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Old 05-30-2016, 12:51 AM   #61
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Originally Posted by MRRiley View Post
I'm honestly not trying to be contrary here, but here is a hull lay out schematic for a Westsail 32

WESTSAIL 32 sailboat specifications and details on sailboatdata.com

Even a brief glance can allow one to determine that generally, they have aprox. half of their volume submerged with their full keel.

When determining the buoyancy and gravity calculations, which then determine meta-centic height, it's not tough to see why they in fact, may have a class A certification.

Of course it's not as easy as a quick glance at a line drawing, but the principle of the mathematics demonstrated in the video above remain valid.
in fact, may have a class A certification? Do they, in fact, have one? An Oceanis 38, just to compare a Beneteau line to their ST powerboat line, has an A for 8, B for 9, C for 10 passengers. An Oceanis 35 is A for 6, B for 8, C for 10. An Oceanis 31 is B for 6, C for 8 and D for 10. So, I can believe a Westsail having an A for 4 or 6 passengers.

However, we're way off topic, as the topic was powerboats, which is where my knowledge is. I admit to very little sailboat knowledge. I've referred the OP to a couple of very useful sources of information. One of those is written by Nordhavn and directly applicable to the type and size boats he's looking at.
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Old 05-30-2016, 12:56 AM   #62
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For a quick visualization try this:

Put your left had above a table to, your right below. Then separate them to approximate in any scale you choose, for the distance between the bottom of the keel on a Westail 32 and the top of the cabin, assuming the rig weight is negligible. Do the same thing for a a normal size trawler with a fly bridge.

This might illustrate why the physics and stability favor small sailing vessels vice small power boats of the same size.

I'm not trying to derail the conversation, in fact the sail example as posted by the thread originator, my point was why sailboats in general are more stable, hence receive higher EU ratings than power boats

My original point was to try to further the understanding of stability in general. My regrets if my effort was in error.
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Old 05-30-2016, 01:09 AM   #63
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For a quick visualization try this:
I'm not trying to visualize as I don't have the need, but you said a Westsail may have an A. I asked a simple question of does it? I'm not arguing, just asking as you were unclear, at least to me.

I then gave examples of smaller sailboats that are CE A, down to 35'. I can give examples of 44' powerboats that are CE A. The smallest size trawler KK builds today is 44' and they say they can get it categorized as CE A. I prefer not to speculate or visualize or get into a discussion of boat design, but have gone to actual boats and shown what they are.
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Old 05-30-2016, 01:19 AM   #64
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I gave examples of smaller sailboats that are CE A, down to 35'. I can give examples of 44' powerboats that are CE A. The smallest size trawler KK builds today is 44' and they say they can get it categorized as CE A. I prefer not to speculate or visualize or get into a discussion of boat design, but have gone to actual boats and shown what they are.
While the specific examples you refer to tend reinforce the data I provided, that smaller sailboats are generally more stable than smaller power boats, I really don't know or care if a Westsail 32 has an A rating or other.

The point is, if I may reaffirm, is that the whole question is based on the physics and specifics of the mathematics of the hull form and deck form in question.

A Nordhavn 46 with a fly bridge is less stable than one with out. Personal choices aside since calculations will prove it.

Again, my only observation was that the math of forces acting on any vessel will determine it's stability, personal opinion aside.
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Old 05-30-2016, 07:45 AM   #65
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While the specific examples you refer to tend reinforce the data I provided, that smaller sailboats are generally more stable than smaller power boats, I really don't know or care if a Westsail 32 has an A rating or other.

The point is, if I may reaffirm, is that the whole question is based on the physics and specifics of the mathematics of the hull form and deck form in question.

A Nordhavn 46 with a fly bridge is less stable than one with out. Personal choices aside since calculations will prove it.

Again, my only observation was that the math of forces acting on any vessel will determine it's stability, personal opinion aside.
You are greatly oversimplifying the elements of determining category and there are many more factors than stability. You may not care about the Westsail but you certainly made an effort to imply it was an A.

Now back to the OP and KK vs. Nordhavn. If I was concerned about rough seas and the capability of the boat, then whether a KK or a Nordhavn, then I'd absolutely want stabilizers.
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Old 05-30-2016, 07:59 AM   #66
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sure do like that 36' kk manatee. wish they still made them. unusual looking but very comfy layout.
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Old 05-30-2016, 08:46 AM   #67
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Old 05-30-2016, 08:52 AM   #68
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If I was concerned about rough seas and the capability of the boat, then whether a KK or a Nordhavn, then I'd absolutely want stabilizers.

Why?

Stabilizers do not impart stability, they attenuate motion.

To clarify, the Westsail 32 was put forth by the OP as an A rated boat, nobody else. A B or C Euro ratings don't mean squat and neither does building a 79' or larger boat to class. Brand new boats built "to class" abound with serious flaws not reported by the class surveyor. Yogi was A rated I believe.

But to add yet another tangent to this already fragmented thread are you seriously arguing that sailboats of any size are less stable than power boats?
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Old 05-30-2016, 09:43 AM   #69
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A B or C Euro ratings don't mean squat and neither does building a 79' or larger boat to class. Brand new boats built "to class" abound with serious flaws not reported by the class surveyor. Yogi was A rated I believe.

But to add yet another tangent to this already fragmented thread are you seriously arguing that sailboats of any size are less stable than power boats?
I never argued that. In fact, I showed examples of smaller sailboats that met category A standards.

As to saying A, B or C doesn't mean squat nor does class, I strongly disagree with that. None assure the safety of the boat. Euro categories on production boats say zero about quality of build, just design. As to Class, I do believe it's a good indicator, but grant not perfect. There is also a lot of argument taking place today over the different class societies. There are over 50 class societies and 12 of those are members of IACS. Some are better than others.

As to Yogi, there are a lot of unanswered questions. Speed, how the water ingress occurred, how it got into the steering area, the doors open between the beach areas, why the bilge pumps either weren't used or were inadequate. ABS was the Class Society. I have no idea what caused Yogi to sink. Stability did not appear to be an issue. Although ABS hasn't been targeted as not adequately surveying in this situation, they were also the Society on a recent sinking of a South American vessel off Florida and no cause has been determined in that sinking.

Was there something missed and inherently wrong with Yogi or were there issues encountered outside the norm including failure of crew to exercise normal precautions such as insuring doors between the compartments were closed. We'll never know.

Class, category, ABYC, Insurance surveys, and all the rest are not guarantees or sole indicators of the safety of a boat. I have been through the Class process. My limited experience in doing so is that it provided me assurance that certain things were reviewed that otherwise might not have been. However, in this case it was a boat model that has been classed many times so the builder was already complying. Still a double check and certain additional procedures. I have also known class societies to refuse to sign off on boats that the builder had guaranteed the buyer would be classed by that society, so I do know that in some cases, some societies do their work diligently.

Category is just one indicator of the design characteristics of a boat. Nothing more. It is absolutely not an indicator of the build quality of a specific boat. It may indicate a designed seaworthiness but the actual may be different on a specific boat.
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Old 05-30-2016, 10:22 AM   #70
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You are greatly oversimplifying the elements of determining category and there are many more factors than stability. You may not care about the Westsail but you certainly made an effort to imply it was an A.
Once again, I'm not trying to be argumentative here, but I made no reference to the determination of category except to say that I (thought, believed, wondered) that Eu classification was based on the numbers.

Stability is an issue of which all boaters should have some reasonable understanding. Vessel type, use, and classification have little bearing on the reality of the physics of the matter.

In my opinion. (Added for the PC crowd).
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Old 05-31-2016, 05:13 AM   #71
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"Stability is an issue of which all boaters should have some reasonable understanding. Vessel type, use, and classification have little bearing on the reality of the physics of the matter."

For any small boat , the only survival technique is to NOT be there.

The USN avoids winter storms , which are milder than hurricanes .

If a carrier gets out of the way it would be wise for a 50 fter to do the same.
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Old 05-31-2016, 09:19 AM   #72
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I doubt very much that a Westsail 32 would have a class A rating...
My Catalina 36 Sailboat had a Class A CE rating - I would expect the Westsail 32 (built as a blue water cruiser) to be Class A as well.

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Old 05-31-2016, 09:35 AM   #73
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I looked at the Nordhavn 46 and researched it extensively while on my search for a passagemaker. The living space was a bit small for the size of vessel - but that reflects its focus on seaworthiness. I was very impressed and would expect it to be one of the most capable ocean boats in its size range.

I never looked at a Krogen 42 since it was smaller than the range I was looking in. I ended up with the Krogen 54 which has a nice combination of living space and ability to handle big seas. The worst I've had her in so far is 50kt gusting to 56kt and 5.5m (18') seas. She took plenty of white water over the pilot house but not once did we bury the bow or see any green water on deck.

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Old 05-31-2016, 11:40 AM   #74
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The Westsail 32 has a very good reputation has a Blue Water Cruiser. It would not have a CE rating since the last boats were built a couple of decades prior to there being a CE rating.

Later,
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Old 05-31-2016, 12:25 PM   #75
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As well as comparing twenty + year old designs and construction techniques that have been changed/abandoned by the builders, prior upkeep may well be the deciding factor when comparing old boats.

A better comparison would be the newer offerings from each builder, say comparing a KK 52 to a N52. Or KK 44 to a N 43. Price enters into it as well on new builds. Surprisingly to me comparing the two 52s a few years ago showed a clear advantage to the N, don't know if this is the case today.
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Old 05-31-2016, 03:41 PM   #76
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I doubt very much that a Westsail 32 would have a class A rating. On the other hand, I'm not familiar with any boat over 75' with less than an A rating, although I'm sure there are some exceptions.

What the ratings mean is that the design of the boat meets criteria established by the EU for the purposes described in each of the categories. It's that simple. It doesn't mean you're going to be safe or unsafe in various conditions, just that the boat meets the basic design criteria to handle those conditions. However, there are many other factors to being safe on the water. The classification societies do address far more factors. ABS though, as an example, doesn't class anything under 79'.

Nordhavn has a very good write up on this subject.

Welcome to Nordhavn.com - Power Thats Oceans Apart
Thanks for the link. Westsails were built in the USA so likely are noit rated that way but they have demonstrated the ability to survive the worst the sea has to offer many times over so I assumed they were at least equal to that EU standard.
Isnt the KK hull design similiar to a sailboat hull? At least they look similiar to me
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Old 05-31-2016, 04:04 PM   #77
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"Stability is an issue of which all boaters should have some reasonable understanding. Vessel type, use, and classification have little bearing on the reality of the physics of the matter."

For any small boat , the only survival technique is to NOT be there.

The USN avoids winter storms , which are milder than hurricanes .

If a carrier gets out of the way it would be wise for a 50 fter to do the same.
The issue is that a 6-9knt boat has zero chance of out running a storm or even stepping aside to let it pass unless one has a couple of days notice. The options are only one rig for foul weather and ride her out. Is there anyone out there with blue water experiance that hasne been caught by a storm with there pants down? My experiance is sometimes they come out of no where and many small craft just don't have modern state of the art electronics.
A carrier can hit 40knts or more, a little faster than any kk or Nordhavn
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Old 05-31-2016, 04:14 PM   #78
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The issue is that a 6-9knt boat has zero chance of out running a storm or even stepping aside to let it pass unless one has a couple of days notice. The options are only one rig for foul weather and ride her out. Is there anyone out there with blue water experiance that hasne been caught by a storm with there pants down? My experiance is sometimes they come out of no where and many small craft just don't have modern state of the art electronics.
A carrier can hit 40knts or more, a little faster than any kk or Nordhavn
Learn a bit about weather and sidestepping storms in slow boats is not out of the question if you can get current, reliable weather data.
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Old 05-31-2016, 04:16 PM   #79
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While the specific examples you refer to tend reinforce the data I provided, that smaller sailboats are generally more stable than smaller power boats, I really don't know or care if a Westsail 32 has an A rating or other.

The point is, if I may reaffirm, is that the whole question is based on the physics and specifics of the mathematics of the hull form and deck form in question.

A Nordhavn 46 with a fly bridge is less stable than one with out. Personal choices aside since calculations will prove it.

Again, my only observation was that the math of forces acting on any vessel will determine it's stability, personal opinion aside.
Your comparison of a Nordhavn with or without a flybridge is with the knowledge of whether ballast was added to compensate?

And of course you know stability and survivability aren't directly related?
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Old 05-31-2016, 04:17 PM   #80
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I looked at the Nordhavn 46 and researched it extensively while on my search for a passagemaker. The living space was a bit small for the size of vessel - but that reflects its focus on seaworthiness. I was very impressed and would expect it to be one of the most capable ocean boats in its size range.

I never looked at a Krogen 42 since it was smaller than the range I was looking in. I ended up with the Krogen 54 which has a nice combination of living space and ability to handle big seas. The worst I've had her in so far is 50kt gusting to 56kt and 5.5m (18') seas. She took plenty of white water over the pilot house but not once did we bury the bow or see any green water on deck.

Richard
bury the bow, brings back fifty year old memories of what i called back then, going submarine. The first time it happened to me I remember thinking, were going submarine wonder how deep we will go?.
The kk 54 is a beautiful vessel tons of room and a good choice. I wish to stay closer to 40 foot as its mostly just me and sometimes a cat. Once in awhile i take friends but kinda only ones with ample boating experiance. A dealer up in Washington keeps trying to steer me towards the kk39.
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