly by decorative rope-bindings. Fake or security - who is able or who dare to judge?

Don't close your eyes for modern options

Some examples of extreme luxury oldtimer replica-yachts
- perhaps exagerated, but good for reflection -

The extreme modernized viking-inspired Valtyr is a very advanced replica from Iceland with aluminum mast, servo-controlled sail and motorized windlass. She can probably be sailed singlehanded - but no information given about that.

Some rather fine "oldtimer" yachts
Tangaroa2 - and Kontiki2
All the 3 rafts was balsa-rafts and perhaps "replicas" of Inca-rafts, but in spite of their modest appearance they ware stuffed up with high-technology by an enthusiastic tribe as hardly can live an off-line life.
Equipment on the Tangaroa2 included GPS (Global Positioning System), F-77 satellite antenna, AUS (Automatic Identification System), six solar panels to generate electricity, wind generators, desalination equipment, telephone, Internet, 3 Apple Mac iBook computers, DVD player and an iPod.
Tangaroa2 and the Kontiki2s were both a repetition and too a contrast to the 60 year earlier Kontiki voyage.

Crossed the Atlantic Ocean 2011. This raft An-tiki gave the four mature "survivor-men" a wanted experience of waves and wind on an immense ocean.
An-tiki was a technical astonishing raft made of 4 supply water pipes of HDPE replacing the wooden trunks. The raft hold throughout technical constructions with many interesting details, as is demonstrated on photos - but didn't get famous for its seaworthiness. She was equiped with 4 Guaras, two stern-rudders and one steer-oar, and only the last worked - but no evidence is left - they didn't publish anything - how to navigate a raft by Guaras only, because probably they didn't. Result: One more ZERO experiment !
But studying their photos, it seems for example as the short distance from mast to forestay wouldn't permit an adequate adjustment of sail to go for a wind abeam. Too the forward daggerboards placed close to the mast, indicate that the raft was mostly build to sail with wind from behind. And that was what they did. Choosing the old trade wind from Africa as every sail ship since the Carracks has done, they didn't need more than run for the wind - or maximum broad reach - to land in Caribien. Just as the route of a balloon.

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[ img - Antiki-undersail.jpg ]

an original Inca-rigging is NOT known - so everything is possible

Mast, sail and rigging +
whatever gear and mechanical equipment of any art for use on your raid

Thor Heyerdahl around sails: "We have very good reason to assume that both the rectangular and the triangular sail were used in Ecuador and Peru - then as now."

Original rigging for balsa rafts is more or less unknown and unverified, so therefor we see types of sailing raft rigs coming in from all parts of the world. Seems more as a product of the captains own sail-culture, and therefore what he masters. Nordrøn square sails for Norwegians, Latin sail for Latins and probably Junk-rig for an Asian captain.

Primitive relatives to blocks - without "wheels":
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Disks and blocks are today natural for rope handling, but nothing of this stuff is found in South America.
The difficult question is: what equipment for handling of sail the South Americans have had, because their culture is famous for not to have used wheels. Or better 'seems not' to have used wheels, and that indicates an uncertainty, because they probably used rolling trunks-pieces to move heavy things.
Nevertheless - we understand very well why they hadn't developed any carriage with wheels for roads, at least if we have traveled in their steep mountainous country.
But what gear did they use handling ropes on their oceangoing rafts? What about gear without sheaves as "dead mans eye", bee blocks, bulls eye or thimble of hard wood - was that possible?
My guess as engineer is, that the inner-lining of a sea-conch could have been used in the mast top, being hard, smooth and shaped to let a halyard-rope pass.
We have to find an answer to that question, but until then we must accept to use gear from other cultures as disks, blocks, tackles, winches etc. in varied versions.

The Kontiki of Thor Heyerdahl was equipped with square sail and topsail on an A-mast. The next 60 years the most rafts in his wake too used same square rigging with same A-mast until - surprise - the latest Norwegian Kontiki2 rafts only mounted one pine mast type Nordland, as is original of their Nordic culture. Probably we have to wait many years before we will se a Norwegian sailor mount a Crab Claw sail on his raft - that isn't his culture nor nature.

There are no reasons to use ropes of natural fibers as long as we don't know which natural fibers the pre-Columbian sailors used. We are free to use whatever
- too the synthetics
- - - that has NO archaeological importance
Synthetic ropes, double blocks and turned fitting are in no way Inca, but seems very used and popular introductions on replicas of Inca raft
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For modern standing yacht-rigs are often used steel (stainless) wires or sometimes chains, and for the running rig: the flexible ropes. And all modern gear to handle ropes we can get easily from the yacht industry. Everything from blocks and sheaves to handle, fasten, tie, wind etc is at disposal - and is used. Even remote and servo controlled capstans and winches together with automated furling and reefing systems. Tested thoroughly, ready and reliable to use on every craft - too on log-rafts.

Even on a balsa raft as Tupac Yupanki - which is named after an old Inca sovereign - the crew is very fond of modern yacht gear
- - - for reason of scientific investigations, they explain - - -
[ img - TupacYupanki-winch.jpg ]

With modern maritime equipment as capstan, blocks and pulleys of metal or nylon, steel rig and perhaps a built wooden mast or one made of aluminum, with or without reefing system - then we will have a perfect sail craft, which will be loved by authorities as IMO, STCW, SOLAS, MARPOL and others, who should maintain a certain control on safety in professional and business navigation, and in the most cases at least have to issue the official permission to sail out. Those authorities today employ lawyers and engineers - but not sailors.

Sails today are made of material as Dacron or Duradon eventually sewn on a computer controlled machines with synthetical threads. They are lighter and easier to handle than sails of nature fibers as flax, cotton and hemp and don't decompose so easily. They are recommended. Square sail is named by the old Spanish chroniclers and as mentioned it is often used on rafts, but no only, as Thor Heyerdahl point out. We frequently se rafts with stay-sails and topsails. The preference seems more or less the skippers taste or culture or what he has learned as child.
The square sail is known to need more hands to handle, and is therefor rarely seen on singlehanded crafts - whereas tall ships as school-ships, with many cadets to employ seems to prefer square sails.

what was placed visible over deck, we have several descriptions

Superstructure, cabin and deck pod

The hut, poop, cabin - as was mounted at least at the larger Inca raft - was by the Spaniards described as a cottage made of sticks and canes thatched by broad palm leaves - on the bigger rafts in two floors - first floor was for goods and second floor for passengers. Always placed behind the mast.
Thor Heyerdahl sailed out with a poop - or better to say cottage - as described by the Spaniards, later on came plastic foil to line a hut inside, and the last rafts had only this thick plastic tarpaulin without any cover for camouflage. A tent on its frame.
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The hut on the old Kontiki of 1947


The tent on last Kontiki2 of 2015

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A raft is a "WASH THROUGH" vessel, so think ahead how to get crew dry and warm again after the wash

Recommendation: With the chance to spend several months on a raft of 100-200 square meters together with the same few men, that isn't the place to promote yourself as a hardcore guy - that you will need to be in all cases. You have to build up a reliable team and keep high morals. Put instead your attention on something to make the cruise comfortable and the life on board pleasant - and that include to give the maximum privacy as possible (own bed, own store-box, good cooking etc) and if your plan is to sail outside the warm-weather areas you have to turn them both warm and dry even when they get drenched -

The deck pod of An-tiki raft was made by bended corrugated metal plates. A cabin nice organized with its 4 bunks, just as on a luxury yacht. In no way as the earlier rafts, as showed up more as an improvised boy scout camp.

[ img - antiki-raft+hut.jpg ]
The cabin on the raft An-tiki seems in many technical aspects more up-to-date


the internal of the cabin too is made comfortable  >>>

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Fresh-water supply

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Modern raft build with saw cut timber is loading fresh water for a long raid, before craned out in water. > > >

Note the roomy space under deck for cargo and supply as too is useful to store 80 plastic bottles of 20 liters, as could go brittle in sun and then burst.
We are told about 'reed raft vessels' as are without room under deck, and therefore storing their water-bottels on deck - with serious loss as result.
We are not aware that any pre-Columbian raft has carried bottled drinking water - but perhaps they did in some way. Perhaps in ceramic amphoras or in calabas /pumpkins.

Nevertheless, the pipe-raft An-tiki impressed us by the idea to use of some of the traverse tubes as fresh water tank.

Why not a motor-powered propulsion?

With the purpose to take a photo - a selfie - of his craft on an immense and lonely Pacific Ocean a modern sailor probably too will bring on board a little dinghy - not with oar, but with motor om board - and today too a toy drone with a camera.
A rubber dinghy too is useful for going ashore outside harbors, but it will neither be better, more safe nor more authentic than a doble canoes type Milanesia or Tahiti. The sad is, that a rubberdinghy will not cope the South Pacific tradition, but on the other side every modern seaman of today will feel better, because a rubberdinghy is more in accordance with a modern sail tradition and his dominating maritime idiosyncrasy of today, as not is specially familiar with sails, but hangs more to a sea-extended driving of a car.
But why not a motor for the raft, or for your replica of what sort she is. If you are aiming to sail with tourists or passengers, that could be a good thing to have at disposal.
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Luxury vikingship Valtyr with her discreet placed motor
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Atlantic cruising An-Tiki raft with her outboard motor
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Vikingship Nidhug, showing her screwed behind

If we want something more powerful to gain speed or for missing wind, we could cleverly bring with us two outboards or one bigger main, bearing in mind, that our raft hold a big central trunk, so a single drive therefor should be asymmetricaly placed, what is OK for outboards.
Outboards are very fine to a raft, because they too work as rudder. But if we mount a conventional motor hidden in the hut and a long shaft going down between the trunks, then we have to plan with a classic rudder, because the Guara system work only together with sail and will not be able to function with motor propulsion.
If our worry is fuel efficiency or storage for a long-distance raid, it probably is better with only a minor economical motor in combination with sail - a tiny outboard as a active rudder, a motorized oar for harbour manoeuvre - or as a truster, to restrain the leeway and make the raft beat higher to the wind.

the influence of high tech engineering on our conditions

Navigation in the time before GPS - and after

We have lost the sense and power for a non-instrumental ocean navigation
The sense for nature-given navigation, the modern man has lost, and he depends today on GPS, charts, radio, radar, AIS, satellite connections, echo sounder etc. Nobody to day can do what the oldtimer sailors did, in their riding around among scattered islands, and that is many years ago I have met a captain rely on his own observations with chronometer, sextant and tables. But as claimed, the advantage is clear: Even a boy scout will to day be able to hit Easter Island in his dinghy and with a handheld GPS.

As said, to day we can't do much without these electronic navigation aids and communication systems; though we ought still be able to sail the oceans at least with compass and sextant.

For costal only sailing we don't need these instruments. Everybody can navigate along the coasts as Odysseus did.
On the other side, we with these electronic navigation equipments we will never miss a far island, as the old sailors could risk.
Don't forget that many west-going Vikings got sea-wild and passed south of Greenland - and of this reason they hit America 500 years before Columbus. They found Vinland and there they settled with some colonies. And of those sea-lost sailors some could find their way back and tell, what has happened - but only some - the rest disappeared - probably against south.
And to terminate: Listening to these old legends and sagas around Vikings, Columbus KNEW there was a land to find out far west, and therefor he set off from Portugal. His only mistake was, that he thought it was India.

An automated future

Today we have technology to send crafts, drones, space rockets and missiles over long distances by remote control and without any mate on the helm. In these years we are planning unmanned sea transport systems for the near future. On the ocean today we can meet sailing square-rigged crafts with full servo handling of sails, that reduce the need for hands of crew.
The Handling of daggerboards we can automate. If we make the daggerboards of steel or stainless and hinged in a corner, we can lift them up and lower by small servo motors. That doesn't change anything on the raft steering principles, but are making the handling easier under our cruise - but less need for crew.
And furthermore it could be useful with a build-in an electric truster to employ together with or use instead of a tugboat for near shore and for harbor maneuvers or beaching. Eventually combined with a minor outboard motor. No greater problem - except money.
The extreme modernized oldtimer Valtyr is a very advanced vikingship from Iceland with aluminum mast, servo-controlled sail and motorized windlass

- easy to sail singlehanded

[ img - Valtyr+anchor.jpg ]

Power harvest
- the Heyerdahl era with kerosene light has passed -

The need for modern navigation and communication equipment - to fulfil the claims from authorities and insurance - make it useful with a power-harvester as can produce electric power and store it on accumulators to use for radar, echo sounder, internet connection, radio, satellite telephone and the electric light together with what there are of personal equipment on these crafts. The system could be photo-panels on roof and wind-generators or something in the streeming of water - eventually in combination with an emergency gasoline generator.
<<< Instalation of Power Plant

on the right photo: >>>
A well-equiped raft with satellite antenna, photo panels and a wind generator as are seen clearly on the Photo together with two life rafts and a life buoy

[ img - Tangaroa+internet.jpg ]

With a such electric installation we have no reason to bring with us kerosene-equipment as lanterns, stove or petromax lamp.
Old-timer cooking by firewood we have left many years ago except perhaps for a charcoal grill. All equipment we can make electric, and cooling of food and beers together with freezing of provisions we expect done as in every on-shore kitchen. The cooking itself we today probably will do by gas carried in cylinders.
These installations will make the cruise more comfortable and do no harm to the raft experience.
So take care of the galley and care about the cook. Don't forget that the cook is the most important person onboard.

Of further installations as could be nice to have are: a modern personal bathroom with water closet, hot and cold water installed together with a shower bath - but too a de-salinator for making drinking water out of seawater.
And if you have decided not to have a motor on your raft, then take at least some rather old-fashioned 5 meters long oars with you instead of paddles - exactly for harbor maneuveres and the near-coast-case, beaching and so. Oars are not inka-equipment but they work better than paddles.

Conclusion of Free Raft Sailing

If the purpose is to sail - and only to sail - then you are not bound nor limited by any oldtimer condition. You can use all what you know and have learned around sailing for your raid, and you can labour and protect your craft as you personally like. All technologies as mentioned above, any material and modernity from the yacht industry are at your disposition.
But for a wood build vessel you must take care of Teredo Navalis. That clam has sunken too many wooden crafts. Perhaps a modern process employing pressure or vacuum impregnation of the buoyant trunks could be a good idea to contemplate - for your own survival.

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Lima - Oktober 2019 - Seventh edition of this paper