Text written in March 99, after the race Around Alone 98-99

60 ’ Open, the conditions of safety, past evolution, current state, future

 

1 - The safety is the problem n°1
            A - Integrity of the hull
            B - Integrity of the ballast
            C - Stability of the boat
                        In Normal Progress
                        Sufficient to resist to the waves
                        Right the overturned boat
            D - The resistance to the charging
            E - The integrity of the rigging
            F - The integrity of rudder
            G - Well control the boat
            H - Go fast
            I - The comfort		 2 - The efficiency of the boat

3 - Evolution of our 60 ’ open on the safety
            1-st Vendee Globe
            3 rd Boc Challenge cup
            2 nd Vendee Globe
            4 th Boc Challenge cup
            3 rd Vendee Globe
           5 th Around Alone

4 - Our wish for the future

 

For 10 years - our first 60 feet Open dates indeed from 1989 - using the progresses of the techniques of construction, we gradually improved the solidity, the stability and the speed of these boats.
5 years ago, when we conceived the Geodis's and PRB's generation, we were not able to (as many other colleagues, runners, organizers) anticipate this type of accident due to in the muddled seas or in the more and more intensive configurations of use.
Following Vendee Globe 96-97, many actors met (architects, runners, organizers, assistants) and decided to increase the stability and  straightenability of the boats. It was made on all the new boats for 2 years.
For the former boats, PRB in particular, immediate measures were decided to apply and others to apply as fast as possible (increase of the stability, means of straightenability).

In the light of all the previous accidents, the solidity of hull (the most numerous) and stability, it is advisable indeed to analyze the problems to try to avoid that they reproduce and to take the necessary measures in common, architect, runners, organizers.
It is not already easy to draw the lessons from the known problems, it is much more difficult to anticipate the problems and to take the corresponding measures.
At present, moreover, we are even more worried than previously for the 60 ’ because the level of the competition increases, the use of the boats evolves enormously.
As architects, we try to become aware of limits of the boats and to communicate these limits so that the race stays in a some context of safety.
This context  must be decided during a serene debate which leads to consensual decisions taken with all the actors.

 

Which have to be objectives of the 60’ Open ?

Sail around the world with the minimum of problems and for the greatest pleasure of the runner. For that, it is necessary :

  • That the runner returns healthy
  • That the boat returns in good condition
  • That the boat goes fast, right, easily

 

 

1) The safety is the problem n°1

This safety is a function of factors of different importance

A) The integrity of the hull

Indispensable qualities to protect the runner
  • The integrity of the hull
  • Unsinkable hull
  • The integrity of the keel fin
 It must be able to live on the right and over boat, so it is required:
  • watertight partitions
  • the possibility of crossing from one of a compartment to another
  • the possibility of  taking out of the boat in the two positions
At any speed of the boat and for any kind of common object met, the hull and the deck have to be able to resist to the assaults of the sea and to the efforts due to this speed which is more and more important : the boat must keep its integrity so that the runner can put on it without reservation.

Plan

 

B) The integrity of the ballast

The ballast must not fall down...
We can not speak about the boat's progress and the stability if the solidity of the ballast and its control are not mastered.
The bulb, the keel fin, the systems of control have to be able to support the accelerations of the sea as well as some little violent occasional grounding.
Until now, the speed considerated for the calculation of the grounding was 10 knots.
The essential points to maintain the integrity of the ballast are :

 

  • the hanging of the bulb
  • the solidity of the fin during bending and  torsion
  • the hanging of the ballast in the hull
  • the solidity of the ring frames
  • the bonds of the ring frames on the general structure of the boat
  • the axis of suspension of the keel
  • the landings of fixation of the keel on the hull
  • the fixing of the jacks on the keel
  • the solidity of the jacks
  • the holding of the jacks on the hull
  • the good geometry of the axes so that the rotation does without problem
  • the good reliability of the hydraulics
  • a redundancy in the hydraulic system
All these points are as the links of a chain, if one of them fails in its role, the keel has not more effect. It can not only disappear or, worse, provoke the total loss of the boat.

Plan

C) The stability of the boat

The absolute stability must allow the good progress of the rigged boat:
  • the boat lies down not too fast
  • the mast, if it comes to touch the water, does not make it too fast and is not broken
  • if the boat is rolled, it returns over right in its natural position.
 These different objectives are obtained thanks to:
  • A centre of gravity low enough
  • Water ballasts
  • The slope of the ballast
  • The moving of the tools inside
 

When the boat lies by the wind or by the centrifugal force in any movement of rotation, the boat must be able to get up whereas it is lying flat on the water and whereas the wind is pushing on the vertical hull which is windage.

So it is necessary to have, in that case, a sufficient stability to get up. This stability is expressed by a GZ curve at 90°, which means the distance between the centre of hull and the centre of gravity.

This measure must be taken in the condition of rating but also in the condition of navigation with the most unfavourable configuration (filled water ballasts, oblique keel).

b- the sufficient stability to resist to the waves

When the boat is pushed by a wave, a certain energy must be spent to roll it completely.
For the regulations, this energy minimum to make turn over the boat is translated by an angle of theoretical capsize. At present, for the most commun scenarios, a consensual agreement seems gradually to be decided on 125° of angle of theoretical capsize, whish gives a correct safety.
If the boat is rolled, it is upside down. To bring it back right again, it is necessary to tilt it again of 50° compared to this upside position.

As comparison, the stability of a "vaurien" (the famous little boat)  in right normal position  is 50°.
Scenario n°1

If the boat is put upside down by important, regular and insistent waves, the necessary energy to right the boat is clearly lower than the one that was necessary to turn it over.

The ratio of these energies is from 4 to 1 (accepted value at present as the 125 °).

These figures are always very discussed and it is possible that in the future, we are obliged to raise them.

 Scenario n°2

If the boat was turnd over by a occasional wave, it will not find necessarily again an equivalent occasional wave to right it again.

The occasional waves occur generally in the end of the bad weather, in the crossed swells.
It was the scenario of  the accident of Thierry Dubois in Vendee Globe 96-97. The boat were twice turned over in series of waves in bad weather, it returned right thanks to the  following waves. Then it  was capsized by a last wave and no other important enough occasional wave was able to bring it back right.
 

Scenario n°3

Another scenario can exist in the following configurations:
  • moderate waves
  • an important speed
  • sails up
  • ballast and water ballast in bad position
 with the conjunction :
      - inertia of rotation of the boat,
      - natural inclination of the waves before that they unfurl (17°),        - movement of the water in these same waves,
the boat can upside down and not be able to return because of  the stress of the sea.

c-Right the overturned boat

It is so necessary to find a reliable system to bring back the boat right  in every case of figure.
Solutions :

c-1 the invasion of compartments (this system is very alarming for the skipper already in a difficult situation).
The voluntary invasion of the bow's compartments offers the possibility of a straightening. The quantity of water to put in (10 - 16 m 3 ) is not negligible. This solution is delicate : the behavior of the straightened boat is worrisome (trim, very decreased pounding on, decreased resistance to the shocks of the waves ) Envcompenvahispe. gif (13000 octets)
60 feet's trim.  Invaded compartments before straightening
c-2) basculement of the ballast

c-3) very important superstructures (with a small width).

The very important permanent superstructure is a handicap for the good progress of  the boat by its windage, the position of the centre of gravity, the complication for the operations. Smaller width gives a more heeled boat  which lies easily, and the life and the operations are more difficult and more dangerous.
c-4) inflation of a temporary superstructure (airbag)
Envairbagpe. gif (on 7045 octets)  

The solution of an airbag, paticularly for the boats with fixed keel, allows to recreate temporarily a superstructure of an important volume which allows to right the overturned boat. The airbag weighs 60 to 100 kg. It is constituted of a cylindrical balloon of  2 m by 2, folded up in a container in the centre of stern deck.

This balloon can be inflated from the inside of the boat (various methods: pump by hand, electric pump, a reserve of compressed air or mixture of compressed air and of gas produced by pyrotechnics). The webbing of the balloon is always at its post and tightens in the inflating. The system must be re-used and be able to be folded up by inhalation. This system, if it is effectively inflated, provide the straightening of the boat even in smooth sea. Airbagpe. gif (10032 octets)
Plan

D) The resistance to the charging

The strength of the wind, the speed of the boat, the descent in the waves are aimed at digging in the boat.
This can have the effect of  flooding the deck or causing a reversal of the boat.
The shapes in the bow, in particular the topsides of the hull, have big importance because the purpose is to go out above the waves.
This capacity of the boat to lift up itself is often in contradiction with the good   speed tacking in a choppy sea where it is rather necessary to cross the waves. 

E) The integrity of the rigging

The rigging must be able to resist

  • to the stress of the sails compensated by the stability of the boat
  • to its own inertia when the sea shakes or stops the boat (when it taps in the waves)
  • to the wrong operations
  • when the boat lies on the water and that the mast comes to strike the water
  • to the hydrodynamic stress which apply to it when the boat is rolled
  • to the hydrostatic pressure of the water which, to 25 m of depth, is 2,5 bars to vibrations
  • to the fatigue
  • to the cold
  • to the occasional shocks in the ports
  • to the occasional mooring of the neighbour who hangs on a bottlescrew.
One or several rudders have to resist :
  • to the hydrostatic pressure due to its incidence and the speed
  • to the stress of the sea which breaks out and which pushes the rudder in the other direction from the aft
  • to the shocks of the floating objects.
 The stress due to the sea are normal, the rudders have to be enough sampled.

It is not necessarily physically possible to resist to the floating objects .
 

The rudder can be protected by covering up it or by having a rudder of help as well PRB demonstrated  in the second leg of Around Alone.

Plan

G) Well control the boat

It is obtained thanks to :

  • a good balance of the hull while heeling. It supposes a slightly symmetric bottom, so fed in bow, what participate in the resistance to the charging, but with its handicaps in chop.
  • the rudder and  the automatic pilot, that have to allow the boat always to go straight, in the best cases to keep always the control, and compensate for the imbalance due to the sails.

    • In crew, one can act simultaneously on the sails and on the rudder to maintain the global balance of the boat. Solo, it is necessary that the automatic pilot alone can maintain this global balance.

  • a good adjustment of the sails.
    The operations and the adjustment of the sails must be made with the minimum of tiredness and the maximum of safety to adapt the better type of sail and their good surface to the strength and to the point of sail.

It depends on:

  • the disposal of the sail plan
  • the distribution of the sails
  • the systems of rolling-up
  • the disposal of the cockpit, of winches, of  reef's holds

Plan

H) Go fast to be in the good place at the good moment

Have the ability to go fast is a factor of safety, to take place in the best place compared to the depressions, have the good wind and few waves. In a serie of waves, it allows well to take place compared to the waves and to have the most effective possible rudder when the boat is joined by the waves.
Faster the boat goes, less chance it will have to be caught up by the waves, less it will be pushed aside, less it will be overtaken by the depressions, less it will undergo them.
On the other hand, this speed must be obtained without danger. The boat must not be faster than the optimum of safety. Beyond, the boat shows signs of strain, the crew gets tired, the boat gets out of control by its speed, by the sails that it have etc.

I) The comfort of the boat
With the speed, the boat becomes more and more uncomfortable : the shocks, the vibrations, the noise, provoke a stress of the crew. A division of the volumes, a suspension of the fittings, the absorbtion of the noise by insulating panels, can improve this comfort.
The heeling, the movements of rhythmic rolling  provokes an important tiredness of the crew. Width of the boat and its stability of shape are a good solution to decrease these movements.

 

The integrity of the hull, the integrity of the ballast, the stability of the boat, the resistance in the charging, the integrity of the rudder, the good control of the boat, being in the good place at the good moment thanks to the ability to go fast, the comfort of the boat, all these factors are elements of safety.

They have a lessening importance but nobody can be completely neglected. It is necessary to find the best balance between all these contradictory factors.

The problem of balance of the boat and the choices to decide are not  simple even in the research of an optimum of safety.

2) The efficiency of the boat

To these problems of safety,  may be added the problems of sports efficiency of the boat, which must complete the race around the world with a very limited crew, most quickly possible.
The interest of 60 ’ open is the following one :

  • the length is determined
  • the framework of safety must be determined
  • all the other solutions are free to conceive the most effective possible boat

This framework allows to get ahead with the technology, to find new arrangements, new technical solutions for the sail plan, the mast,... new techniques of construction …
These boats, simple of use, foreshadow the boats that the sailors of tomorrow will want to get , regardless of comfort.

Plan

3) Evolution of our 60 ’ Open on the security

The improvement of the conception of our 60 ’ results from the experience of these races and of the improvement of the techniques of construction. Increasing the solidity and the stability was a constant for the Groupe Finot.
The gain due to the technical progress was distributed between the solidity, the stability and the speed.
 

3 - 1  First Vendée Globe

We draw for Alain Gautier, Générali Concorde, built in aluminum.
The proportions (length, width 5,50-5,80 m, displacement from 13 to 15 ton) are similar to those of Crédit Agricole and of Fleury Michon.
Afterward, this width does not increase.
To lower the centre of gravity at most, we put a bulb, a flat deck, and we much simplify the fitting and the deck. The boat acquires so a little  "hard" characteristic aspect.
The flat deck allows furthermore to maneuver easily. On the other hand, it increases the stability in overturned position if the boat remains watertight.

After the accident of Fleury Michon (that had a GZ from 0 to 90°), Philippe Jeantot surrounds himself with architects.
After inquiry on the existing boats, he notices that the boats have, on average, a displacement of about 14 t and a GZ of 0.3 to 0.5m.
The decision is taken to establish a  GZ minimum of 0.4m for the 2nd Vendée Globe in the best conditions of keel and water ballast.
This GZ of 0,4m corresponds to an angle of capsize, in the best conditions from 105 to 115° according to the proportions of the various boats of this generation.
 

3 - 2  Third Boc Challenge

For Christophe Auguin, we draw  Groupe Sceta, built in stratified sandwich, with a fin of  ballast in stratified.
Shrouds are carried on deck line what allows a lighter mast.
The centre of gravity can so still come down.
On the other hand, we notice in the bow a weakness of the sandwich due to the shocks of the sea.

3 - 3  Second Vendee Globe

For Alain Gautier we draw Bagages Superior.
The hull, in epoxy sandwich, more solid and lighter, and the fin of ballast  in carbon, allow to lower the centre of gravity and to bring the GZ to 0,80 m.
Furthermore the boat is equipped with a waterproof mast.

The departure of the 2 nd Vendee Globe is marked by a lot of problems of hull due to the bad weather in the Bay of Biscay (opened hulls, kicked down bow, failing of the tie of keel).
 

3 - 4  Fourth Boc Challenge

For Christophe Auguin we draw Sceta Calberson-Géodis, built in preimpregnated carbon-nomex.
The solidity of the building material allows to increase the solidity of the boat, to lighten the hull and to lower the centre of gravity with a foreseen GZ of 0,80m.
At this stage, none of our boats until then have known serious problems.

3 - 5  Third Vendée Globe

We draw :

  • Goupe LG for Gerry Roufs, sister-ship of Géodis, in preimpregnated carbon-nomex.
  • PRB for Isabelle Autissier also in carbon-nomex.

    • PRB has a mobile keel with a ballast of 500 kg  heavier than the one of boats with fixed keel. In this way, the foreseen GZ of 90° must remain of 0,8m, even with the oblique keel. In fact, the GZ after measures turned out to be of 0,71m.

    It shows the importance to make real measures, a lot of not controllable factors being able to make divert our forecasts.

  • Aquitaine Innovations for Yves Parlier with an very voluminous orientable mast . Its GZ, at first, is 1 m but it decreases to come down to 0.70m following changes in the rigging.
In the 3 rd Vendée Globe, many tragic elements take place.
Three boats turn over under the effect of the waves : Algimouss of Raphaël Dinelli, Amnesty International of Thierry Dubois and, probably, again under the influence of the waves, one of our realizations, Groupe LG of Gerry Roufs, disappears.
Two other boats lose their ballast and turn over : those of  Tony Bullimore and of Bertrand De Broc.

The architects meet numerous times, with the runners within the framework of the IMOCA, and with the organizers ORC,  FICO, FFV, Vendée Globe.
On the various principles, some consensus becomes established.
We organize the conception of the new boats following the most restrictive framework among those proposed.

The Groupe Finot makes lie existing boats (Géodis, Aquitaine Innovations, PRB) to 90° to measure the real stability in the wide angles. That was a first in this type of boat.
These three boats made New York-San francisco in crew afterward without meeting any problem.

3 - 6    5th Around Alone

PRB

The angle of capsize of PRB measured after Vendée Globe is :
  • in the windward side, storm sails and keel in the axis: 116°
  • reaching, storm sails and keel in the axis: 116 °
  • in the windward side, storm sails and keel to winward: 104°
  • reaching, storm sails and keel to winward: 128 ¨
  • in the windward side, all hoisted sails and keel to winward : 100° (main sail, genoa, solent, staysail and genaker)
  • reaching, main sail 1 reef, no genaker,  keel to winward (case of the capsize): 122°

PRB achieved this 3rd Vendée globe by meeting very difficult conditions. In particular those of January 7, 1997 in the Pacific where the waves given by Météo France were at  H/3 = 13 m which means one third of waves are higher than 13m , one in 1000 is higher than 26 m and the established wind between 70 and 80 knots.
Before the Around's Alone departure several studies of straightening were intrigues.
The voluntary invasion of the bow's compartments offers the possibility of a straightening. The quantity of water to put in (10 - 16 m 3 ) is not negligible. This solution is delicate : the behavior of the straightened boat is worrisome (trim, very decreased pounding on, decreased resistance to the shocks of the waves )


The solution of the airbag  was so retained, not bringing supplementary risk.
This solution, light or heavy depending on whish place is chosen competition or safety (60 to 100 kg), consists in the installation of a cylindrical balloon of 2 m by 2 m folded up in a container in the centre of stern deck   behind the cockpit.
  • This balloon can be inflated by the inside of the boat (various methods: pump by hand, electric pump, a reserve of compressed air or mixture of compressed air and of gas produced by pyrotechnics)
  • The webbing of the balloon is always at itts post and tightens in the inflating
  • The system must be re-used and be able to be folded up by inhalation
  • The resistance to punching of the cover must be of the most raised. A double wrapping is possible.

This system, if it is effectively inflated, provide the straightening of the boat even in smooth sea.
Such system had been realized and delivered to Charleston at departure. Delivered late and not corresponding to the conditions of contract, the PRB team there put back the installation.
Isabelle had, after sailing round world (one and half round) more than 50 000 miles in race with this boat, enough experience and faith in it to make this decision. The facts proved the opposite.

Our boats of the former generation, during the 13 races round the world 7 of which without  stopover and 3 New York-San Francisco, had not met all the conditions of wind, of sea, of speed, of sailing plan, of load, of adjustment, of automatic pilot. The fact that there was no accident of this type was not a sufficient proof.

 

Plan

  4) Our wish for the future :

  • having an angle of capsize of 125°
  • having a ratio of surface of stability curve  4/1
  • having a  measured GZ minimum of  90°  in the most unfavourable conditions

These two last points should be verified following the accident of Isabelle, doubtless it will be necessary to make them stronger afterward
  • Demand and test the straightening systems at 180°
  • Ask the architects and the builders to put down in writing the resistances of the elements of the boats and the means to check them
  • That all the actors (runners, organizers, sponsors, architects, builders, assistants) help each other and have more rigour in relation to their own work
 

All these precautions have to become obligations.
Regrettably nobody knows where places itself the reasonable limit.
It evolves in the time at the same time as the use of the boats.
As the impossiblility to do a somersault  is not asked for a car, we only made a test which allows to avoid doing it too often. It must also be required the same for the boat and demand besides that, if somersault there is, the crew is protected (and helped if need be) and that the boat can right itself.
It is advisable to correct the already known problems.
It is necessary to anticipate the cases which can arrive :

  • Their probability
  • The danger that they represent


This attitude will pass inevitably by more drastic decisions. So, in the example of the Marc Gatehouse's boat, that we forbade of race around the world during the last owner's change (for reasons of fatigue, of ageing), if the organisers doesn't oblige this straightening by itself and demand the pieces of evidence, we shall have to inform formally our discord with regard to the participation in race of the incompetent boats to right themselves.

Plan

 

Link towards the Conference made at Southampton, for the ISAF by Jean Marie Finot, on September 15, 1997

 

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