Jimmy Cornell answers questions about Aventura IV’s concept, special features and extra equipment.
Aventura IV is an Exploration 45, a revolutionary long distance cruising yacht built by Garcia Yachting to Jimmy’s own specifications.
Do you regard your new boat as the ideal, or even the perfect cruising boat?
Jimmy Cornell: I need to make clear that the cruising boat that I was pursuing when I conceived my latest Aventura, was never meant to be the “ideal” cruising boat, but just the boat which would come closest to my own ideal. I came to this conclusion after I considered the results of my latest survey on the subject, when I wrote that:
At the end of my latest comprehensive survey on this subject, I was forced to admit that while one boat may be ideal for one sailor, the same boat might be far from ideal, or even unsuitable, for another. However, I do hope that my new Aventura will come close to other’s “ideal” just that it has come to mine.
You have been pursuing this ideal for many years. Could you elaborate on the various surveys you had conducted on this subject among cruising sailors over the years?
Jimmy Cornell: My very first survey on cruising boat design was conducted in 1978 among 50 long distance sailors whom I interviewed in Fiji.
More surveys followed, and I continued to be so interested in this subject and determined to find out what the essential features should be to create such a boat from scratch that in 1986 I questioned the 200 skippers taking part in the first ARC in a comprehensive survey called “The Ideal Cruising Boat”. Not surprisingly the answers varied a lot and I felt that I had ended up even further from my goal than when I started.
I returned to this subject in several subsequent surveys, the two most relevant being the “Global Cruising Survey”, which was the basis of my book World Cruising Essentials (USA) or World Cruising Survey (UK), and the “Voyage Planning Survey”, conducted in 2011, as part of the research for my book, World Voyage Planner.
Therefore, the overall concept of the new Aventura was based not only on my own hard-gained experience, but was also very much influenced by the many useful things that I had learnt from those surveys and from the interaction with hundreds of participants in the rallies I organized.
To reach a solution I tried to marry my own views with the concentrated wisdom of the hundreds of experienced long distance sailors who had generously shared their views on the essential features of an ideal cruising yacht.
Their views differed widely but there was one point on which they all agreed: the choice of a suitable boat for an offshore voyage is of such paramount importance that the final decision should not be taken lightly. Unfortunately many of the current production boats are not really suitable nor well equipped for a long voyage, certainly not for the one I had in mind. Hence my decision to conceive one myself.
The plans and concept of my new boat generated much interest, and I received many questions.
Why aluminium?
Jimmy Cornell: The first Aventura was a strong and well-built GRP boat that survived in 1977 a three hour grounding on a reef on the Caicos Bank with only superficial scratches. She served me perfectly well during my first circumnavigation but for my next boat (launched in 1987) I decided to go for steel mainly because, once again, I was planning to explore some remote places and believed that a metal boat was better suited for such a purpose. Eventually I realized that while metal had indeed been the right choice, the proper maintenance of a steel hull could be a nightmare. Obviously I should have listened to my friend Erick Bouteleux and go for aluminium, as he had done himself.
In the following 13 years Aventura III, an aluminium OVNI 43 (launched in1998), took me all over the world, including Antarctica and Alaska, and I became totally converted to this wonderful material. One of the greatest advantages of aluminium over any other boat building material is that aluminium naturally forms a thin but durable oxide layer on the exposed surface that prevents further oxidation. Aluminium oxide is impermeable and, unlike the oxide layers on many other metals, it adheres strongly to the parent metal. If damaged, this oxide layer repairs itself immediately.
I must point out that Aventura’s hull, and any other “aluminium” hull, is not made of pure aluminium, but an alloy. Those used in boat construction contain magnesium, such alloys having excellent durability in seawater.
Why an unpainted hull?
Jimmy Cornell: As on my previous boat, my main priority was not only to have a strong boat but also a functional one, and, in my view, nothing can be more functional and maintenance free than an unpainted hull.
One of the great advantages of an unpainted aluminium hull, especially for those of us who do not buy a boat to sit in a marina but to be out sailing, is that you can forget worrying about your gleaming topsides. As most owners will surely agree, those beautiful topsides can be such a worry when confronted with rough docks, barnacle covered pilings, or being boarded by uncaring officials who often come alongside with their launch banging into your hull without any fenders.
While in Antarctica, colliding with bits of ice was practically unavoidable, and while we ended up without any scratches, friends of ours on two fibreglass boats fared much worse.
Why centerboard?
Jimmy Cornell: Why indeed? One of the first questions everyone asks me is how safe it is to sail on a boat without a keel. Having sailed twice across the Drake Passage to Antarctica, both times on a centreboard boat, and having experienced on at least two occasions winds around 60 knots, with swell to match, was a perfect opportunity to test, and put to rest, any doubts about stability. Thanks to an internal lead ballast of 3.5 tons and a displacement of 9 tons, my previous Aventura was as stable as any traditionally designed yacht. I need to point out that both the previous Aventura and her successor have an integral centreboard, which means that when the board is raised, it is fully retracted into the hull.
There are many advantages to a centreboard, besides shallow draft. The main role of the board is to provide lift when sailing close-hauled and reduce leeway when reaching. With the board fully down my previous boat drew 2.4 metres and, when sailed properly, it could point as high, or almost as high, as most cruising boats. What I meant by sailed properly is that when sailing hard on the wind sail trim is critical, also a good speed must be kept up and heeling too much must be avoided or you end up making too much leeway. With a draft of 2.8 metres with the board down, the new Aventura is performing even better than her predecessor.
There is a certain technique in sailing a centreboarder efficiently, not just on the wind but off the wind as well. This is when the centreboard becomes a true asset as it allows you to reduce the wetted surface. Also, the ability to lift the board gradually as the apparent wind goes past 135°, and then continue lifting it up to the point where the board is fully retracted, is a great advantage as the risk of broaching is virtually eliminated.
The absence of a keel to act as a pivot in a potential broaching situation means that the boat does not tend to round up when, in a similar situation, a keeled boat would do just that. It is a feature that I have blessed on many occasions, and that had allowed me to continue keeping the spinnaker up longer than I would have done otherwise.
The board is normally retracted when motoring in calm waters and the reduction in wetted surface provides an extra 0.3 to 0.5 knots of speed.
Why do I consider shallow draft to be so important?
Jimmy Cornell: In all surveys dealing with the subject of ideal draft there was a consensus that whereas a fixed keel may be best suited for ocean passages, having a shallow draft when cruising is not only ideal for exploring places that other boats cannot reach, but also safe because it allows you to tuck into a protected spot if needing shelter in an emergency.
Indeed, one of the main reasons for choosing a centreboarder is to increase my cruising options, and having a boat whose draft can be reduced instantly is a huge advantage. The fact that most integral centreboard boats have a flat bottom means that with the board fully up the boat can dry out on any beach, tidal bay or estuary. When the tide runs out, the boat settles down comfortably, and, as the height of the stern platform is less than one metre above the dried out surface, access aboard is very easy with the aid of the swimming ladder. We have dried out on many occasions, whether to put on a quick coat of antifouling between tides while cruising the Chilean canals, or to access a shallow bay in Alaska so we could watch grizzly bears fishing for salmon.
One other advantage of having a centerboard is that it can be used as a sounding board when entering an unfamiliar shallow anchorage. It is a technique I learned from an old friend and taught me a new meaning for the term ‘sounding board’.
Why don’t you have a wind operated self-steering gear on the new Aventura?
Jimmy Cornell: The main reason is the stern arch that makes it impossible to use a windvane efficiently. Also, this is an exploration boat when steering an accurate course at all times is essential, and in such situations an autopilot does a better job than a windvane.
I wish to also point out that as generating electricity from renewable sources has become such an efficient matter (I have a wind and hydro-generator, and a solar panel), using an autopilot no longer needs to be a drain on energy, which used to be the greatest advantage of a windvane.
How vulnerable are your rudders in a collision?
Jimmy Cornell: The two rudders are of strong aluminium construction, supported both by skegs. An ingenious solution had been found to protect a vulnerable area in case of frontal collision, when the shock can push the rudder blade upwards and possibly damage or even penetrate the hull. The upper section of the rudder blade incorporates a crumple area made of light composite material. Should the rudder be pushed upwards in a collision, this sacrificial area will crumple and compress without causing any damage to the hull itself.
This special feature was put to the test when we collided with the underwater ledge of an iceberg while sailing in the Northwest Passage. The shock was so hard that it knocked me off my feet in the cockpit. It was only about two weeks later that I noticed the damage from the dinghy. The crumple zone had done its job and the damage was purely superficial. Aventura continued sailing like that until we returned to the boatyard in Cherbourg where the rudder blade was extracted and the crumple zone could be rebuilt.
What provisions do you have for emergency steering?
Jimmy Cornell: Aventura is not set up for the standard type of emergency tiller as such, for the simple reason that she has two rudders, each provided with an independent steering mechanism. In an emergency it only takes a few minutes to disengage the connecting bar between the two steering mechanisms. As a result, the rudders can be used independently of each other. This system also allows that either wheel can steer either rudder. Furthermore, Aventura has two entirely autonomous autopilots, either of which can steer the boat with either rudder (as per the above arrangement).
All this shows that the Exploration 45 is not a run of the mill standard production boat, but a specially designed long distance cruising boat conceived – above all – as a safer boat that any other currently on the market. The emergency steering arrangements are an intrinsic part of this safety aspect. Does such a boat really need also an emergency tiller?
In fact, there is provision for an emergency tiller for those who wish to have one. There is a universal bracket on the stern platform that would take an emergency tiller of the type made by Windpilot, the German firm manufacturing the Windpilot wind self-steering system. That universal bracket is also used for the Sail-Gen hydro-generator and also can be used as a bracket for an outboard motor in an emergency.
In your book “A Passion for the Sea” you described the rig of Aventura III as perfect. If that was the case why did you make several changes to the rig of your new boat?
Jimmy Cornell: There are some major differences between the two boats:
Aventura III had a masthead rig, in-line spreaders and a yankee (high cut jib)-staysail configuration. So it was a proper cutter rig and the yankee and staysail worked efficiently together.
One major concession that I made when we discussed with the designer and the builder the rig of the new Aventura was to abandon the cutter rig in favour of a Solent jib/staysail configuration. On my previous boat the yankee-staysail arrangement had worked well.
Sailing hard on the wind is the weakest point of a centreboard boat, and this is where a flat cut jib is an advantage. The current Aventura has a fractional rig (7/8) and back-swept spreaders, with a Solent jib (low cut, relatively flat sail) and a staysail to be used on its own in stronger winds. They are not meant to be used together, as on a cutter, although I have occasionally experimented with using both sails, usually partially rolled up.
Windward performance is certainly a potential weakness of a centreboard boat with a relatively flat bottom, but with the sails well-trimmed and the full board down, we managed to sail as close as 35 degrees to the wind. On a test sail in Cherbourg harbour, in 25 to 28 knots, with a full staysail and two reefs in the mainsail, we once hit 9.5 knots. I must stress that she was not yet fully laden, although the fuel and water tanks were full. This meant that we could try out one of Aventura’s special features by using the two transfer pumps to quickly move close to one tonne of weight into the windward tanks.
How environmentally friendly is your new Aventura?
Jimmy Cornell: One of the most important features that I wanted was to have as low a carbon footprint as possible. To my great disappointment, I was unable to implement the original plan of having a hybrid engine (I drive a Toyota Prius and am delighted with it), for the simple reason that the few that have been developed for marine use were considered unsuitable for the kind of voyage that I had in mind.
None of my previous boats had a diesel generator nor does the new Aventura. I made up for it by covering as much of our energy needs as possible from renewable sources. The combination of a D400 wind generator, Sail-Gen hydro-generator, and a 140 watts solar panel, have fulfilled our energy needs on all offshore passages.
This was demonstrated on the final passage from Greenland to England where we had a problem with our engine and had to rely on the above equipment to provide all our energy needs, which it did perfectly.
Also with the environment in mind, both the grey and black water are treated by an Electroscan purifying system before being discharged.
What are the main safety features of the new Aventura?
Jimmy Cornell: Foremost, the way the boat itself was built. The hull is of a very strong construction and is provided with two watertight bulkheads. Safety and comfort played a major part in designing some of the special features of Aventura, such as the navigation station with 270 degree vision and access to engine controls and steering, or the protected watch-keeper’s position in the forward part of the cockpit.
There are several built-in backup systems, such as the two-rudder configuration. As a concession to my insistence on safety, and the possibility of collision with ice, the proposed composite rudders were replaced with aluminium rudders, protected by skegs.
For similar reasons, I rejected the suggested saildrive in favour of a traditional propeller shaft. Also, I kept the standard fixed propeller for the Northwest Passage and replaced it with a folding propeller at a later stage.
The fuel day tank can also be regarded as a safety feature. I had one on every one of my previous boats and regard it as essential on any long distance sailing boat.
To make it easier to launch the heavy 8-man liferaft, this is stowed in a special compartment from where it can be easily dragged across the stern platform. Next to it, in its own compartment, is a large double reel for the stern anchor rode and stern mooring line.
Many production boats do not have comfortable single berths. Is that the case on the new Aventura?
Jimmy Cornell: Much thought had gone into the interior arrangement where I told the designer that I wanted to have as many comfortable sea berths as he could possibly squeeze into a 45 foot boat. As a result, Aventura has two double cabins, as well as four single berths, two in the starboard aft cabin, two on the portside of the salon.
