For extensive cruising, but like most of the nautical press seems to consider, not really a bluewater boat for long ocean voyages. Sure, in any boat you can make extensive ocean voyages, even in the most unsuited for them, but not taking the same risks or with the same comfort.
The comparatively higher STIX number (due to size, displacement, and small sails) would indicate a seaworthy boat for the size, but the RM at 90º will be small (for the displacement), and if knocked down this boat will take a considerable time to rise, especially if there is water in the sails, and will be exposed, with little remaining stability, to the next wave, that can invert it. Once inverted this very beamy boat with a relatively small AVS will need many minutes before a right-sized wave can upright it.
As a class A sailboat, you have to consider it as one that passes the mandatory requirements by a narrow margin and I had already made an article saying, and explaining, why the assumption that a Class A boat is a bluewater boat is misleading. There are Class A boats that pass the certification by a very narrow margin and others by a huge margin and the seaworthiness can be very different even if both are Class A.
https://interestingsailboats.blogspot.com/2019/05/please-rcd-certification-for-bluewater.html
But this does not mean that the OVNI 370 is not a very interesting coastal cruiser with offshore ability, a very strong boat with options that can make it very suited for extensive cruising and anyway most sailboats cruise in the med, Baltic, Caribbean or Bahamas, without never crossing Oceans, and many sailors never sail with more than F7 or F8 while doing coastal cruising, and that is possible due to the relative precision of weather forecasts.
The bigger beam gives cats bigger stability, even if the ballast on the bottom of a centerboard contributes to leveling the field. Anyway, a 36ft cat, if it can manage a Class A certification, does that also narrowly, and it has to be a relatively heavy one.
The interior is nice and very bright allowing for a true deck saloon with a view, a rare thing these days. The very big beam (3.99m) the large freeboard and the considerable height of the cabin make possible a huge interior that is maximized by the bow and stern shape. To see how good the interior is go here and click on Virtual Visit, one of the best I have seen: https://www.alubat.com/la-gamme/ovni-370/
So, a lot of compromises regarding sailing, but as positive points, I may add that today all boats designed by reputable cabinets are well designed and even if miracles should not be expected the sail performance is not bad and the very deep centerboard (3.08 meters) contributes for minimizing the less good upwind performance.
Even if it is not a boat I would be interested in having for cruising (due to the less good sailing performance), this is a very interesting sailboat that will serve perfectly the needs of many cruisers, offering fewer worries in what regards damage in pontoons with bad weather, or regarding hitting submerged debris, offering an incredible amount of nice space, great views to the outside, surprising tankage (300L water, 300L diesel) and an integrated arch for solar panels or for suspending a small dinghy.
On their site, they gave the OVNI 360 the same dimension for LOA and HL (11.95m), and that is impossible because the 370 has a fixed integrated bowsprit, so obviously one of them is wrong. The OVNI 400 has a very similar bowsprit, and we can know the length of that bowsprit by the difference between LOA and HL (62cm).
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| The OVNI 370 and the 400 |
Maybe the reason has to do with the 40fter being a very different sailboat, having a much better overall stability, while this 39fter, with considerably less stability, but cheaper to build, with a not very different interior space, offers a more attractive solution for coastal cruising, due to the difference in price.
That seems fine to me, but not fine the fact that they did not make all this clear. Let's look at the two boats' stabilities and I will show you why even if the boats have not a very different length the 400 has much more stability than the 39fter (370) and it is therefore much more suited for bluewater cruising.
The difference in displacement between the OVNI 370 and the OVNI 400 is 1800kg and because stability (RM) is obtained by multiplying mass versus GZ (righting arm) we can understand that only that difference in displacement corresponds to 19% more overall stability, for only a 3% increase in length, but in reality, that difference is much bigger because the 400 righting arm is bigger than the one of the 370.
The small difference in size corresponds to a big difference in what regards seaworthiness and overall stability, probably the one that corresponds to the difference between a 37ft boat and a 40ft boat and if we take that into consideration, calling 370 to a 39ft boat makes some kind of sense.
https://interestingsailboats.blogspot.com/2018/11/ovni-400-modern-aluminium-voyage-boat.html
https://interestingsailboats.blogspot.com/2019/11/new-40ft-voyage-aluminium-boats-ovni.html
Regarding price, aluminum boats are more expensive than mass-produced bonded sailboats and 272 000 € (at the factory, without VAT) does not seem excessive, and the fact that this boat does not need, like the 400, a hydraulic system to raise the keel contributes to that.
A nice quality strong yacht at a fair price, for the ones that want a coastal cruising boat with great features in what regards cruising amenities and with extra security in what regards the possibility of damage due to floating debris and possibility of damage in pontoons or quays, under heavy whether.
For the ones that want to buy an aluminum boat, it may be useful to know that they should make it as soon as possible because prices have raised in an incredible way (+83%) and when they finish their stock that will impact strongly on boat prices.
Hello Paulo, thank you for your insightful analysis. IMO the issue of stability of bluewater yachts should be given much more attention.
ReplyDeleteI just compared the technical information of the three OVNIs (370, 400, 450). To my surprise, the one with the lowest B/D ratio is the 450 - 32% vs. 35% for 370 and 400. The 400 carries 33% of its total ballast in the foil, whereas in the case of the 370 it's 8% and in the case of the 450 it's 13%. Unless I miss something, I'd wager that the 370 and 450 might offer similar stability, and only the 400 might have a relevant advantage in this respect.
Best,
Markus
Not in what regards overall stability: due to a bigger displacement the one of the OVNI 450 will be bigger.
DeleteRegarding the CG you have also to consider than in a bigger boat it is possible to have bigger and more flat tanks and that also counts to lower the CG, especially considering that the 450 carries 500L diesel and 540L of water.
But yes, the AVS and the safety stability should be not very different, but with a difference in seaworthiness, that is taken into consideration in the RCD: a heavier boat will be harder to capsize and therefore the AVS needed to certify the 370 in Class A is bigger than the one needed to certify the 450.
Thank you for your comments, Paulo. Makes perfect sense!
ReplyDeleteBTW, I reviewed the ballast ratio of older OVNIs, to have a reference. The 395 had 32%, i.e. less than the current models, but the 385 what a whopping 55%. Different times ... ;-)
I make the 395 ballast ratio 36%, the 385 as a new model showed 43.8% on the initial 1999 brochure, the 2003 brochure reflects the true displacement and changes the ratio to 34%.
DeleteBut no-one is talking about form stability either which is increased by the chine construction.
And, perhaps more importantly, none of these calculations factor in the skipper and crews ability. Aren't Volvo's supposed to be the safest cars? Still possible to flip them and do yourself some damage if you don't drive it well. Same with yachts. Sailors need to know how to sail according to the conditions and their crew capability rather than relying on theoretical calculations.
Form stability is bigger (more beam, beam pulled after) and the new OVNIs sail better, specially downwind and beam reaching, but form stability does not increase stability at big heel angles or increase the AVS. For that what really matters is the lowering of the CG, that is obtained with ballast.
DeleteSure. Any boat can be capsized including VOR, even if it has never happened, and they are pushed to the limit is some of the worst seas of the planet.
What is important is to know the seaworthiness and characteristics of the boat you sail, but also to know its limits, stability and even AVS. Fact is that many judge too optimistically the stability characteristics of a boat like the OVNI 370, especially in what concerns safety stability and AVS.
As I said, it is a class A boat, but one that passes the minimum criteria not by much, and it is important that the ones that sail that boat know that, for acting accordingly.
Thank you for sharing Paulo. Very good content.
ReplyDeleteHello Paulo,
ReplyDeleteThank you for your article but studies of the stability and performances of a boat are not only a question of ratios between displacement, size and weight of the ballast. This is more complex and this is the reason why naval architects are very important in the conception of boats.
We would like to invite you to come at the shipyard to see our OVNIs so you will be able to appreciate that there is a difference of 95cm long between the OVNI 370 and the OVNI 400. And we propose you to sail test the OVNI 370.
For your information, the OVNI 370 is category A certified and the AVS is well above the minimum required by the regulations.
Hi!
DeleteBecause many brands don't post the stability curves an educated guess about the boat CG taking into consideration B/D and position of ballast CG, shape of the hull and cabin, is the only way to provide some more or less reliable. information.
But of course, if you provide me with the the 370 stability curve, in min sailing charge and max charge, I will be happy to post it in the article and increase the reliability of the information.
I know that the OVNI 370 is certified Class A, but the Class A requirement is so low that there are some light 23/27ft boats that pass it too.
Paulo, you provide valuable analysis of stability factors, but I find the obsession with "capsizing" somewhat singleminded. Capsizing without other contributing causes does not even closely represent the majority of fatal shipwrecks in the ocean. I'll try not to offend any modern manufacturers, but merely refer to the common failures of boats from the 70s-80s: rudders falling off, keel coming loose, rigs collapsing - and of course the major risk today: hitting floating debris. I have owned an Ovni 395 for 15 years, and frankly I'd choose the 370 any day merely because of its aluminium construction - and of course the keel: I once hit a sizeable log in the ocean and heard three bangs: first at the bow, then the keel, then the rudder. The keel swung out of the way, the rudder released its safety mechanism and swung away, and back in port I could confirm zero damage to any part of the boat. Had this been a regular "Class A" boat, the keel might well have broken with not only a "capsize" as the result, but with a doomed ship even if it didn't.
ReplyDeleteThe 370 has even thicker aluminium than my 395 (a cost-saving measure the allowed them to drip longitudinal stringers, but comforting nevertheless).
A Class A boat is a total package, not merely a hull and displacement. I still find it incredible that in 15 years of sailing - often rough, in northern waters - not a single rig detail has failed on my 395. Not one fitting has come loose, no leak has occurred either from sea water or rain. A lot has to do with the fact that hull and deck is a single welded piece, deck fittings are welded not screwed through.
To describe the Ovni 370 as a "coastal cruiser" is simply off the mark. Take a look at Vendee Globe around the world races and tally up the number of shipwrecks, some fatal, due to hitting flotsam, and you get some idea of the real-world risks out there. Add the thought that you could lose the keel (however that should be possible with asking keel) and still have the ballast and buoyancy, you could even continue sailing. Finally, remember that you can "surf" off the storm by lifting the keel and avoiding the summersault we fear most in a fixed keel boat (a friend of mine in a 365 forgot to do it and did capsize, to his great embarrassment). Put together, so may safety factors weighed against your single calculated weakness, hull stability. BTW, the shipyard can apparently not after 60 (?) years of operation recall an Ovni being lost due to capsizing.
Some of the things you say make sense BUT some years ago I talked with a German (or Swiss?) sailor (in Dusseldorf) that after circumnavigating 2 (ot 3?) times in an OVNI was looking for a strong fiberglass boat. His OVNI had hit a stone and (in his own words) it opened like a can of sardines.
DeleteThe stability, relation between positive and negative stability, and the AVS are not the only factors in what regards seaworthiness, but they remain an important factor.
Take into consideration that when a boat capsizes many times it does nor reach the news. Here you have a video of an aluminium boat, more expensive and better built then the OVNI, going down after being capsized by a wave.
After too much time it righted itself, but full of water and with the initial stability compromised, it went under. It can happen to yachts with a poor AVS.
https://www.youtube.com/watch?v=vF0UPm1rs5Q
I can see we’ll not entirely agree, and I would never discount your assessments on AVS. I can only repeat that as a percentage of catastrophic incidents AVS alone comes a long way down the list of factors.
ReplyDeleteA case in point was this year’s Sydney to Hobart race, along with all of those races going back years: seas were rough but far from the worst on record, and retirements followed the familiar pattern: rig failure, rudder failure, hitting debris – and rig failure, rig failure, rig failure. Yes, boats get knocked down, but in so many cases it began with something else: rig or rudder placing it at the mercy of the elements, not maneuverable. If there is one thing Ovni owners will testify it is that their rig made the grade, and that anxiety about the keel or rudder is so much reduced that it helps them sleep.
To be facetious: you mention the Ovni that hit a stone. That would be the least of my worries; stones do not tend to drift about in the ocean, hitting you without warning. Logs and containers do. I have sailed through ice a number of times, to the point where the engine could not break us through. No hull damage. But I particularly recall one time with rather thin but all the sharper ice that cut a perfect line through the antifouling paint. A colleague made the point that a wooden hull would have been sliced open as if by a saw blade, and he was unsure how a fiberglass hull would fare. Ours became a minor paint job.
There are different ways to achieve true blue water sailing, and centerboards with ballast in the hull isn’t such an unwise choice. The very fact that staying upright does not depend heavily on the keel remaining attached is also AVS in action. Any boat can be knocked down, and if rig and other gear is damaged in the process it does not have much remaining protection from the elements. Short of copying life boats with a tough watertight passenger compartment, every design has circumstances in which it will fail. Personally I would not entertain a false sense of security just because the AVS is convincing.
It seems to me you misinterpreted what I said. I don't consider aluminium center-boarders an unsafe or not adequate solution for bluewater sailing, quite the contrary, and I agree with much of what you said.
DeleteBut I am not raising doubts about the suitability of aluminium centerboarders as sailboats especially adequate for bluewater sailing, but the suitability of aluminium centerboards with less then 40ft, and the reasons seem clear to me.
A 37 ft boat with 9400kg displacement with 3000kg ballast inside the boat is not a boat with a big overall stability, considering that when capsized it will be difficult to re-right itself (there is a video with a bigger aluminium centerboarder going down after being capsized).
That does not mean that will happen frequently, only that a centerboarder with a bit over 30%B/D has to be bigger enough, and heavy enough, for making the possibility of a capsize an almost impossible event, much more than a monohull, with the ability to re-right itself easily.
The Dutch built for many years centerboarders, some of this size, also with all ballast inside, but their designers did not put 31% of the boat displacement in ballast, but around 50%, given it an AVS that would allow it to re-right easily if capsized. Sure, that made them slow boats, but, size for size, more seaworthy, while sailing oceans.
My position regarding this is similar to the one I have about catamarans, that as you probably know, have displacement for displacement, a much bigger overall stability than a monohull, but they are not able to re-right themselves, and therefore, to be safe crossing oceans they should have a given size and weight that makes them very difficult to capsize, being that size and weight much bigger than the minimum one that is considered safe for a monohull, I will say 38/40ft, if they are condo cats or 44/45ft if they are performance cruisers, and it is not by accident that these are the sizes catamaran builders of each type of cats start their lines.
In the Pacific Northwest, it is all about the logs.
ReplyDeleteHi Paulo, I found your article and comparisons of the 370 and 400 insightfull although I do think that the skipper/crew ability to sail well outweighs all the stability formulas put together. Today the 400 is no longer in production and a 430 is proposed as, I guess, the real deal in terms of 'blue water boat'. I look forward to your comments on that model also.
ReplyDeleteWhen you are hit sideways by a bigger breaking wave while beam reaching at night the crew is pretty much irrelevant.
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