The Yard Guys

[smackdaddy]

Originally Posted by colemj

Mark

Woah! A calculator with a steering wheel! I gotta get me one of those!

Do you think they have a Doublé Wheel Polipop model?

[Polux]

Originally Posted by Exile

I don't why I keep doing this to myself, but exactly how does the stability of a 37' boat vs. one that's 50' have anything to do with this thread? Isn't it more about the noob who is wondering whether to buy the heavy bluewater boat vs. the newer lightweight production boat? If so, don't we want to compare, say, the stability of an approx. 40' IP, for example, to perhaps Smack's 40' Hunter??

Just thinkin' out loud here . . . .

Well, if you want a boat to sail offshore and to cross Oceans and if in your budget will fit a Island Packet 37 and a Jeanneau 50DS (or any other mass production sailboat of about that size) the question that arises is what is the better boat to do it, in what regards, seaworthiness, comfort, living space, storage, carrying load ability, tankage and speed. It seems that in what regards budget you should compare the options regarding boats with the same price tag.

[avb3]

Originally Posted by smackdaddy

He'll never believe you. He's got calculators.

Wonder if you ever figured out that the Oyster you so proudly showed us was just being prepped properly?

You never did reveal if you actually ever had your boat done, if you did, were you there to see it, or have you seen other boats getting bottom jobs that were prepped. It is quite instructive to actually watch what happens, as opposed to just reading it on the internet, if you never had any exposure to that before. One learns a lot by hanging around with the yard guys for awhile. Cheapest lessons come when you buy them lunch.

Conveniently you ignored to answer that question three times. Is there a reason?

[Polux]

Originally Posted by neilpride

....and to be honest a breaking freaking 20 ft wave can knock down easy a Ds 50 same as a Ip 38..[/I]

Yes, but what I had said from the beginning is that it will be needed a bigger wave to capsize a Jeanneau 50DS, or if you want to put it in another way, a breaking wave that will for sure capsize a IP38 may not capsize a Jeanneau 50DS. It is about that I have been talking about,the energy needed to capsize each boat, that is bigger on the Jeanneau case.

Originally Posted by neilpride

So if i understand, ft by ft, keel by keel, pound by pound a hig AVS boat is harder to roll than a low AVS boat, this part is what i keep it to me...
Back to the Yard guys.

Length, keel (CG) and weight certainly have to do with a boat stability but you forgot an important factor: Everything being the same beamier boats will be harder to capsize and the best example you have are multihulls that rely on beam for most of its stability.

A beamier boat with the same keel weight and CG will have probably a lower AVS than a narrow one with the same characteristics but will need more energy to be capsized or rolled.

Nothing of this is simple and each boat has to be accessed separately.

The STIX as you can saw with the case of the smaller and bigger IP can give weird results and that's why boat manufactures don't give a dam about it and most don't use it on the boat information. It should have already be revised. The biggest problem is that the formula diminishes the STIX to boats with a bigger sail area, as if the sail area could not be easily reefed or the sails could not be changed by storm sails on demanding situations. That explains why a boat with a very small sail area (and that sails very badly) like the IP 38 can have a much better STIX number than much bigger and more modern Island Packets, that sail much better and have a bigger sail area.

[avb3]

Originally Posted by colemj

avb3, run the numbers for this through your famous equation, compare the results to your Flicka 20 (they will be very unfavorable, with the Flicka far more "stable") - then ask yourself which do you REALLY think will be more stable in 50kt winds and 30' seas?

Like Polux is trying to educate you - energy is the key, and your equations are only good for comparing very similar boats.

Mark

Actually the Flicka does very well on that versus an Island Packet 38 as the reference boat. Capsize ratio Flicka 1.76 vs IP38 1.83. But never mind that you think that is unfavorable (your wrong, lower is better), no knowledgeable person considers the Flicka unseaworthy.

Tiny, cramped, not something most of us would WANT to cross long passages with, but very capable of doing so.

Now, I wonder how closely the conditions that IP38 mentioned earlier was in (Force 12) compared to this?

http://youtu.be/LwKXfc_a4Ag

Sorry for the music, not my choice.

There is NO boat I would want to be out in with that. Apparently it was on trip north from California to Canada. After the ship sailed into harbour local authorities carried out an inspection and sent it to a shipyard for repairs. The bow was full of water, the hull cracked in many places, half the stuff you can see on deck was missing, and the ship was only a year old so it didn't simply break up into several pieces.

That captain should have been fired... the rest of the boats stayed at anchor waiting for a better weather window.

[Exile]

Originally Posted by Polux

Well, if you want a boat to sail offshore and to cross Oceans and if in your budget will fit a Island Packet 37 and a Jeanneau 50DS (or any other mass production sailboat of about that size) the question that arises is what is the better boat to do it, in what regards, seaworthiness, comfort, living space, storage, carrying load ability, tankage and speed. It seems that in what regards budget you should compare the options regarding boats with the same price tag.

If it's the much broader question of the "better boat" for long-distance cruising, your additional criteria arguably makes your point more plausible. But you also have to consider the drawbacks of a larger boat, most notably ongoing expense. But the discussion was focused on seaworthiness, which inevitably brought up Stix & Avs -- for better or worse. It sounded to me like you had to add 13' to achieve similar specs. I would think most prospective buyers would be confining their search to smaller parameters when it comes to size. In fact, it may be fair to say that most on a budget might be looking for the smallest boat they can find that would meet their needs. Since you seem to have a command of the data, it would be helpful for you to compare similarly-sized boats that fairly represent the two broad categories that this thread seems to be mainly about. We are well aware of many of the pros & cons, but seaworthiness (however defined) still remains rather elusive.

[neilpride]

At least the Ip can hold lots of wáter in the bilge , the Ds 50 cant say the same.

[weavis]

Originally Posted by avb3

http://youtu.be/LwKXfc_a4Ag

Sorry for the music, not my choice.
.

Better music

https://www.youtube.com/watch?v=c8-PXdndsWE

[Polux]

Originally Posted by avb3

Actually the Flicka does very well on that versus an Island Packet 38 as the reference boat. Capsize ratio Flicka 1.76 vs IP38 1.83. But never mind that you think that is unfavorable (your wrong, lower is better), no knowledgeable person considers the Flicka unseaworthy.
...

You are really convinced that the energy needed (size of the breaking wave) to capsize a 20ft Flicka with 6000 pounds of displacement and 1800 pounds of ballast as anything to do with the energy needed to capsize a IP 38 with 21 500 pounds of displacement and 10 000lbs of ballast?

I have already explained to you that the capsize ratio is a relative number. In the case of the Flicka relative to other 20ft boats with about the same displacement. I am not saying that it deserves any confidence, I mean the capsize ratio, but at least try to look at it the right way.

[Polux]

Originally Posted by Exile

I.. But you also have to consider the drawbacks of a larger boat, most notably ongoing expense.

Yes I agree.

Originally Posted by Exile

I would think most prospective buyers would be confining their search to smaller parameters when it comes to size. In fact, it may be fair to say that most on a budget might be looking for the smallest boat they can find that would meet their needs.

This is not true, you have just to look to the increasing size of the average new cruising boats. In Europe, were most of then are situated, most of the new cruising boats that are actually cruising are bigger than my 41ft sailboat and the tendency is to increase.

Why would someone buy a much smaller sailboat, even considering that the seaworthiness is the same, if they can have for the same price a boat with much more living space and much faster? The reality shows that they chose the bigger boat their budget can afford, or close to that, I mean in what regards the majority of cruisers.

Regarding those that enjoy the fun of sailing as much of cruising the choice can be different. They can choose not to have all that comfort and space trading that for a smaller but equally expensive performance boat that will actually be faster than the bigger boat and be more fun to sail.

Off course we are talking about sailors on a budget. If you have not a budget the chances are they are buying something like a new Amel, a new Oyster or a new XC yacht, not a small luxury heavy cruiser. That is the reason they are disappearing from the market. Many brands that used to have smaller medium height luxury cruisers have now only medium to big models. There is very few buying them.

[Exile]

Originally Posted by avb3

Wonder if you ever figured out that the Oyster you so proudly showed us was just being prepped properly?

You never did reveal if you actually ever had your boat done, if you did, were you there to see it, or have you seen other boats getting bottom jobs that were prepped. It is quite instructive to actually watch what happens, as opposed to just reading it on the internet, if you never had any exposure to that before. One learns a lot by hanging around with the yard guys for awhile. Cheapest lessons come when you buy them lunch.

Conveniently you ignored to answer that question three times. Is there a reason?

Usually the non-response IS the answer but this time Smack may just be anxiously awaiting a reply from the yard he e-mailed in England to confirm that what they did to the Oyster did in fact amount to "repairs" & "maintenance." I've been told that they actually speak English over in England so hopefully they'll get back to him.

But of course we can all agree that the type of minor filling & fairing work that is often part of routine prep for new bottom paint can be deemed "repairs" & "maintenance," but that type of work is entirely distinguishable from the types of major structural repairs to keels & rudders that Smack was hoping for. Of course, it doesn't mean there aren't Oysters or other fine boats that haven't needed structural repairs for whatever reason.

[avb3]

Originally Posted by Polux

You are really convinced that the energy needed (size of the breaking wave) to capsize a 20ft Flicka with 6000 pounds of displacement and 1800 pounds of ballast as anything to do with the energy needed to capsize a IP 38 with 21 500 pounds of displacement and 10 000lbs of ballast?

I have already explained to you that the capsize ratio is a relative number. In the case of the Flicka relative to other 20ft boats with about the same displacement. I am not saying that it deserves any confidence, I mean the capsize ratio, but at least try to look at it the right way.

Your explanation as to the CR being a relative number to similar boats, seems to be different than what others describe it at. Perhaps you can advise as to why this may be.

From this website (reference to assertions made are always good). It is a good overview of CR.

CAPSIZE RATIO: Some years ago the technical committee of the Cruising Club of America came up with a simple formula to determine if a boat had blue water capability. The CR compares beam with displacement since excess beam contributes to capsize and heavy displacement reduces capsize vulnerability. The formula is the maximum beam divided by the cube root of the displacement in cubic feet:
Capsize Ratio = Beam/Displacement.333.

The displacement in cubic feet can be found by dividing the displacement in pounds by 64.

The boat is acceptable if the result of the calculation is 2.0 or less but, of course, the lower the better. For example, a 12 meter yacht of 60,000 lbs displacement and 12 foot beam will have a CR Number of 1.23, so would be considered very safe from capsize. A contemporary light displacement yacht, such as a Beneteau 311 (7716 lbs, 10'7" beam) has a CR number of 2.14. Based on the formula, while a fine coastal cruiser, such a yacht may not be the best choice for ocean passages.

I've also stated it is JUST a screening tool, but one that is worth looking at depending on your purpose. Many won't care. But to dismiss it outright is also not appropriate.

How often has it been said boats are always compromises. You prefer fast coastal boats, which may or may not be appropriate for ocean voyages. Others prefer more of a comfortable and roomier interior, and will not place as high as value on the boat being ideal for ocean passages. Some are in between that.

For a screening tool to be useful, it does help to understand it has limitations, but it is a good first place to look at, if ocean passages are part of your plan.

[colemj]

Originally Posted by avb3

Actually the Flicka does very well on that versus an Island Packet 38 as the reference boat. Capsize ratio Flicka 1.76 vs IP38 1.83. But never mind that you think that is unfavorable (your wrong, lower is better), no knowledgeable person considers the Flicka unseaworthy.

Please step away from your Doublé Wheel Polipop and try to understand some basic physics.

If you could understand basic english comprehension, you would have easily read my posting as knowing which direction the stability numbers use.

No knowledgeable person considers the Flicka more seaworthy than the largest cruise ship in the world, even though the Flicka's capsize ratio is better according to your calculator.

It is all about energy, on which Polux is fruitlessly trying to educate you. That calculator you so slavishly hold to is only useful for certain designs of boats that are very closely related.

If you don't believe me, ask yourself why multihulls are not included in these calculations. Ask yourself if you think the IP38 really does have a greater stability than an IP44. If the Flicka really is more stable than the Jeanneau 50DS.

One can lead the horse to water...

Mark

[colemj]

Originally Posted by avb3

I've also stated it is JUST a screening tool, but one that is worth looking at depending on your purpose. Many won't care. But to dismiss it outright is also not appropriate.

Nobody has dismissed it. They are trying to get you to understand that you do not understand how to apply it. This formula just breaks down when comparing boats of much different designs and sizes. It is a screening tool only for very similar size and designs of boats (which made sense back in the glory days of the CCA).

Again, run a mulithull's numbers through it and make judgements.

Mark

[Polux]

Originally Posted by avb3

Your explanation as to the CR being a relative number to similar boats, seems to be different than what others describe it at. Perhaps you can advise as to why this may be.

From this website (reference to assertions made are always good). It is a good overview of CR.

CAPSIZE RATIO: Some years ago the technical committee of the Cruising Club of America came up with a simple formula to determine if a boat had blue water capability. The CR compares beam with displacement since excess beam contributes to capsize and heavy displacement reduces capsize vulnerability. The formula is the maximum beam divided by the cube root of the displacement in cubic feet:
Capsize Ratio = Beam/Displacement.333.

The displacement in cubic feet can be found by dividing the displacement in pounds by 64.

The boat is acceptable if the result of the calculation is 2.0 or less but, of course, the lower the better. For example, a 12 meter yacht of 60,000 lbs displacement and 12 foot beam will have a CR Number of 1.23, so would be considered very safe from capsize. A contemporary light displacement yacht, such as a Beneteau 311 (7716 lbs, 10'7" beam) has a CR number of 2.14. Based on the formula, while a fine coastal cruiser, such a yacht may not be the best choice for ocean passages.

I've also stated it is JUST a screening tool, but one that is worth looking at depending on your purpose. Many won't care. But to dismiss it outright is also not appropriate.
....

For a screening tool to be useful, it does help to understand it has limitations, but it is a good first place to look at, if ocean passages are part of your plan.

As obviously a 20ft Flicka with 6000 pounds of displacement and 1800 pounds would be far easier to capsize then a IP 38 with 21 500 pounds of displacement and 10 000lbs of ballast, even if your calculator attributes a better number to the 20ft Flicka, you can choose between considering it completely unfitted for any kind of calculations, (even among similarly typed boats the ones for what that calculator is meant for), or just consider that those numbers are relative and should only mean anything when referring of boats with about the same size and displacement. Your choice

Originally Posted by avb3

How often has it been said boats are always compromises. You prefer fast coastal boats, which may or may not be appropriate for ocean voyages. Others prefer more of a comfortable and roomier interior, and will not place as high as value on the boat being ideal for ocean passages. Some are in between that.

Now I don't follow you at all. What has this to do with you saying that a small 20ft Flicka is more difficult to capsize than a IP 38, or it is a better offshore boat? Why do you says I prefer faster coastal boats? Certainly I prefer them faster but an offshore boat does not have to be slow. We were talking about a Jeanneau 50DS. Do you think that is a coastal boat?

what people prefer or not in what regards boats for cruising and making ocean passages, regarding recent boats, can be seen on what they chose to make the ARC and I would say that most chose precisely boats like the Jeanneau 50DS, that size and all.

An I can understand them very well regarding that choice versus the choice of a boat like the IP370: not only more space, more storage in the freezer, more storage everywhere, bigger tankage, more comfortable motion due to a much bigger LWL, more seaworthy due to size, more living space, incomparably faster and that has not only to due with safety but with comfort also:
There is an IP 38 doing the ARC, they are about 3 days from arriving while most of the boats the type of the Jeanneau 50DS arrived already at 4 days or so. More a week at sea on a passage? Do you call that comfortable?