Frequently Asked Questions

A monohull is best suited for those who want "to push the latitudes" and notably navigate where ice can be encountered. Multihulls certainly offer an attractive law draft and vast living areas. However they offer less load carrying capacity vs. a beamy monohull. If rolled over by a rogue wave, multihulls, more stable upside down, will not be able to navigate back from remote areas; while on a monohull there is a possibility to establish a jury rig if the mast is broken or gone. Also some standard cruising size catamarans (around 50 feet) tend to behave like a snowplow with ice jamming between the hulls, drastically hindering progression when ice is on the way.

A cutter rig or a sloop with a self-tacking furling staysail is ideal for a short-handed crew. Furthermore the sail plan remains balanced across the wind range. In more details the CE (Center of Effort) remains centered while reefing/furling the sails and keeps an appropriate relative position vs. the CLR (Center of Lateral Resistance).

A schooner, or even better for this size of boat a ketch, would offer a safety advantage given the addition of a 2nd mast. Some sail surfaces would be smaller, however more maneuvers would be required to keep the boat balanced. More importantly on this size of boat, the sail plan would be far less performant, given the relatively short distance between the 2 masts. The boat would tend to be heavier too, with a higher center of gravity, due to the additional mast and more complex rigging.

Aluminium guarantees a stiff, strong and safe ship. Resistance to puncture following sudden impacts with floating debris or containers is crucial for safety at sea. Marine grade alloys resistance to puncture is excellent due to the ductile nature of aluminium.
A metal hull sounds like a reasonable safety choice for an exploration "going anywhere" type of yacht or even for any long passages ocean going vessel. Compared to steel, aluminium is not only lightweight (3 times lighter), marine aluminum alloys offer low maintenance and are extremely durable. An aluminium hull doesn't need to be painted.
However aluminium boats need to be well insulated and ventilated for both hot and cold climates. To keep a comfortable temperature inside and moreover prevent condensation. Electrical wiring and any paint job required (antifouling below water line or anti-skid on deck) have to be performed rigorously to avoid any potential corrosion issue. When done correctly an aluminium hull will last for multiple decades. Re. environmental footprint aluminium is fully recyclable.

A low draft is required for a true "go anywhere" boat, without undermining upwind sailing performance. To possibly anchor in more sheltered areas, or gain protection from drift ice by being able to enter shallow waters where large floes cannot get in.
This leaves the choice between a lifting keel and a centerboard. A swing or pivoting keel with a security device is best suited in case of collision or accidental grounding, the vertical lifting keel arrangement being far too vulnerable. An heavily ballasted keel weighting up to 10 times more than a centerboard requires a more sophisticated lifting device and also yields more inertia in case of a sudden shock with debris or marine life.
Also with this last option it is not possible to navigate with the keel up and at anchor once the keel is lifted, the boat becomes rolly due to the significantly higher position of the center of gravity; not the case with a centerboard. During long cruises more time is usually spent at anchor than navigating.

A real advantage of centerboarders is the ability to navigate safely with the board up; no keel broach effect reducing the risk of capsizing and moreover more pleasant and gentle motions going downwind in heavy seas, well appreciated by any crew ! If this broach effect still sounds theoretical, a suggestion is to go and practice a few jibes on a Laser or equivalent sail-dinghy in a good breeze with both the daggerboard up or down and feel the difference, a likely wet but memorable experience !
The ability to dry up completely with the tide, not only opens up a large choice of additional moorings or small sheltered "fishermen" harbors, but also brings side advantages such as being able to perform maintenance work on the propeller or just clean the hull, without having to dive or haul the boat out of the water. On the flip side the ballast of a centerboarder being positioned higher in the hull bottom vs. a lifting keel, more ballast is required leading to an heavier boat. A hull bustle perfectly integrated into the Enduro 54 design allows the lead ballast to be positioned lower, as well as the engine and some fuel tankage, yielding a particularly low center of gravity for a centerboarder. For upwind performance, a long and thick (Naca profile) centerboard has been designed, extending draft from 4 to 12 feet in the down position.

Twin rudders are undoubtedly the best solution for "fingertip" steering and even more importantly less pilot wear and lower electric consumption. Twin rudders are ideally positioned and provide best control in heavy seas. When the boat is heeling, the downwind rudder, while smaller compared to a full scale single rudder, is more efficient given the optimum incidence angle.

A very significant drawback is the exposure and vulnerability to debris impact, being outside the keel/centerboard or propeller skeg protection. As a matter of fact, under heel the upwind rudder close to the surface with no protection from the hull is the most vulnerable. An inauspicious floating container on the way would blow up the lower part (at minimum) of the rudder not protected by a skeg usually positioned higher up closer to the hull bottom.
Stout aluminium construction with heavy scantlings and the addition of protective skegs (compromising performance and fingertip steering as the protection increases) is a solution, but not totally satisfactory.

In remote areas wharfs are not always clear with immersed rocks potentially damaging rudders, or ice drifting can push the boat towards an unsafe shore with shallow rocks... under these conditions a single rudder boat is vulnerable too, which is even more critical since there is no spare rudder left to steer the boat.

Retractable rudders are an attractive solution, especially if they can still be positioned under the hull for optimum performance and well integrated into the transom, not being exposed to potential collisions with a dodgy wharf or other boats in small busy harbors. Immersed lifting devices (cylinders), as well as rudders folding into two halves resulting in poor hydrodynamics are better avoided.

In the case of heavy aluminium expedition boats that almost never exceed hull speed, why a chine ?

Below are real benefits of this full-length chine, without having to further increase beam :

• Enhanced hull stability : crucial on any centerboarder
• Increased power (righting moment) : also meaning less heeling without piling on lead ballast weight, for instance 20 degrees max. acceptable on a cruiser vs 30 degrees on a racing boat
• Directional control : once the chine is submerged (below a 15° heel angle) the boat tends to bear away a little more. This helps balance the boat back. It's almost like adding an extra rudder. Useful in high latitudes heavy seas.
• Enhanced livability : without significant waterline beam increase and at the right place ! Allowing the lay out of 2 central single berths ideally located for use at sea and during long passages.
• Aluminum construction : Having said that, we could have designed a round bilge hull pretty close to this design, for instance by softening the chine edge and smoothing section lines; however this would have led to high curvatures in this area. Given the boat scantlings and thick aluminium plates used for the garboard not easily bent into shape, it would have been difficult to perform a decent job for the boilerplate metal work while retaining the same volumes yielding the advantages listed above.

Nothing can beat the attractiveness of a vast pilot-house with panoramic view, including a navigation station with true inside steering and a comfortable raised saloon opposite an ergonomic galley. Why should you be living in a cave down below, whereas you are cruising in exotic places with striking beautiful scenery around ? How about keeping a view at the outside world while navigating, cooking, eating or just relaxing ?
Furthermore a simple watertight door you can quickly close, in case of bad weather or unsecured areas, is far more convenient and safer than the usual companionway washboards.

It's true that a dedicated place to store the dinghy ready to go would be ideal. However the design of an aft garage on a boat smaller than approx. 60 feet tend to jeopardize the best locations for sea berths, unless one would prefer to sleep in the tender ! An exploration boat also needs a sizable dinghy larger than a below cockpit garage would allow for a 54' boat.

To clear the deck during long passages or the aft arch where the dinghy can hang during coastal cruising, the vast walk-in forepeak of the Enduro 54 can store a 3m60 RIB (below 9 feet once deflated).

A stout aluminium construction combined with a yacht design with autonomy and comforting redundancy in mind, hence with large fuel and water tankage, numerous batteries, lots of spares, large storages for gear and provisions, will not result in a light vessel !
However a powerful and load tolerant hull design can still lead to good average speed and daily mileage, much more relevant than trying to maximize instantaneous speed. The hull design has been optimized taking into account the large tankage plus the additional integration of the bustle. A seaworthy boat enabling the crew to live safely and comfortably, whatever the outside conditions are, will make faster, safer and more pleasant passages.
Having said this, the VPP (theoretical) are still quite attractive, thanks to the powerful modern hull design and sail plan.

For more information see VPP chart included in performances

This boat design combining a hull with outstanding form stability in addition to a relatively low center of gravity for a centerboarder, given the lower positions of the lead ballast, engine and some fuel tankage in the hull bustle, exhibits a stability index of 52 and an AVS of 120 degrees; in addition to being able to navigate safely downwind with the board up hence reducing the risk of broaching or capsizing. The minimum regulatory stability index result required for the CE category A navigation is 32.

It is noteworthy to mention this stability index (see STIX definition and calculations in ISO-12217-2) is much more comprehensive than a mere static figure like AVS and integrates several dynamic factors such as the total energy to capsize a boat, and is based on the worst stability configurations such as in the minimum operating condition or in the loaded arrival condition (precise definitions in the ISO), which in essence means the board up, empty tanks, and numerous crew members on deck, etc. There is no bonus for the broach keel effect reduction, despite the fact the board has to be taken up in those regulatory calculations.

The board in the down position (e.g. going upwind), combined with more usual loading conditions and crew status in normal cruising conditions would yield even better results indeed. Typically a boat with a full load (full tanks and provisions) is more stable given the fact tanks and provisions stores often below floors are usually positioned low. An optional carbon rig would take the center of gravity significantly lower vs. the aluminium rig and boost those stability figures further up.

For more information see stability curve included in performances

Emphasis has been put on using and adapting reliable, simple or proven system concepts to open endless possibilities of cruising into the most remote areas of the planet. So not many new "innovative" high-tech systems on board !

The innovation stems from the attractive combination of a modern hull design with performant lifting appendages together with a vast pilot-house.

The design also benefits from the implementation of several great ideas including many "little", but important for seaworthiness, details gleaned from many years and miles of sailing experience on various boats and from invaluable inputs from some high-latitudes sailors.
A well-thought combination of proven practical and reliable solutions making for a unique boat, crystallized by our own experience of traveling the world and the high seas on an older 45' centerboarder. Last but not least, a consistent project meeting all the required specifications.

The remoteness of these regions where supplies or rescue operations can be difficult, coupled with frequent poor weather conditions and the lack of reliable charts create real challenges. Furthermore the presence of ice, with potential significant loads on the hull, appendages and propulsion of the boat, is an additional hindrance.

In a nutshell, sailboats and yachts specifically designed for cruising in the high latitudes have metal hulls with lifting appendages most of the time and are very solidly built with ice scantling consistent with classification societies rules, possess large fuel tanks and internal steering positions, in addition to sheltered and possibly heated watch areas. As for most recent premium sailboats and performance sailing yachts, aluminum is preferred to steel, being lighter and requiring less maintenance.

» Read more about high latitudes sailing.

A pivoting centerboard and low draft open up many possibilities for safe moorings in shallow water or in small drying harbors, but unless the boat is tied to a fixed mooring in a tidal bay, beaching voluntarily doesn't happen frequently during long distance cruises.

However in case of a problem with the propeller, or just to replace anodes, put an ice protection cage on, or inspect the hull, the possibility to dry the boat out at low tide is a real safety asset for a go-anywhere yacht. Not that many harbors in remote cruising regions where an over twenty tons boat can be safely hauled out. It is even possible to clean the hull, or moreover scrub and anti-foul between tides. Can be useful on boats with fixed or folding rudders after a collision too.
On the Enduro 54 the retractable rudders can be removed while in the water, in a quiet anchorage or harbor, with still water indeed. As a matter of fact (and experience), just changing anodes is not so easy when diving, with the boat moving at the time you are trying to set small screws or nuts in, driving you nut..., even in warm waters where wearing gloves isn't needed. In cold water, numb fingers won't help !

A boat which can take the ground easily, dry out on any beach or tidal bay, is definitely safer and best suited for exploration or just cruising off the beaten track.