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#8 Third Edition:
[ img - raftlogo.gif ]
SPROG
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INCA
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Inca's Balsa Log Raft

The case of the Square-off rafts


When things turn wrong, what is the reason ?

- and what can we learn from that ?


two more rafts lost on sea
The story - short.
That is not every day we hear about a square-off raft driven by sail, but the Norwegians created and builded two - and they paid a hard price for that experience.

They came rushing down to our coast, build two new models of Kontiki rafts, sailed out on the wide Ocean without previous test of their new design, and discovered on their way, that they with no combination of sail and Guaras were able to beat against the wind.
Nevertheless they continued their sailing and drifted with the trade wind, as brought them out of route. After some months drifting around in the South Pacific, they found themselves without possibilities to sail back to South America, and decided to abandon their rafts in open sea and call for pick-up - and with that they gave up every chance to recover their costs and regain investment.

- 12 of the 20 rafts sailing out on the Pacific Ocean, never reached where they should
Why tell this story?
Nobody think that this was a happy experience for the crew - although unforgettable. Drifting far out of planned route, turning south to catch the cold roaring forties where the western wind destroyed their rafts and washed through the crew and equipment. Such months on sea are not fun, but we have to admit, that hard and bad experience too is experience, as could be fruitful next time they - or sombody else - want to try again.
This is a sad account, but we to tell the story to extract learning for common use.

Rule for Guara-steered rafts:
If a raft can't beat to wind it is NOT a Guara-problem
- the problem is either the hull, the sail or missing seamanship -

What went wrong for the Norwegians ?
They had made changes to the classic inca-raft bodies - the hulls, but they had carefully tested their theories by tank-tests.
They had mounted a typical Norwegian mono-masted square sail, and that rig is the most Norwegian rigging, as is possible to imagine. They have used that rigging the last 1000 years - and they master it to excellence.
It shoultn't neither be their crews.
The rafts had all experienced captains and around the half of their crew were full-bodied sailors trained on square sails - the other half less.
They came with the experience from a successfull raft-raid - Tangaroa2 - as 10 years earlier drifted west over the Pacific; so they knew that ocean - and they knew the use of Guaras.
They too knew from the old Spanish chroniclers, that the chosen months would be the worst to sail to Easter Island. Impossible in Inca-time.
Too they knew, that the year was expected to be a bad 'El Niño' year, as affect the global climate with atypical and unpredictable weather - and they felt themselves strong and prepared for such conditions at sea - and they were!

Their fault was NOT to make an erroneous design - that could have been mended
Their bad result was basicly due to thoughtlessness
- and the headless was, that they sailed out without previous test of their new creation -


Analysis of chosen square-off hull shape

The first suspected is the new hull of their rafts.
The testimonies from early explorers all have told us, that the South American rafts without visible difficulty could beat against the wind steered by their Guara system. The common shape was reported as a long trunk in the middle and some smaller along the sides - as the shape of an outstretched hand.

That the norsemen changed. The rafters wanted to build "a fast sailing balsa raft".

Transcript from www.kontiki2.com 2015-09-03:
"Building and testing raft models - How should one best build a balsa raft? Pointy front? Shaped logs? Does it make a difference?
Crew member Ola Borgfjord has built several models along with his father, Einar Borgfjord.
The results indicated, that a curved front and tapered logs in the back will be a good choice for the rafts."

[ img - tank_test-rafts-sept.2015.jpg ]
Tank test at Technical University of Norway
pure traction straight forward and no sidewards forces

The group carried therefor out comparative hydraulic tests in a water tank, measuring water resistance in relation to sail-speed for different raft models. Subsequent both rafts were remodeled and constructed in accordance with the scientific result, as the tank test had indicated. They amputated the prow from the classic balsa raft and build a pair of tween rafts for their raid with square-off bow: 'stub-nosed and sloped'. They maybe could reach up to the double speed with this new hull shape, they expected.

Such a tank test probably is fine for motor powered sailing, but we are not informed if they had carried out any test of their models for things as 'influence of wind abeam', 'directional stability' etc. - but the result was fatal.

[img - Prow-Kontiki2.jpg ]
The prow of a kontiki2 raft the day of launch

As told, they build and sailed directly off without test nor trial of their new hull shape, and a month into their sailing, we received the message

Cite: "We can't sail closer than 100 degrees from wind, 90 degrees is not possible, no matter how we position Guaras and sail"

We have still not received any final report, but 100 degrees to wind is in no way against the wind.

RaftOnOcean+.jpg
Photo of Kontiki2 raft Tupac Yupanki, taken 25.Febr.2016 by a toy-drone
First Analysis
The raft shown on their air-photo make an extreme broadside motion. She holds a rather rectangular shape, with a l/w ratio around 3:1 and a transom prow - she seems to use her starboard (lee) corner as prow. The position of the Norwegian flag indicate wind directly into port side = beam reach. The lifted front-end of port trunk together with the dipped starboard trunk-head indicate a good wind. The wake drawn from port side bow and too after the raft both indicate a leeway - a deviation from pointed course (centerline) of around 20 degrees - and that is much.
The yard is turned 60˚ to centerline = 80˚ to sailed course. The sail seems adjusted fair, but not good for a wind abeam, if sailing along the centerline of the craft.
In this case the raft is NOT sailing along any centerline, she is sailing along a diagonal
This photo gave us impulse to investigate the general theories around hull shapes, as described at web-page #7

As we afterwards evaluate the case, the performed tank-tests demonstrated, that a rectangular hull could be pushed or towed rather well ahead in flat calm waters as announced - but more tank tests, as for example sailing along the diagonal with a front corner as prow would probably have shown nearly same low forward resistance.
A throughout investigation for sail directions all around the compass could have shown something like this sketched oval vector field, where the diameters hold nearly same relation as the l/w = 3:1.

We don't know, but are nearly sure, that the test rig of the tank didn't register nothing about any torque from a one-sided bow wave as showed up as fatal for the rafts. They registered probably only draw on their rolling test-bridge, because that was what they were asked for, and that is okay for any motorpowered ship, as we build today.

[ img - vector_field.gif ]
Vector field showing theoretic size of water resistance all the way around a rectangular body

A sailship is characteristic by her low forward hydraulic resistance - and her high lateral ditto.
We don't have much experience with transom stems, but it seems as such vessel has no clear saildirection, because all the zone between the two diagonals will give nearly same low hydraulic resistance, and it furthermore seems as this Norwegian raft has chosen to sail along the diagonal passing through lee front-corner. The photo show, that she is sailing around 110 degrees to the wind, even if 100˚ acording to their message should be possible.

It looks like the norsemen have created a vessel with twin-prow.
The vector diagram indicate, that sailing forward in any direction between the centerline and a diagonal - or rather: forward between both diagonals - doesn't offer much difference to stabilize anything. Bistable we could call the craft, because the wind will decide to which side the raft shall flip-over.


The tricky transom bow
A hydraulic 'flipflop' construction

unstable as a standing egg [ img - egg3.png ]
of Columbus

[ img - 5raft+inclinA.png]
<< fig.A
[ img - 5raft+inclinB.png]
<< fig.B
[ img - 5raft+inclinC.png]
<< fig.C
[ img - 5raft+inclinD.png]
<< fig.D
[ img - 5raft+inclinE.png]
<< fig.E
fig.C):  a square-off raft will probably be able to keep a straight ahead course - if not disturbed by any wind across = sailing downwind.

fig.B and fig.D):   Unstable positions.
With minor unbalance, the lee corner take over the governance and divide the incomming water in two streams - the raft then will tumble over, due to the torque from the one-sided deviation of the water and end as indicated at fig.A or fig.E

fig.A and fig.E):   When the two streams reach same size, a flat-bottom raft will find her ballance sailing along a diagonal just as a kite.

Notes about counteract options

We can't eliminate the "square-off problem" because the "flipflop-effect" when the bow-flow change side, that wil happen within few degrees, tigether with that any contra-torque have to build up - but we at least can counteract the pointing and reduce the consequences.

1): A Guara-steered raft you can point where you want as explained at page #5.
Therefore a quick helmsman can plunge down aft a surplus of guaras, as can move backward the CLR, each time the drag from the one-sided bow wave try to force the raft to sail inclined.

2): A permanent deep aspect keel will reinforce the function of the straight sidetrunks and therefore reduce the 20 degrees - but too reduce the steering effect of each Guara.

3): The skipper too can accept to sail ahead along the diagonal; and that sailing depend only of your sail and rig. You have to adjust this for the conditions of the diagonal, and not the centerline - turn the yard, move fastning of both tack and sheet.

4): The last choice is to change the fatal square-off bow: take a saw and cut the wooden trunks in pointed shape or mount a "snow-plough" as Thor Heyerdahl did, as can divide the incomming waves in two equal streams.


[ img - scout+box-kite.jpg ]
A raft with length /beam relation 3:1 - as well as a box-kite with same geometric side relation and the kite with the string tied in a corner-stick - will tumble a little less than 20 degrees to stay stable (try it yourself)
That means, that such a square-off raft is born with a "leeway" of 20 degrees, and with wind abeam the raft will turn her pointing even more to counteract the lateral-wind press with an increased water press on lee bow and side.
That phenomenon is the mother of all LEEWAY - and that is why a sail-vessel always seems pointing higher to the wind than the thrue course.

More common we can say, that a craft - and therefor too a raft - will try to sail along the centerline - at least as long as she has a stem as can hit and split the water before any corner do it.

The minimum angle for the bow can be calculated. With l/w=3:1, geometrically the angel of diagonal to centerline is near 20 degrees, therefor the bow angel should be sharper than 140 degrees to let the stem hit the water befor a shoulder and in that way ensure the course-neutral phenomenon of water-press on both sides of bow.
And that is the message to use for next experimental raft-raid.

A square-off raft will flip-over and change direction within few degrees

[ img - afdrift+styret-Kurs-C.png ]
the first raft wil correct her pointing - the other not, she will stay

What we try to explain with a sketch of the water streems against the bows of two comparable rafts is:
A raft with pointed bow, immediately will try to correct to the pointed course by applying more water-press on lee bow and side
- whereas a square-off bow first will find the balance, when the raft has passed the diagonal and the press from streaming water on lee side is equal with the press on the square-off bow.

Rule for square-off Guara-rafts:
Any Guara-raft you can point as you will
but a square-off raft could need a reinforced keel-system
to counteract the flipflop phenomenon from the one-sided bow wave when changing side

A more relaxed explication:
Sailing ahead the stem is pressed into the sea and of this reason hindered in side-sliding - whereas the water is slipping the aft end without hinder nothing there.
That have as consequence that the dynamic part of the hydraulic resistance will move CLR = the common hydraulic centre ahead. But either that is a greater problem, because we can move around our Hydraulic Centre as we will by plunging in more or lifting up Guaras - and in that way compensate.

Centerline sailing with a square-off raft is NOT recommended.
That means that we can point our square raft statically for sailing along the centerline, and if our sail is adjusted for that, we will sail - but as demonstrated at these pages, even if we can balance, compensate and limit the square-off bow phenomenon, the centerline isn't specially stable as sail-direction neither directly downwind. The flip-over effect of the bowwave changing side will will be triggered brusquely, and the helmsman has to be very quick to counteract. He will need a constant activity with the Guaras to keep on sailing along a centerline pointing.

In all cases the sail has to be adjusted for the real sail-direction, and if the sail is adjusted carefully for this - we will sail. If not, we will have a problem!

A little mathematic exercise.
A square-rigged boat has a rather large 'no-go' zone, but we know that a normal square-rigged craft at least will be able to go 80 degrees to the wind. In this norse case the diagonal hold 20 degrees to the centerline of the hull, so if we subtract or add 20 degrees to the 80 degrees, we get respectively 60 degrees and 100 degrees. 60 degrees is difficult for a square-rigger to reach, but 100 degrees was what we got - and that is what we can read from the photo.

100˚ to the wind is in contrast to what the old chroniclers told us: the Inca Rafts could sail out and come back to same place on the coast; but we don't know if any of the post-Heyerdahl replica-rafts was able to do that.

We have to analyse the sail !


Square sail rigging on square-off raft

[ img - Compass_Rose.png ]
The common rule for a Guara raft:
You can control the pointing of your raft all the Compass around - with your Guaras alone
and the Center of Wind will blow to lee of the Center of Water Resistance

- if the sail is adjusted for the now pointed course, you are sailing -

And here is where the Norwegian raft design went wrong 2015

[ img - howTo.png ]
Note: - On board any craft it is how the vessel meet the elements, as define the adjustment of sails.
That means: true course and apparent wind - - - NEITHER pointed course, NOR centerline - NOR true wind

The square sail.
A lonely square sail has not many options to move around with the wind-center. With push or lift in sail that CE-center is principally the center of the canvas, and the canvas transfer the windforces to the boat by 3 fix-points: the tack, the sheet and the parrel. The parrel has as consequence, that we can swing the sail around the mast and the wind centre will therefor allways stay somewhere on a half-circle - and with that knowledge the rest of pointing must be done by our Guaras. The pointing of boat and the adjustment of sail has to correspond to push our boat ahead - and to find out that, is the art of skipper.

the semicircle of CE = Center of Effort
for a lonely square sail
[ img - sq-raft.png ]

Rule for raft skippers:
To beat higher to the wind, a skipper has two options:
1): move the CLR ahead (the Guaras) - - - or 2): move the CE (the sail-center) backwards
- or both -
In all the cases:
- with wind abeam skipper still has to forsee certain leeway
[ img - sail+hull-A.png ] [ img - sail+hull-B.png ] [ img - sail+hull-C.png ] [ img - sail+hull-D.png ]

1):   static adjusted Guaras for pointing East - without sailing and without the dynamic forward press on CLR
2):   sailing-on, the raft will turn to diagonal sailing - because all water press on transom bow is working unilateral, giving a twist on the raft
3):   this wry pointing can be compensated by mounting a deep-aspect fin-keel or plunging more Guaras down aft.
4):   an alternative could be to move CE forward to match the CLR - by mounting a foresail or a jib in the stay
 
 
A more pragmatic explication:
Sailing ahead, a hull is pressing her stem and bow into the water - whereas the water is slipping astern. That has as consequence, that sailing with a wind abeam - the wind as will try to move ALL the craft sideways, but will mostly be able move the stern. That is due to the prow as is kept fixed by the pressing water - while astern the water is streaming away from hull with a very little hinder of anything.
Result: The Center of Water Resistance has moved forward, giving the ship weather helm, and we have to rely on our Guaras. As explained earlier: sidesliding of for and aft on a raft with Guaras we can controll individually.

And this moving ahead of CLR is perhaps the reason, why newer speedy sails-ships seems to carry rather much sails in front of the hull + eventually equiped with foresail, bowsprit and jibs - and too have rather much skeg and keel aft - as the famous Bluenose from Newfoundland - the "Queen of the North Atlantic".   [ img - bluenose.jpg]     [ img - canadian10.png ]


The study of air-photo continued.
The yard is braced 60˚ to centerline = 80˚ to sailed course - The sail seems adjusted fair for a wind abeam and for sailing along the centerline of the craft.
In this case the raft is NOT sailing along any centerline, she is sailing along a diagonal - and consequently the sail has to be adjusted for the diagonal.

The center of wind is for all practical purpose the center of sail in sailing position, and there is not considered any important lift in the actual position more than compensated by wind on hut. The center of this sail is the letter R in 'Heyerdahl'. That center is placed over the starboard gunwale of raft, as indicated at foto by a red 4-star - and that can only be moved swinging in a circle around the mast.
The sailed course is along the diagonal, and therefor the hydraulic center of resistance must be placed somewhere on the same blue diagonal.
The flag indicate a wind directly abeam, and therefor the hydraulic center need to be directly upwind of the Center of Wind - and must therefor be where indicated with a blue 5-star.
The mast is raised on crossbeam #5, as indicated by black crossing lines - and the fulcrum of the center of sail, must be in between the blach cross as indicate the foot of mast and its parrel of the yard. The parrel is the pivot, as the yard is swinging around.
Nevertheless the sail seems rather baggy, and it is uncertain how high to the wind this shape will permit - my guess is arround 80 degrees, and not much more.

First try - move CLR forward - negative.
We are actually sailing 110 degrees to the wind, and to change the pointing to 80˚ we need to luff 30˚ up against wind.
That we can do easy. By correcting the pointing we simply can move the the Hydraulic Center (CLR) more forward, by push down more Guaras in front or lift up aft in stern, and subsequently the wind will blow its own center leeward to the this new CLR.
"and if the sail is adjusted for the pointed course, you are sailing", the rule says - but that we aren't - we have got out of range of the sail!
We will not sail forward, at least!
In this case the sail will loose the wind on backside as fill the canvas and blow up the cambered profile. We will get backwind, the sail will collapse and the Center of Wind will move in some way, as probobly will turn up the bow directly against the wind.

A desktop exercise:

(a play with adjustment of the sail as it was, but with all reservation for the point of view and angel of perspective).
situation BEFORE
[ img - Raft-not-turned.png ]
schematic analysis
[ img - yard.png ]
situation AFTER
[ img - raft-turned.png ]
Only step on a drawing is to brace the sail with its Center of Wind 40˚ more around the mast (too move tack, cleat and fastenings)
- then let the Northern wind blow the new Center of Wind to lee of the old Center of Water Resistance

Result: the raft correct her course around 30˚ closer to wind.
As second result the yard (colored olive) now seems to divide more correct the angel between wind and sailed course - yielding more propulsion.

[ img - sq-raft3 .png ]

Repeated NOTE:    that is the angel between apparent wind and true course of boat, the skipper have to pay heed to
- and therefore the pointing of his flag and the diagonal sailing of his raft -

Second try - move backward CE - better.(the desktop excercise)
Otherwise. If instead of manipulate the Guaras we brace the yard 40˚ nearer to centerline plus move tack and sheet to new positions, then the wind-centre will swing with center on mast to a new position more against aft (on the photo the fulcrum of the sail is a point between mast foot and parrel).
Subsequently the wind will blow this new Center of Wind to lee of the old hydraulic centre, as we haven't tuched, and as result her pointing is corrected around the 30˚ - just as we wanted.
With that the raft will go on sailing along her diagonal, but this time hopefully 80˚ to the wind, which is much better and at least against the wind.
30˚ luff up could create a conflict between the canvas and the forestay. If so, you then have to accept the deformation of the aerodynamic profile and reduction of lift - or you have to change something on the forestay. As I remember the raft Tupac Amaru, she had two forestays, so something could be done - too at sea.

Try even harder and better.
If the actual sail with this rather blunt edge profile, can do even more, then try it. Perhaps with 10 degrees more pointing = 70 degrees to wind. This depend mostly of the shape of sail. The sail unfortunately have got shrinked its boltrope and therefor lost its sharp cutting edge, but to correct that, is a larger operation with needles and yarn. But OK - the sail was bought in Poland for "a good price". Nevertheless, too the old sail from Tangaroa2 -2006 was on board as reserve, and it could have been tried out, even if some known old photos not indicate much better shape.     [ img - tangaroa2_sea.jpg ]       [ img - tangaroa2.jpg ]

The disadvantage
The awkward sailing along a diagonal is OK, as a mend for a faulty hull design, but that make it more complicated, when you have to go-about and change over to sail along the other diagonal. But neither this is important, beeing a manouvre you don't need so often on open ocean. The important is to be able to beat against the wind.

even with bow-line set, the boltrope has shrinked and crimpled the cutting edge
- furthermore the camber is deformed by the stay, which is difficulting lift from a sweeping wind over upper part of the sail
[ img - shrinken-boltrope.jpg ] [ img - deformed-camber.png ]
[ img - havhingst3.jpg ]
example of a correct shaped sail:
- no deformation of canvas nor leech
- bowline tight
- wind-cutting leech sharp
- rather flat camber

Result: 58˚ to wind

Conclusion of sails.
With this analysis it seems as the Norwegians had imported a pure Nordlandsrig with tack, cleat and fastenings, where they in hundreds of years had been placed on a classic Nordlands jekta - without to take in account, that in this case they had changed drastic the hull shape of their vessels.
All this is pure hypothesis, as we still miss to verify - but the rafts have got lost in South Pacific.


Seamanship

That is not the purpose for a sail manual to judge crew and seamanship. Our task is to analyze what happened, point out solutions, explain and in that way teach next skipper how to combat such problems.

That was perhaps an ill-considered idea and a silly fault to change a well-proved hull shape, but the fatal and decisive arised in the moment they in their eager to start their Heyerdahl-adventure, against all their Norwegian traditions pushed aside every final test and trial of their new ship-construction before sailing out on a monthlong raid. The well established "prøveseglingsprosdyre" = 'procedure of test sailing' described by Jon Godal, they left out.

The two rafts sailed along a diagonal, and that was what the crew should have seen on a test-sailing - and adjusted both rafts for that.

If provoking the Gods, then they make their Nemesis follow your Hubris

The unexpected result:
The archaeological purpose was beforehand rather vague. We had felt much doubt around the scientific value this Kontiki2-raid, but here the great surprise showed up: they verified - certainly unintended and by a self-sacrificial action - that the rafts in South America by the many hundred of years development had been so well optimized, that they have given us a useful hull shape for oceangoing balsa rafts, as not easily can be done better: The pointed prow, the long slab sideline - and a steering controlled by Guaras /daggerboards.


What could they have done
to escape the sad ending ?

Nevertheless
- perhaps NEXT Norse raid will show more loyalty to the authentic South American culture
- and less freebooter -
The occurrence of 'el Niño' they couldn't change; but they could have chosen another time of the year, knowing from Inca-time, that sailing to Easter Island was impossible or at least difficult from November to March.
They knew it, calculated the risk and took the chance.

But on their way to Easter Island they learned the fatal tacking capacity of their rafts, and therefor they in the harbour of Hangaroa had three options:
#1): They could have waited for better wind, waited patiently just as the oldtimer sailors often did.

#2): They could have recognized that their crafts of some reasons prefered to sail along a diagonal.
Knowing that a sail has to be adjusted in relation to how the craft meet the elements of water and of wind: the sail has to split up and divide the angel between apparent wind and sailed course and not pointed course. Therefor it could be an idea if the skipper changed the rigging to follow that. 20 degrees out of center line seems to be an operation as could be possible to carry out on the sea by change the fixation points for tack and for sheet and perhaps move a forestay out of touch with the yard.

#3): Alternatively they in Hangaroa could have changed the shape of the bow of their rafts (and tested the changes) before sailing out on last leg - and in that way eliminate the tendency to flip over to diagonal sailing, and escape the main reason for the missing ability to beat against wind.
What they would have needed for the operation, was only a good saw, for cutting off the timbers and reshape a prow.
Perhaps they too could have moved their mast more ahead (as the Humber keel) - to counteract the effect of a transom stem.

None of these three proposals are possible to re-examine and verify. The rafts have vanished and no report is published.
= as a posthumous diagnosis, where the carcass had disappeared.

Kontiki2 tugged out of Callao
[ img - buttnosed.jpg ]
 
[ img - classicRaftShape.gif ]
[ img - balsa+pointed-prow.gif ]
A surprise because they missed a start-check
[ img - actual-prow.jpg ]
Possible corrections for raft shape - as could have saved the raid:
Cutting in Inca-maner by stepping down the trunks - or cutting slanted to shape a prow for the raft
- or perhaps adjusted this Norwegian square-sail rigging to the real sail direction - the diagonal


Rule for Guara-rafts:
If a raft can't beat to wind it is NOT a Guara-problem
- the problem is either the hull, the sail or missing seamanship -

trefork2.png   Conclusion   trefork2R.png

The Hull:   The Inca hull was clearly changed, had got the prow amputated and was now more as a square floating board - with two stems
The Sail:   The rigging was the well known Nordland square rig, as was adjusted for centerline sailing, and not for the real diagonal heading.
The Seamanship:
They sailed out without any test of their new craft - and that was bad.
They sailed with a baggy sail accepting the poor low yield of their raft, and knowing that a baggy sail will not be able to beat high to the wind
(- and we have not even heard, if they have tried out their reserve sail from their old Tangaroa2 raft of 2006).
They left last port without having corrected anything of what obvious was faulty - neither on hull nor rigging.
They resigned to their fate, relying on their luck and the cold east-going tradewinds further south, where no South American never have sailed with a wash-through raft.

The rafts were by an error constructed to sail along a diagonal.
Therefor the sail should have been adjusted for this - and not adjusted for centerline sailing.

Note:
In all relations in the life that is your result as count - and not your promise nor your intentions.
This rule is valid in all case of life - too for rafters:
Did you make it - or did you not?

Fate of later oceangoing log Rafts

[ img - THI-logo8.png ]

Science
Pseudoscience
Adventure
or Survival

In the last 100 years 20 rafts inclusive Kon-tiki sailed out on the Pacific Ocean.
The 8 complied and reached their destination, and the reminder 12 rafts was Lost.
Of these 12 at least 6 ware sunken by Teredo Navalis

#1 - Kon-Tiki
1947 Thor Heyerdahl with his 5 scandinavian mates made the first adventurous raft voyage after the dark years of the World War
Result: Raft raid completed - if the trunks were tarred, we don't know.

#2 - Seven Little Sisters
1954 William Willis sailed singlehanded on his raft Seven Little Sisters from Peru to American Samoa, and completed successfully the journey. He sailed 6,700 miles, which was 2,200 miles farther than Kon-Tiki.
Result: Raft raid completed.

1963 in a second great voyage ten years later, William Willis rafted 11,000 miles from South America to Australia with a metal bodied raft ‘Age Unlimited'. The raid was completed but is not counted as a wooden log-raft.

#3 - La Kantuta
1955 the Czech explorer and adventurer Eduard Ingris attempted to recreate the Kon-Tiki expedition on a balsa raft called Kantuta. This first expedition, Kantuta led to failure.
Result: The raft lost how?

#4 - Tahiti-Nui
1956 the famous French seafarer, Eric de Bisschop, committed himself in a project he have had for some years: he built a Polynesian raft in order to cross the eastern Pacific Ocean from Tahiti to Chile (contrary to Thor Heyerdahl's crossing); the Tahiti-Nui left Papeete with a crew of five. When near the Juan Fernández Islands (Chile) 6 months later, the raft was in a very poor state due to an infestation of the clam Teredo Navalis, and they asked the Chilenean Navy for a towing, but the Tahiti-Nui was damaged during the operation and had to be abandoned. They were able to save a part of their equipment on board.
Result: Raft lost due to Teredo Navalis

#5 - Tahiti-Nui II
1958 Eric de Bisschop build a second Tahiti-Nui from Cypres-logs in Constitución, Chile; in April they left towards Callao, then turning towards the Marquesas, but they missed their target, and after four months at sea, too this raft began to sink due to the same Teredo Navalis.
Result: Raft lost due to teredo Navalis.

#6 - Tahiti-Nui III
The raft was build out in the ocean by the more buoyant parts of Tahiti Nui II and this new and smaller raft were swept along towards Cook Islands, but went aground and was wrecked at Rakahanga atoll on August 30. Eric de Bisschop was the only person who died in this accident. A death as this great sailor probably self would have taken, if he have had the choice. Ref. Book: From Raft to Raft, by Bengt Danielsson.
Result: Raft lost due to Shipwreck.

#7 - La Kantuta II
In 1959 Eduard Ingris built a new balsa raft, Kantuta II, and tried to repeat his previous expedition. This second expedition was a success. Ingris was able to cross the Pacific Ocean on the balsa raft from Peru to Polynesia.
Result: The Raft raid completed - no more information given

#8 - Tangaroa
1965 Being Peruvian citizen Carlos Caravedo Arca was a natural victim to be trapped by latin bureaucracy, and of incomprehensible reasons the authorities wouldn't give leave for departure.
At last a permision to sail-off was promised against taking on board a friend of the port authorities - a pilot and his assistant. With 4 months spent on waiting, while his balsa raft got more and more waterlogged, Carlos Caravedra of course accepted, and they sailed off from Callao.
Even if a such composed team wasn't the world's best, the three men were able to sail together, and they crossed the Pacific Ocean in 115 days, of which the 18 last days were used to pass the dangerous Tuamotu Archipelago of French Polynesia by its own means.
Tangaroa ended its Pacific crossing on the Fakarava Island, where the raft was donated to the local community - and the men parted.
Result: Raft raid completed - no documentation published.
Note: The trunks were treated with raw oil spiced with poison - Limited attack by Teredo Navalis.

#9 - La Pacifica
1966 The Spaniard Vital Alsar boarded a simple raft, La Pacífica, intended to cover the route between Ecuador and Australia. This journey was cut short by a severe Teredo Navalis attack in the wood of his raft. The raft sank after 143 days of navigation, and the lonely captain was rescued by a German ship.
Result: Raft lost due to Teredo Navalis.

#10 - La Balsa
1970 The second raft of Vital Alzar, La Balsa featured by a balsa wood and hemp rope built structure, to which was attached two hardwood masts, to support a square sail. In contrast to the oar used for steering on Kon-Tiki, the La Balsa was equipped with a hardwood daggerboards (known as Guaras in Ecuador) which allowed it to be actively sailed toward favourable currents, rather than drifting.
The La Balsa expedition lasted 160 days, starting in Ecuador on May 29, 1970, and ended at Mooloolaba in Australia on November 5, 1970.
Alzar had recruited a Frenchman and a Canadian, and with work already begun they were later joined by Chilean student Gabriel Salas (only three companions). The crossing was successful. The 8,600 mile voyage was, at the time, the longest in known history.
La Balsa have 1970 not left any report around their conditions nor their experimental archaeological results.
Result: The raid completed - raft partial tarred

#11, #12 + #13 - Guayaquil, Mooloolaba and Aztlan = Expedition 'Las Tres Balsas'
1973 Las Balsas expedition was the first multiple-raft crossing of the Pacific Ocean in recent history. This expedition too was led by the Spaniard Vital Alsar, who in 1970 had led the ‘La Balsa' expedition - and 1966 La Pacifica.
The three rafts was 14 metres classic Ecuadorian design and each with a crew of 4. The purpose of this 1973 expedition was three-fold: 1): to prove that the success of 1970 was no accident, 2): to test different currents in the sea, which Alsar maintained that ancient mariners knew in same way as modern humans know a road maps, and 3): to show that the original expeditions, directed toward trade or colonisation, may have consisted of small fleets of balsa rafts.
Two of the three rafts reached Australia - the ‘Guayaquil' raft was lost in a storm. The expedition is the longest-known raft voyage in recent history. With 9,000 miles (14,000 km) and 179 days of duration this expedition eclipsed the earlier of ‘La Balsa'.
Result: Two raft raids completed and one raft was lost
- the rafts were partly tarred and all partly eaten by Teredo Navalis (ref: John Haslett's book The Lost Rafts p. 286)

#14 - 1995 Illa Tiki
1995 John Haslett build a copy of Kon-tiki and sailed it to Panama - here the raft was abandoned destroyed by the ship-worm Teredo Navalis. The raft could have been saved by modern chemicals, but then it would not any more be a worthy archaeological experiment.
Result: Raft lost due to Teredo Navalis.

#15, #16 + #17 - Manteña Huancavilca + Manteña Huancavilca II + La Endurancia
1998 John Haslett tried again, and as continuation of Illa-Tiki he build a rather big raft (20 metres) equipped with two masts and lateen sails and set off from Ecuador bound for Mexico - and with aim to go further on. This raft too was attacked by the Shipworm Teredo Navalis and was losing buoyancy and sailed to Colombia to be repaired with new logs
- 1998 this second was caught by circular currents in the doldrums where it circled around in ring more than two months, but was again infested by Shipworms and was abandoned on sea.
A third raft La Endurancia was in 1999 build in Costa Rica to replace the lost ones, but under a storm in the beginning of their raid it was thrown on the rocks and destroyed.
Book: The lost Raft, by John Haslett and Cameron Smith
Result: two rafts lost to Teredo Navalis + one lost by shipwreck - the rafts were partly tarred

#18 - Tangaroa-II
2006 was repeated the Kon-Tiki experience using a newly built raft, with the name Tangaroa, name of the Maori sea-god Tangaroa. The six-man crew was led by Norwegian Torgeir Higraff and perhaps most important included a grandson of Thor Heyerdahl - Olav Heyerdahl + the Norwegians Bjarne Krekvik and Øyvin Lauten, Swedish Anders Berg and peruvian Roberto Sala. Tangaroa-II was launched on the same day as Kon-Tiki had been 59 years earlier - 28 of April - and it reached its destination oin July, which was 30 days faster than Heyerdahl's result. Kon-Tiki had taken 101 days for the voyage. The speed of Tangaroa they credited to the proper use of Guaras (daggerboards), but with wind mainly from aft, the higher speed probably was more due to the bigger hull and the much bigger sail.
Tangaroa-2 have not left any evidence nor report around Guara-navigating neither nothing around other archaeological matter. It looks more like pure adventure or propaganda-trip.
Result: The raft raid completed - the rafts was partly tarred
The Tangaroa-2 raft was brought to Norway and later recycled as raw material for a Kon-tiki replica, as entered in the scenery for a new film around the Kon-tiki voyage of Thor Heyerdahl

#19 + #20 - Rapa Nui and Tupac Yupanki = Kontiki-2 expedition
2015 Torgeir Higraff build two new rafts as departed from Callao navy shipyard with intentions to sail to Easter Island - turn around the island and go back to their starting point Callao. They reached Eater Island without greater problems blown by wind mainly from behind. On their return they were drifted west and south and after 10 weeks on sea they abandoned their rafts still far away from South America. The cause for this disaster is described earlier on this site.
Archaeological Lesson: A hull shape developed on base of hundreds of years experience is not easily transformed to other shape without reprisals from sea deities: Ægir, Njord, Poseidon or Neptunus.
No report is still not published around Kontiki2 expedition - nor any archaeological result.
Result: Both rafts were abandonned in open sea by their crews
Both rafts was partly tarred - no evidence about attack of Teredo Navalis


Thankyou for your deed!

We want here to express our deep gratefulness to the two authors and raft-skippers: Thor Heyerdahl on his Kontiki-1947 and John Haslett with his Illa Tiki + Manteño Huancavilca rafts 1994-98
Thanks for their carefully written accounts of their raft-raids in the Pacific.

- even if we still are waiting for the rest of the twenty raft-sailings, we have to recognize, that a great part of those accounts probably never will be written -


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Lima - November 2017