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Old 09-03-2014, 18:57   #256
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Re: Beneteau Sense Quality Issues

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Originally Posted by robert sailor View Post
..The very fact that each boat has to pass this test should indicate that these designs are on the edge of a safety margin. ....
You mean because they are the more demanding boats in what regards safety items: The ability to right itself in flat water without any outside help, the huge positive stability the very good dynamic stability and being unsinkable puts them on the edge of a safety margin

These are among the most seaworthy boats around and have to be since they are designed to sail racing non stop in high latitudes, no matter the weather with a single sailor. That's why the safety measures in what regards a huge positive stability, the ability to re-right itself and being unsinkable.

They are needed not because the boats are on the edge of a safety margin, quite the opposite, but because these boats are designed to sail where and in conditions any other sailboat with a single sailor would be in more danger, on conditions that can be at the edge of a safety margin and where any sailboat can eventually have problems.
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Old 09-03-2014, 19:23   #257
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Originally Posted by Polux View Post

You mean because they are the more demanding boats in what regards safety items: The ability to right itself in flat water without any outside help, the huge positive stability the very good dynamic stability and being unsinkable puts them on the edge of a safety margin

These are among the most seaworthy boats around and have to be since they are designed to sail racing non stop in high latitudes, no matter the weather with a single sailor. That's why the safety measures in what regards a huge positive stability, the ability to re-right itself and being unsinkable.

They are needed not because the boats are on the edge of a safety margin, quite the opposite, but because these boats are designed to sail where and in conditions any other sailboat with a single sailor would be in more danger, on conditions that can be at the edge of a safety margin and where any sailboat can eventually have problems.
I don't understand how you think beamy flat boats are more likely to self right than narrow boats. I must have misunderstood, right? The main way the volvo or open ocean boats self right from inverted are when the keel cants, or with some waves and their 10+ foot heavily ballasted keels.

Comparing the sense, or any other beamy cruisers to that is absurd. Iron keel that is only 3-4 feet long. Most stability is from form stability so if they invert they're likely to stay there.

That said, the sense would be great for 99% of folks who would never be in such conditions. I am sure you could cross oceans in it as well like you could with anything.


Beamy in context of cruising boats is all about accomodations. Making it sound like this improves performance is mainly advertising hyperbole.
No comparison to ocean racers, which are beamy and plane a lot, mostly because of huge sailplans and majority of displacement contained in a lead bulb 10-15 feet below the surface, and minimal accomodations. Opposite of the cruisers, which usually have less than 1/3 ballast ratio, in shallow keels.
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Old 09-03-2014, 19:51   #258
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Re: Beneteau Sense Quality Issues

Comparing a Sense to an Open 60 is sorta like comparing a Toyota Camry with an add-on wing over the boot to a F1 car!

But really, this thread was for a discussion of build quality, not design philosophy and genealogy...

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Old 09-03-2014, 20:27   #259
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Re: Beneteau Sense Quality Issues

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Originally Posted by malbert73 View Post
I don't understand how you think beamy flat boats are more likely to self right than narrow boats. I must have misunderstood, right? The main way the volvo or open ocean boats self right from inverted are when the keel cants, or with some waves and their 10+ foot heavily ballasted keels.
...
Do you see any keel canting?



Again what matters narrow or beamy is the position of the CG. A beamier boat with an equivalent B/D ratio, the same draft and type of keel compared with a narrow boat will have more positive stability (it will need a bigger wave to capsized it) and will have also more negative stability (it will need a bigger wave to put it back on its feet).

Besides the energy needed to capsize the boat another key factor is the proportion between the energy needed to capsize the boat and the energy needed to re-right it, as well as the AVS. You can obtain that measuring the areas for positive and negative stability on a RM curve and making the proportion.

The proportions between the two areas has nothing to do with the boats being beamy or narrow but with the CG position. The same with the AVS.

Let's assume two boats with the same length, same weight, same B/D ratio same type of keel, same draft, one narrow other beamier. Let's assume that the proportion between the negative and positive stability is similar. That should not be very far since they will have a similar CG. Let's assume that proportion is 3 to 1.

The beamier one will have more positive and negative stability, the narrow one less positive stability and less negative stability in about the same proportion. let's say that difference in stability (negative and positive) is of 50%.

Let's assume that the energy needed to capsize the narrower boat is the one of a breaking wave with 2m. That means that the boat would right itself up with a breaking wave of 0.66m, or with a normal non breaking bigger wave.

The wave energy needed to capsize the beamier boat will be bigger. It will correspond to the one of a wave 50% bigger, that means a 3m breaking wave and it will also need the energy of a bigger wave to right itself up, in this case a 1m breaking wave, or a correspondent bigger non breaking wave able to roll the boat till its AVS point.

What is the boat in you would want to be, the one that needs a 3m breaking wave to be capsized and 1m wave to be re-righted or on one that will need a 2m wave to be capsized and a 0.66m wave to be re-righted?

In the end there are boats better or worse designed in what regards final stability and one very important factor is the force the boat is making to re-right itself (proportional to its weight) after a 90 knock out, but beamier or narrow boats are not by itself more or less seaworthy even if in what regards smaller boats beam can be very important to give it an overall better positive stability.

...

Yes jim you are right this should be about build quality but it was not me that have said that the Sense 55 was a boat not suited for offshore work, a marina boat.
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Old 09-03-2014, 20:29   #260
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Re: Beneteau Sense Quality Issues

On the self righting question. I believe I remember marine architect Bill Dixon writing a bit about his Moody 45DS design -- that the triangular hull shape is not stable when inverted. He said that the fine bow and broad stern will not simple roll sideways onto her beam ends like a traditional cruising boat. Instead as heel increases, the narrow bow would tend to submerge and the stern rise causing the boat to "corkscrew" back up.

I may not be remembering this quite right but it would seem to also apply to the Sense.
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Old 09-03-2014, 23:52   #261
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Re: Beneteau Sense Quality Issues

The righting on a Moody DS is mostly about the shape of the large and high topsides assuming it all stays together if rolled.
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Old 10-03-2014, 06:59   #262
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Re: Beneteau Sense Quality Issues

Wheres the mast and sail in that video?
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Old 05-11-2017, 18:46   #263
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Re: Beneteau Sense Quality Issues

It's 2017 now and I'm moving up to a 32 footer with a shoal keel. *My thoughts on Beneteau*. I found the Beneteau's 321 pricing to be attractive comparing to Catalina's 320. So I thought to give them a look. The Bene 321 was very well laid out and the aft cabin was even roomier than the Catalina 320...another thing I liked was the bulb keel(broker said it was lead which is a must for me) instead of the Catalinas " lead wing keel"...the bulb keel would be easier to get off a soft grounding. Another thing I really like about the 321 is the lewmar opening ports instead of the glued on plexi or lexan panels found on most modern boats. A big downer is the build quality of the Beneteau. Spider cracks all over the deck, soft flexible panel to stand on at the helm, leaks into cabin...to the point of puddles on shelves(no port window in this area...Stanchion?? and the biggest sign of cheap build quality is the inferior stanchions and bases that wiggle....the pulpit and the stern rails are most definitely lesser grade than any I've felt ever any any boat. You can actually feel give as you push and pull on them! The broker showed us a beautiful Beneteau 36 center cockpit which was really cool! unfortunately the same issue with inferior hardware. In my opinion, even if you build a boat light for coastal cruising...things like stern rails and stanchions should be better than what Beneteau thinks is ok. After much research I found Beneteau made the 311 with "U' bolts holding the sidestays to the deck...NO CHAINPLATES! Are you kidding me! A child would have more common sense! https://forums.sailboatowners.com/in...-cracked-deck-
damaged-beneteau-311.149627/
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