Let´s be practical. Are we in the right way?

Discussion in 'Stability' started by Antonio Alcalá, Nov 6, 2007.

  1. Antonio Alcalá
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    Antonio Alcalá Ocean Yachtmaster

    Most of the designs saling around the world are not classic designs. In fact most of the boats for chartering or another commercial use are not Hallberg-Rassy, Contest,Malö, Colin Archer, Hans Christian,Nauticat, Irwin, Vancouver.
    They are Beneteau,Jeanneau, Bavaria. Every year in coincidence with differents events, we start to know about new designs. Everybody knows what I mean, but anybody dive in deep about their qualities and faliures. And, don´t forget, these designs are the 90% of the total fleet. Let´s focus on them. Maybe is not a really pure discussion in this forum, they are not offshore boats ( but all of them are CAT A), but all of them have been in dificulties in coastal waters with rough sea....or maybe this is the post we need from now on.

    Antonio

    www.aecyr.es
     
  2. Vega
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    Vega Senior Member

    Olá António. I am not sure I understand what you mean. Have you been in difficulties with your 43ft Beneteau on coastal waters?

    Do you really believe that a 50ft Benetau or Jeanneau (for example), or even your boat, if correctly equipped is not an offshore boat? Or that they are less seaworthy than some of those boats posted by Guillermo and published on PBO magazine as examples of offshore boats?

    I mean for example:

    Vancouver 28
    - Nicholson 32
    - Victoria 34
    - Vancouver 34
    - Malö 34
    - Moody 346
    - Starlight 35
    - Warrior 35
    - Nicholson 35
    - Rival 36
     
  3. Antonio Alcalá
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    Antonio Alcalá Ocean Yachtmaster

    Hi Vega:

    Of course I think my boat is made for offshore passages.Her STIX goes up to 51, calculated by Guillermo. In fact I´d really sail faster than in another traditional design , that means less time but less motion comfort too, more acceleration with waves and therefore more seaworthiness. But I ask you Vega, why everybody analyses strong and classical boats when the high percent of sport fleet not belong to the select group of Santisima Trinidad ( Hallberg-Rassy, Malö and Contest). I mean...Why most of the naval engineers in this forum don´t they worry more about designs than usually we see habitually in our ports because those are those that the most of the navigators they have. I greatly believe that the interest by this forum would grow up if the different models from Beneteau were analyzed, Jeanneau, Bavaria, Hunter, Elan, etc step by step, boat by boat and year by year


    Best Winds
     
  4. Guillermo
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    Guillermo Ingeniero Naval

    Hi, Antonio!
    As I told you when we talked about this, the 51 figure for Beneteau 473 GTE's STIX may not be such. Something sounds not quite right.

    Regarding the quick accelerations and less motion comfort, It was expectable because of the low MCR and D/L ratios (mitigated by a nice Lwl/Bwl one). (By the way, I think you mean less seaworthiness, not more...:confused: )

    As I told you, I don't think increasing ballast will be such a good idea. That will bring into consideration a lot of other things to check and possibly change. I rather like more your other idea of going for a Hallberg Rassy or the like. :)

    By the way, congratulations because of your solo Cádiz-Canary-Madeira-Cádiz trip!

    Cheers.
     
  5. Vega
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    Vega Senior Member

    Hola Capitán:p

    Well, the one who likes to analyze boats in the forum is Guillermo and in what regards cruising boats I believe he only likes strong and classical boats (he owns a strong and heavy motorsailor).

    Unfortunately he does not only like heavy boats but he seems to consider that light production modern boats (he calls them beamy boats) are badly built, not fit to go offshore and have a very limited seaworthiness. So, he tends to analyze all cruising production light boats very negatively, even those that are a reference among fast cruisers, like the RM1200.

    Recently he analyzed the Jeanneau 36i very negatively. It seems to me one of the best among its peers and I remember, that some time ago, he said disagreeable things about the Etap 28, also considered generally by the press as one of the best boats in its segment.
    I am sure that he does not do that on purpose, simply the parameters he uses to judge boats are not the same as the boat market (and buyers follow).

    I would like very much to see Guillermo with a more open attitude when making boat analyses. If he could abstract from his own point of view, that is based on his very particular tastes, and could judge boats according to the type of sailors they are made to (sailors with different tastes and needs), we would have a richer forum and a different and more varied stability boat analysis.

    But you should not forget that you cannot real analyze a boat without analyzing the construction and most of all, without test sailing it. I have seen stability curves that seem to give a fantastic sailing boat and its sailing qualities are only average; and very good sailing boats, prized by their seaworthiness, with apparently not so good stability curves.

    I believe that other Naval Architects have no time or will to post boat analyses, but I second your opinion about the interest. Most people would like to know more about the boats they are going to buy, and those are not Contests or Malos, but Beneteaus, Jeanneaus and Bavarias;) .
     
  6. Antonio Alcalá
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    Antonio Alcalá Ocean Yachtmaster

    Hi Guillermo! Thanks for your words. But now let´s forget my Beneteau 473, a great boat on the other hand, unless for me. Let´s talk about designs of Beneteau and Jeanneau in the 80´,90´ and nowadays. Let´s compare them with the newest models....What are looking the designers for? Speed with stability or speed with problems...less motion commfort but more terrific sensations..

    This is the discussion applied boat by boat, those we see every day in ports

    Best winds
     
  7. Antonio Alcalá
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    Antonio Alcalá Ocean Yachtmaster

    Hi Vega:

    When you say " believe that other Naval Architects have no time or will to post boat analyses, but I second your opinion about the interest. Most people would like to know more about the boats they are going to buy, and those are not Contests or Malos, but Beneteaus, Jeanneaus and Bavarias" you have to know I´m totally agree with you. This is the feeling of my post.

    Guillermo is a great professional, but he efectively should consider another posibilities when somebody is going to buy a boat. Not everybody have 600.000 Euros for a HR,Malö,Contest,Najad,Swan,Jongert, etc..most of the people only can spend time and money in Beneteau,Jeanneau and etc. These are sailors too and probably better than those who have a HR. Let´s talk about it!!!!

    Best
     
  8. Guillermo
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    Guillermo Ingeniero Naval

    OK, Antonio. If you provide me with data on whatever specific boat, I'll do the analyzing and let you know my opinion (Only one at a time, please!)

    Note: I'm leaving for the Barcelona Boat Show tomorrow in the early morning, so I will not take care of Boatdesign.net matters till next week. Till then.

    Cheers.
     
  9. Vega
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    Vega Senior Member

    That's not only that. Not all sailors with the money would choose a Najad an Halnerg-Rassy or a Contest. Some would find those boats boring and slow. I believe that some would prefer to those boats a First 50, no matter the price difference. Others would say that all plastic boats are unsafe and would only want an even slower and more expensive steel custom boat. Nor right or wrong here, but there is a boat for any kind of sailor, even for those who hardly sail:D . Money isn’t everything;) .
     
  10. MikeJohns
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    MikeJohns Senior Member

    Paulo

    The vessel speed has little to do with the material if you are talking 50 footers unless you get into exotic expensive materials.
    Remember a considerable proportion of the material (by mass) in either a plastic or steel monohull is actually lead :)


    What tends to happen is the designer of a larger heavier vessel will use steel because it's more suitable (cheaper and lighter than solid GRP ). On the other hand a lightwieght performance vessel is less demanding of its design scantlings and would be cheaper to mould in fibre reinforced resins.

    More important to the performance of a "heavy" vessel is what we used to call the power of the hull, just how well does she stand up to her sail to windward. Some of the ratios like SAD are misleading if not read in conjunction. with heeling vs righting moments.

    Jimmy Cornells cruising surveys (ARC organiser) are interesting.

    I notice a significant difference between cruising lifestyles and vessel suitablity depending on the geographical area of operation. Metal boats are a high proportion of Pacific cruisers I think close to 50% now according to Cornell. Modern lightweight composites lack the reserve strength that is so beneficial and inherant in metal boats. Also heavier boats are more suited to the long passages and required fuel and stores.

    My own experience is that in the Trade wind belts you can get anything to move at hull speed with minimal sail but you often slow the boat down to gain comfort.
     
  11. Antonio Alcalá
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    Antonio Alcalá Ocean Yachtmaster

    Could we start for example with 3o feet? Beneteau, Jeanneau and anothers. Depending on their design wich of them is in your opinion more safety according the stability criteria. In wich of them you´d try an atlantic cross to west ( not to europe). Are there any of these with severe problems of stability and can they solve with ab adequate experience of the skipper?

    Best winds
     
  12. Vega
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    Vega Senior Member

    Mike,

    Among the few builders that have sufficient orders to maintain a production of semi-custom steel cruising boats is “Motiva”.

    They make very good boats for the kind of sailors that like that kind of boat, and the longevity of the shipyard attests that fact.

    http://www.motivayacht.dk/

    They have a 49ft boat (picture). The boat displaces 25 000kg for a ballast of 7000kgs and a sail area of 120m2.


    Among the many builders that manufacture modern light production boats I will pick Beneteau that has two new cruisers:

    The Oceanis displaces around 13 000 kg, has probably a ballast of around 4 000 kg and has 112,4 m2 of sail (picture).

    And for more speedy cruisers,l Beneteau has the First 50. They call it a cruiser-racer, but it's really more a fast cruiser than a racer, and the interior shows that (picture).

    The boat is a little bit heavier than the Oceanis, but with a ballast of 4300kg in a low bulbed keel, it has the RM needed to carry 138.7 m2 sail.

    These are not expensive boats for their size and they are boats with a clear offshore capability and don’t incorporate what you call “exotic expensive materials”.

    You are saying:

    Do you really think that a 50ft boat with 25 T and 120m2 sail is not much slower than a 50ft boat with 14 T and 139m2 sail?

    Even if we do as you suggest and consider the trade winds (medium to strong) and downwind sailing, a boat like the Motiva 49 with 16k wind can sail near hull speed , I mean around 7.5K (the last knot is hard to get and will need more wind). And I agree that downwind, with this kind of boat, if you have lots of wind, there is no advantage in hoisting more sail than the one needed to reach near hull limit. The boat will only go deeper in the water and make a bigger front wave.

    But on the First 50 (49,2ft) with 16k wind you will sail downwind at over 9k (over hull speed) and if you have more wind, as it usually is the case, the boat can easily make over 10k. That’s a huge difference of speed.

    And even following the trade winds if you Cross North or South you have the droldrums with very weak winds, and here you would have to use the Motiva big diesel tanks.

    But cruising, offshore or not, trade winds are only a small part of a cruiser life and out of those, every cruiser knows that even on a fast boat he will have to motor at least ¼ of the time. On a boat like the Motiva, unless that cruiser has the patience to cruise at 3 or 4k, he will use the engine a lot more than half the time.

    (I know, I have sailed a lot on a Steel 50ft boat)

    A boat like the First 50 at 50º off the wind, only needs an 8k wind to make 7k. A boat like the Motiva will need, to do the same, 14k of wind.

    If we were talking about the Oceanis 50, that is lighter and carries less sail than the First, the sailing speed would be probably 1k less on all sailing positions.

    That’s also a huge difference to the Motiva 49.


    You are also saying:

    I believe you are right, but the fact is that a 50ft production steel boat is a lot more expensive than a modern production fiberglass boat.

    The Motiva 49 is much more expensive (2x?) than the Beneteaus, as are all production metal boats (steel or alluminium) that I know of, comparing with similar sized boats with an equivalent interior quality.

    Mike, I don´t want to say with this that the Motiva is a bad boat (it is not), what I want to say is that there are different kinds of sailors that value the different qualities of a boat from different perspectives and personal tastes. What I am saying is that a sailor that would consider a Motiva as a cruising boat, would never consider a First and that one, who is undecided between an Oceanis or a First would not be interested in a Motiva.

    Different sailors, different boats:cool: .

    That’s why I am saying that if you can only analyse a boat from a personal point of view that can not be separated from your own particular tastes, you should only analyse the kind of boats that you like.

    Comparing the Motiva with the First would be a senseless exercise, as it would be to compare the sailing qualities of the Motiva having as measure the ones from the First, or comparing the sea motion of the First having as measure the ones from the Motiva.

    If you do that, all heavy boats will be very slow boats and uninteresting boats to sail and all the light boats would have a very uncomfortable motion at sea.

    For analysing a boat, you have to compare it and have as measure boats with the same characteristics. If you choose to analyse a light and fast offshore cruiser, you should analyse it from the perspective of the sailors that are cut for these types of boats (or the other way around:p ). It makes not any sense to compare it with a heavy boat, a boat that would not raise any interest to those sailors.
     

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    Last edited: Nov 9, 2007
  13. MikeJohns
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    MikeJohns Senior Member

    Performance of any displacement boat of reasonable hull shape depends absolutely on LWL SA/D and SA/WSA and as I said the ability to carry that sail area.

    The Cruising load is the great equalizer with a disproportionate effect on the performance ratios for lighter vessels. You must analyze the cruising boat in the loaded condition and that means with all additional equipment aboard not just stores. The manufacturers curves are overly optimistic to take very seriously for this purpose. Ditto for the magazine reviews of vessels.
     
  14. Vega
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    Vega Senior Member

    Yes I agree. But modern light cruisers, like the ones I have posted are made to go, on the right conditions, over hull speed, quite easily. For doing that they have a specific hull shape, with big transoms, flattish hulls and fine entries. I hope that you find this hull shape “reasonable”, after all it is the shape of most modern cruisers. They work very well, providing what they are designed for: Speed

    Again, I agree with you. These light and fast cruisers are not for the sailors that like to cruise with a lot of stuff, the kind that never throw anything away, because one day it can become handy.

    The need to travel light to travel fast and enjoy the ride is common to light cruisers, cats ….sport cars and motorcycles. It is not for every sailor really, but certainly there are a lot of sailors that enjoy that kind of simple life, a life perhaps not with all comforts, but with the ultimate pleasure: Sailing fast, while cruising,.


    Yes I know. I have made allowances. I have not quoted the numbers the manufacturer provided, I have taken away almost 1k of speed (and that’s a lot).

    About the magazines this time I didn’t even have a look:D . I don’t need, I know sailors that sail these kinds of boats; after all, most production cruisers are light boats. I have one of them and I know very well what to expect from it.

    About hull speed, the one for my boat is 7.35k. I can guarantee that downwind, on those typical trade winds (after all we have the Portuguese trade winds along our shore:) ), my boat, with 25 to 35k of wind sails well over hull speed (from 8 to well over 9K). And I am not talking of surfing. Last year I have made a leg with 70 Nm averaging 8k (and on the first hour and a half I didn’t make more than 6.5k. And I am not talking of a boat in minimum sailing condition, but on a boat equipped for cruising one and a half months and to make thousands of miles. Of course, this doesn’t mean that the boat is near Max load. I don’t like to travel with lots of dead weight around:cool: .

    Anyway, there are lots of sailors on this forum that can tell you what the speed is that a modern light weight 50ft cruiser will make on the Trade Winds.

    Condor, are you there:) ? Can you tell us at what speed your boat goes downwind with 25 to 35k?

    António, and what about your boat? I bet that you have a lot of experience sailing downwind on these conditions. Tell us about it;) .

    Cheers
     

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  15. Antonio Alcalá
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    Antonio Alcalá Ocean Yachtmaster

    Vega, I didn´t want talk about my sailboat because I´prefer to talk about anothers with less LOA, they are most easier to find in any harbour. Anyway If you want to talk about my Beneteau 473, I will.
     
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