Thursday, November 29, 2018

OVNI 400: A MODERN ALUMINIUM VOYAGE BOAT


When I saw on the nautical press the technical characteristics of the new OVNI 40, I could not believe them. They said that the boat has 2600kg ballast and displaced 11200kg. That gives a B/D of 23% and that, considering that the ballast is inside the boat, would not allow the boat to be certified as class A due to a poor final stability and AVS. 

I checked on Alubat site and they apparently confirmed those dimensions. Only when I made the download of the boat brochure did things become different: contrary to what used to be, the centerboard is heavy and acts as ballast. It weights 1300kg, going down till 2.88m (draft). 

Even if the centerboard does not seems to have more weight down than up, that changes things and the ballast is actually 3900kg, with some of it way down. That gives a B/D of 35% that, without being much, considering that most of it is inside the boat, will allow the boat to be certified class A, but I bet, very close to the minimum required in what regards stability. 

The OVNI 395, the boat that this one substitutes, is surprisingly lighter (10 000kg) and with 3300kg of ballast plus the weight of the light centerboard that, if I remember right was something like 300kg, has a B/D of 36%. Considering that on the new boat the ballast CG is slightly lower due to a considerably part being down on the centerboard, the final stability and AVS of both boats should be very similar.

The OVNI 400 in what regards that mixed ballast system has resemblances with the Southerly, particularly the 42, that displaced 11250kg, with 3670kg of ballast having 2100kg on the bottom of the hull and 1570kg on a swing keel that had a max draft of 2.72m. The bigger ballast on the keel allowed the Southerly 42 RST to have a smaller B/D (33%) than the OVNI. 

What this type of boats loses in static stability gains in dynamic stability, regarding a more conventional type of yacht with a big draft and a bulbed or torpedo keel with a similar B/D (or even smaller). This type of boat is able to dissipate better the energy of a breaking wave by sliding over the water instead of transforming it on a rolling movement.

The smaller the area of keel (or centerboard), the better the ability to not trip over the keel and to slide with the push of a wave and these boats can put the centerboard up in really bad weather while running with the sea, escaping from a storm. It is worth noting that contrary to the 395 the 400 loses static stability with the board up. 
The overall stability is considerably bigger on the 400 due not only to a superior weight (more 1200kg) but also due to a hull with a lot more hull form stability. The 400 has more beam (4.35 to 4.11m) but has also all the beam pulled back to the transom. 

This, the weighted centerboard, the much bigger draft of the centerboard (2.88 to 2.10m) makes it a very different sailboat than the one it is substituting (395). The 400 will be slower on light winds but faster on a beam reach and downwind with medium to strong winds. 
Above, OVNI 395, below, Allures 399
But more important than that the 400 will be a much more comfortable sailboat downwind, rolling a lot less and easier on an autopilot, it will sail on a beam reach on a close reach faster and with less heel (with medium to strong winds) losing for the OVNI 395 only in light winds and close hauled and if I believe that it will be so, the bigger keel draft may have an attenuating factor regarding pointing ability, notwithstanding the considerable bigger wave drag due to the type of hull and superior beam. 

The OVNI 400 is a medium displacement boat with a 203 D/L and with a moderate sail plan, one that certainly is accordingly to the boat stability and that on the standard version has a 17.3 SA/D ans with the “performance rig” (with a square top on the main) has 18.9 SA/D. 

It would be interesting to make a comparison with the main competition, the Allures 399 that has also an aluminum hull but, contrary to the OVNI, for lowering the boat CG has a GRP sandwich deck. The Allures displaces 10 900kg, has a light centerboard that weights 200 kg, that adds to the 4000kg of ballast on the bottom of the hull. This gives a 39% B/D that compares favorably with the one of the OVNIs especially if we consider the lighter deck. 

The Allures has a better AVS and a better final stability. Its hull in what regards shape is a bit between the one of the OVNI 395 and the one of the OVNI 400. It has a similar SA/D (215.8) and a SA/D (16.9) not far from the one of the standard OVNI 400 (17.3). 

The sailboat performances should be quite similar, except on strong winds downwind were the 400 should be faster. Both have equally powered engines (50hp), good enough to give them almost a motor-sailor ability and have a large tankage: the Allures 330L water, 400 L diesel and the OVNI, water 550L, diesel 500L. 

What really is much better on the OVNI 400, compared with the OVNI 395, is the interior space, not only because the boat has more interior space due to more beam and the beam all pulled aft, but because the interior is much nicer, with an all around panoramic view that besides that allows to sail the boat from the interior. 
The 3D drawings show a very nice, functional and comfortable interior. The boat has many possible layouts even if on a boat that is aimed at long range cruising the ones with the 3 cabins don’t make sense, if that is the way the boat is going to be used. Both the two layouts with 2 cabins are well thought being the only difference two heads (and a smaller forward cabin) or one head with a separate shower cabin. 

Another interesting feature is a hard sprayhood. But if they use one they need to provide openings for ventilation that are not shown on the drawings. The running rigging has some unusual features, namely a large traveler for the main over an arch and shows also a nice but small traveler over the cabin for the frontal sail on a position that should provide an excellent sail trimming while close hauled.

Not big enough for a big genoa, a type of sail that seems to be interesting on this boat. Probably the position of the stays would prevent its use anyway with the traveler on that position. A new traveler over the deck would be needed for a 140% genoa. 

Four winches are shown on an intriguing position, under the sprayhood. Maybe they are thinking into putting them on a position that will allow their use on a completely protected area but I don’t think that is justifiable. I hope that they revise that because it makes not much sense having all the winches away from the wheels and having to cross the cockpit area to work on them.

I like the boat design with its slightly inverted voluminous bow, raised cabin and the elegant transom arch to support solar panels, wind generator and eventually to serve as davits for a dinghy. The design is from Mortain & Mavrikios a firm that was responsible for some interesting designs but that on the last years has not done much work. 

The OVNI 400 price is not known yet, the OVNI 395 costs around 240 000 euro and the Allures 399 costs around 280 000, both boats standard and without VAT. I would be surprised if they were able to maintain the 395 price, probably it will be close to the Allures price.

All in all a very interesting proposition that could be a lot more interesting if instead of having 1300 kg on the centerboard it had a swing keel with all the ballast on the keel. That could lead not only to a boat almost 1000kg lighter with a better safety stability and a better AVS but also to a more powerful and fast boat, one that could be a benchmark on this category.



4 comments:

  1. Interesting analysis. However, I disagree with your suggestion that it would be more interesting if all the ballast had been put in the centreboard. Yes, it would make the boat better upwind, but that point of sail is not what these boats are designed for. If the ballast required to meet stability requirements was carried entirely in the centreboard, the boat would have low AVS and stability with the centreboard raised, which would reduce the advantage of being able to run downwind with the centreboard raised. Also, a very heavy centreboard requires very substantial mechanical support and lifting mechanism, and raises issues with centre of gravity changes between raised and lowered.

    A mixed ballast system (like Southerlies and this boat) has advantage of being comfortable in a heavy sea, the centreboard can be made longer (because it will not change the boats C of G too much), have less chord (too increase efficiency upwind) and can be thinner. Also less mechanical support. And in the highly unlikely case the centreboard falls out (it does happen - ask RM Yachts!) the hull still has usable internal ballast.

    I've always wanted an "Aluminium Southerly" and this is even better. The only aspect I am less convinced about is the twin rudder arrangement. Nice on a sporty Mediterranean marina-hopper, but a possible liability in kelp and ice. I rather liked the rudder arrangement on the 395 - deep single well-protected fold-up rudder which could take a knocking, and be useful when manoeuvring the boat under power.

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    1. Centerboard falling out? You mean one of the relatively new Swing keels? That is not a centerboard. Can you give more information about what you are talking about?

      Regarding performance downwind the gain of performance that you can have by raising the centerboard is more than compensated by the huge difference in weight.

      On the Allures 45.9 that diference is of 2000 kg, 19% of the boat displacement, both versions having the same sail area and probably the lighter one having a better AVS and final stability.

      You have a point regarding simplicity and maintenance but that does not apply to the Southerly that has also a hydraulic lifting keel that even if it raises less weight it will have the same maintenance as a bigger one.

      I believe these systems can in an emergency be hand operated even if in a very slow way and with a lot of work. There are already many in use and big mass production shipyards have started to use them (Beneteau, Jeanneau).

      I don't think that the reliability of the system in what regards losing the keel or not be able to put it down is lower than any other keel system.

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  2. As I am sure you know the Allures 45.9 comes in two versions - one a classic centreboarder with a light (200kg) centreboard that retracts entirely into the hull and all the ballast internally. The other is a deep-draft lifting keel boat with heavy keel which does not retract but just folds parallel to the hull. The former is intended as a long-distance all-sea cruising boat - when running downwind the centreboard can be retracted entirely and the hull is very directionally stable in following seas. It can also beach easily. The latter is still a good cruising boat, obviously faster in light airs but not as comfortable in very heavy conditions, particularly in following seas where the protruding keel can be a liability if the boat is pushed sideways. I really like the Mortain Mavrikos Ovni 400 design for being a compromise between the two. Having sailed a few of the modern Southerlies they really have a nice comfortable motion which I am more interested in than outright speed in a cruising boat.

    I have not yet seen an Allures 45.9 with lift keel in the water, but it would be interesting to see how much the CofG is pushed backwards with the keel up. I have seen a few RM lifting keel boats in the water and it is very noticeable how bow-up they float if the keel lifted.

    Back to the RM, the story I heard is that one of the new lifting keel boats had just completed a transat and was at anchor in the Caribbean when the keel fell out. Apparently the factory were very reactive and so the story has not had much press coverage. Maybe just fake news, but the person who told me is serious and well connected in the French yachting scene.

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    1. Both versions have a very similar seaworthiness. Yes, the centerboard is more easily beached but that is a thing one does very rarely. Both have the ability to look for shelter in very shallow waters.

      Regarding boat motion and comfort I don't believe you will have any significant difference. the hull is the same, the RM also and the stability curves are probably very similar.

      Regarding being faster in light airs the 2000kg difference is so big that we will not being talking about being faster or slower but about being stuck in the water or sailing. The 2000kgs heavier version carrying the same sail (same RM) will be sailing many times where the heavier version will be motoring. This can be important to some or not, it depends how much one likes sailing versus motoring.

      Also the differences in speed will not be only in light airs but in practically all wind/sea conditions conditions and very much so upwind. We are talking about a boat with the same sail area but less 2000kg, this means a much more powerful boat.

      Some are not used to the idea that RM/weight is as valid as a potential sail power measure as it is the number of HP a engine have. Simply the version with the swing keel, with all the ballast on the keel, is a much more powerful sailboat and that will not be patent on light winds but on all wind conditions.

      The boat will have more power to sail against any sea, like if it had a considerably more powerful engine and this is very important when the conditions are hard and the seas big.

      Also downwind with strong wind the lighter version will be able to reach a semi- planning condition and will go easily some miles over hull speed while the 2000kg heavier boat will be buried in the water: 2000kg is a lot.

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