Sunday, November 27, 2022

NEW BEAMIER BAVARIA 46C, AND THE IMPORTANCE OF BEAM IN SAILBOAT PERFORMANCE

                                                                                                                                                                                                                              Bavaria C46

Beamier, is it better? It is not only Bavaria but all main market brands and even most performance cruisers: the new model is always beamier than the previous one, and I wonder how long this tendency, that lasts already for some years, will be possible to maintain.

Bavaria C46
Do beamier sailboats sail better? No, they don't, at least, when the previous boat was already a boat with a big beam. Is the difference significant? Well, while motoring not much (it is easier to put a bigger engine) and while sailing the bigger hull stability will allow bigger sails, but they do not only need bigger sails, as they will always sail slower in light wind conditions and upwind, due to a much bigger wave drag.

Obviously, they design boats this way because cruisers prefer them this way and manufacturers design them to suit the bigger number of customers: most, if they have no money for a catamaran, will buy a monohull as beamier as possible, to have the biggest interior possible.

Bavaria C46
The question is: how much more you can increase the beam on a monohull and still give it a reasonable sail performance? I mean, reasonable for the majority of cruisers because as it is, it's not already reasonable for some.

The C46 is about a foot longer than the C45 (13.95 to 13.60m) but it has a much bigger beam (4.70 to 4.49m). Just to illustrate how this increase in beam has been overwhelming over the last decade, let me remind you that the Bavaria 46 Vision, a good sailboat and a good cruiser, that Bavaria launched a bit more than 10 years ago, had a 4.19m beam.


Bavaria Vision 46
It would be unfair to give you the idea that this increase in the beam in recent boats happens only with Bavaria. If you look at the competition you will see that the same has happened in all recent models.

The Beneteau Oceanis 46.1, which is a bit smaller (13.65 HL) has a 4.5m beam, the Hanse 460 is even beamier with a 4.79m beam, and the Dufour 470 (that has about the same lenght)  has a 4.74 beam.

Jeanneau, among big boat builders, is the brand that increased less the beam of their sailboats:  the SO 490 (that has about the same hull length as the Bavaria C46) has a 4.49m beam, less 29cm, the same beam that had the previous Bavaria C45.

Bavaria Vision 46
Beam and narrow entries are far from being the only factors in what regards sailboat performance, but excessive beam is detrimental to overall sail performance.

Regarding the ideal beam for overall sail performance,  and also, what is the reasonable trade-off in beam increase to allow for a bigger cruiser interior, without losing too much sailing performance, nothing better than to look at the typical beam of racers, and performance cruisers, I mean, not racers or cruisers strongly optimized for a given point of sail (upwind or downwind), but all around good performers.

TP52
Among racers, we can look, as a reference, to a bigger TP52 that has a 15.85m HL and a 4.43m beam or to a bigger Swan 50 club racer that has a 4.20m beam. If we look at performance cruisers, we can take as a reference the Dehler 46SQ, with about the same size as the New Bavaria C46, and a 4.38m beam, the smaller Salona 46 (13.50 HL) with a 4.20m beam, or the new J45 with 4.25 beam.

Bavaria did not release much data about the new C46, but they said both boats would have the same standard sail area (115m2). The C46 is considerably beamier, just a bit longer, and probably heavier and both boats are designed by Cossutti, so if you want a boat with a bigger interior, wait for the new C46; if you want a boat that sails better, take the opportunity to buy one of the last C45, because they usually lower the price for the last boats of a given model.

The C45 had some youth problems, that are already solved, and it is a good boat with an innovative structure, that makes it one of the stiffer (if not the stiffest) among the competition.

I don´t know if they will maintain that structure on the C46 because they didn´t use it on the newer C42. The truth is that it makes the boat better, but is more expensive and when that is the choice, money is almost always more important, especially in parts of the boat you don't see. I doubt they will maintain that structure on the C46. Unfortunately, the rule in mass-produced boats is always to adopt the less costly solution.

https://interestingsailboats.blogspot.com/2017/12/all-about-beautiful-new-bavaria-c45.html

9 comments:

  1. These boats are much more difficult to med moor than older boats, but that may be driver errors. I watch this every day. Also, they would be fine for coastal cruising but mid-ocean with large following seas would require multiple backup autopilots...

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  2. Hi Rob,

    Regarding sailing in the trade winds with following seas I disagree. In fact these boats are maximized for those conditions, have a good directional stability and roll much less.

    In fact they have in what regards hull design, especially in what regards beam and transom design, much to do with solo racers optimized for those conditions, like IMOCA or class40 racing boats, and they are designed like that partly to be easier to sail.

    Regarding being more difficult to med moor, they have twin rudders and that is good because they have less draft in the rudders and have no risk of hitting the bottom near the quay where it is less deep, but they have more windage and the twin rudder makes them more difficult to maneuver, but every one of them has a bow thruster and some even a transom thruster, so I would say that if you see them with difficulty mooring it is because the skipper does not know what is doing.

    They sail worse upwind and with weak winds and that is its main disadvantage.

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  3. These boats are much more difficult to med moor

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  4. I have already replied to that. The really difficult boats to med moor are old boats with a full keel or a big fin modified keel without bowthrusters, and they were not very usual those days. They are much more difficult to maneuver and have limit steerage while going backwards, and that has nothing to do with having a smaller or a bigger beam.

    Twin rudders offers advantages because they have less draft in the rudders and have no risk of hitting the bottom, near the quay, where it is less deep, but they allow less maneuverability than a single deep spade rudder, but nowadays almost all modern boats have a bow thruster and some even a transom thruster and that makes the maneuver very easy to do, if you know what you are doing.

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  5. I own a C45 for two years. Both C45 and 46 are single rudder boats and drafts of the rudders are quite deep. So you need to be careful when med mooring. On the other hand, I never had difficulty during stern maneuvering.
    Comparing B/D’s of these boats shows interesting results. It’s 0,26 for C45 but 0.20 for C46. So I guess we should expect more heel when sailing C46.

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    Replies
    1. Not necessarily, the new boat is a lot beamier (4,70 to 4.49m) that gives it a lot more hull form stability and will contribute to sail with less heel because hull form stability is generated mostly at low angles of heel.

      Boats with a lot of ballast, like fast cruiser racers or racing boats maximized for upwind sailing, need to heel to generate stability from the ballast, and more the heeling, more the stability that is generated by the ballast.

      What the new boat has worse than the previous one is probably safety stability and AVS, as well as an inferior upwind performance. Most likely it will sail with less heel.

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  6. Exciting to see the new Bavaria 46C and its focus on beam for sailboat performance – a trend shaping the future of sailing!
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  7. Choosing cost over quality often prevails in mass-produced boats like the C46, despite the structural benefits missed out from earlier models.
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  8. Great insights on sailboat design! It's fascinating to consider the balance between beam width and performance, especially when optimizing for versatile cruising without sacrificing sailing efficiency.
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    ReplyDelete