U20guy2

65- by 32-foot catamaran 3200sqft of living space

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Bizzaro rudder debate. Some here get it. For the others think duty cycle.

"Duty cycle is the proportion of time during which a component, device, or system is operated or stressed.

The more a circuit, machine or component is used, the sooner it will wear out. Therefore, the higher the duty cycle, the shorter the useful life, all other things being equal."

 

 

Great. We're talking about rutters and you have to bring up the doody cycle. I'd prefer to think of catwoman as not having one of those.

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You fellas keep trying to intuit what ought to be deduced; not unlike how HR engineered his cat.

 

Oh so now Newton's 2nd Law is "intuition"?

What cow college did you study injunearrinck at?

 

You fellas keep mistaking a textbook method for deriving how strong a rudder should be for the real-world forces on the rudder.

 

At the risk of repeating myself- this is why clever engineers often build stuff that breaks...

 

FB- Doug

 

Ah, back from 3 days of camping to see the ignorance has not abated. Glad to see you guys can keep the fires burning even if I am not around to stoke them.

 

At the risk of repeating myself, the force/work/energy needed to turn the boat is irrelevant, at least to a estimation to three or four significant digits. You just need the maximum V and the area distribution. There is a physics limit on how much force the water flow can impart to the rudder for a given flow velocity. In practice, virtually all boats will, at one time or another, apply that maximum force to the hull regardless of hull mass. This is because the rudder can almost always be turned at a higher angular rate than the boat can be turned (usually by an order of magnitude or so). So long as the rudder structure is appropriate for that force it will not break no matter what it is attached to. If the structure is not appropriate, it will break at some point no matter what it is attached to.

 

FB-Doug - explain to me the "real world forces on a rudder" that would allow it to impart more force than could be achieved at the max force AOA at a given velocity? The Fmax AOA is the AOA that yields the maximum length vector when the lift and drag components are vector added. How exactly does the rudder exceed that force without more velocity?

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Ever'body's wrong, and I'm amazed no one's pointed it out yet.

 

As Rod stated, the FH has "ruTTers", not "ruDDers". All previous "rudder" posts are irrelevant.

 

Back to proposed sail plan.

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Ah, Catwoman... You 'spose her poo don't stink or maybe she just doesn't poo at all?

Litter box trained, just keep her away from the catnip.

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Bizzaro rudder debate. Some here get it. For the others think duty cycle.

"Duty cycle is the proportion of time during which a component, device, or system is operated or stressed.

The more a circuit, machine or component is used, the sooner it will wear out. Therefore, the higher the duty cycle, the shorter the useful life, all other things being equal."

Perhaps. I was under the impression this discussion in particular was more of a doodie cycle.

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Bizzaro rudder debate. Some here get it. For the others think duty cycle.

"Duty cycle is the proportion of time during which a component, device, or system is operated or stressed.

The more a circuit, machine or component is used, the sooner it will wear out. Therefore, the higher the duty cycle, the shorter the useful life, all other things being equal."

 

I am not sure I understand your point. Obviously, a rudder that needs to be turned to large AOAs on a regular basis will have higher duty cycle. All else equal, a given rudder would have a higher duty cycle on a larger vessel. However, no one here is speculating on when the FH rudder will "wear out." The issue is structural failure from loads exceeding the structural strength in the "new" condition. In general, the rudder components that actually wear from high duty cycle are usually maintenance items (bearings, pintles, gudgeons), and the rudders themselves have no appreciable "wear" at all. If you were building the rudder from material that shows significant fatigue (certain aluminum alloys, or some types of composites in which the resin and fibers were poorly matched), then its duty cycle would be relevant. Building with wood or steel you will find that so long as forces are kept below yield, they maintain their structural properties for millions of cycles. If they exceed yield then they begin to break immediately. All that matters is whether peak loads stay under the yield strength of the rudder.

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Bizzaro rudder debate. Some here get it. For the others think duty cycle.

"Duty cycle is the proportion of time during which a component, device, or system is operated or stressed.

The more a circuit, machine or component is used, the sooner it will wear out. Therefore, the higher the duty cycle, the shorter the useful life, all other things being equal."

Perhaps. I was under the impression this discussion in particular was more of a doodie cycle.

he said doodie

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GOOD LORD

 

my comment was very simple

 

The poster who made the comment I referenced made a tautological statment

Doug disagreed

There is no point disagreeing with a tautological statement so I said so.

 

Feel free to keep explaining why the tautological statement is irrelevant, but I thought I had covered that at the start.

If you think its wrong, you need to go back to the original statement and dissect it a little. :)

 

I think you need to say "tautology" a few more times, cause it'll make you look smarter.

 

I notice you didn't take me up on the 'slap test'.

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Ever'body's wrong, and I'm amazed no one's pointed it out yet.

 

As Rod stated, the FH has "ruTTers", not "ruDDers". All previous "rudder" posts are irrelevant.

 

Back to proposed sail plan.

When a rutter breaks in the middle of a muddy bay, and no one's around to hear it, does it make a sound?

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Ever'body's wrong, and I'm amazed no one's pointed it out yet.

 

As Rod stated, the FH has "ruTTers", not "ruDDers". All previous "rudder" posts are irrelevant.

 

Back to proposed sail plan.

When a rutter breaks in the middle of a muddy bay, and no one's around to hear it, does it make a sound?

sort of a plop. like a doodie

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GOOD LORD

 

my comment was very simple

 

The poster who made the comment I referenced made a tautological statment

Doug disagreed

There is no point disagreeing with a tautological statement so I said so.

 

Feel free to keep explaining why the tautological statement is irrelevant, but I thought I had covered that at the start.

If you think its wrong, you need to go back to the original statement and dissect it a little. :)

 

I think you need to say "tautology" a few more times, cause it'll make you look smarter.

 

I notice you didn't take me up on the 'slap test'.

 

Ahem

This is not a matter of tautology, that would be if the rudder cables broke from being too tight.

 

FB- Doug

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I looked for the FH in the long camera shots today while Oracle beat the snot out of the NZ boat.

Didn't see it though.

Supposed to be pretty windy tomorrow.

 

Tick tick tick.

 

BTW, Catwoman was definitely played by Julie Newmar.

 

Woof !

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GOOD LORD

 

my comment was very simple

 

The poster who made the comment I referenced made a tautological statment

Doug disagreed

There is no point disagreeing with a tautological statement so I said so.

 

Feel free to keep explaining why the tautological statement is irrelevant, but I thought I had covered that at the start.

If you think its wrong, you need to go back to the original statement and dissect it a little. :)

 

I think you need to say "tautology" a few more times, cause it'll make you look smarter.

 

I notice you didn't take me up on the 'slap test'.

 

Ahem

This is not a matter of tautology, that would be if the rudder cables broke from being too tight.

 

FB- Doug

is it my turn to say doodie?

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GOOD LORD

 

my comment was very simple

 

The poster who made the comment I referenced made a tautological statment

Doug disagreed

There is no point disagreeing with a tautological statement so I said so.

 

Feel free to keep explaining why the tautological statement is irrelevant, but I thought I had covered that at the start.

If you think its wrong, you need to go back to the original statement and dissect it a little. :)

 

I think you need to say "tautology" a few more times, cause it'll make you look smarter.

 

I notice you didn't take me up on the 'slap test'.

 

Well you seemed to be missing the point repeatedly so I though it was only fair to try repeat it until you noticed.

I'm not sure what relevance the slap test has...

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... ...

 

FB-Doug - explain to me the "real world forces on a rudder" that would allow it to impart more force than could be achieved at the max force AOA at a given velocity? The Fmax AOA is the AOA that yields the maximum length vector when the lift and drag components are vector added. How exactly does the rudder exceed that force without more velocity?

 

Since you seem to believe that the amount of force it takes to turn the vessel is irrelevant, why should I bother to explain? So far you seem to think Newton was some kind of hillbilly and that textbook formulae are 100% perfect replications of the real world.

 

In theory, there's no difference between theory and practice. In practice, there is.

 

In your example, the max force would be achieved by fastening the rudder to an immovable object. What if the rudder was attached to an object which suddenly moved the opposite way, hard?

 

Ever steered a boat in waves?

 

FB- Doug

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I thought tautology was the study of the area between the nutsack and asshole that prevents a man from shitting on his nuts. Or is that taintology?

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GOOD LORD

 

my comment was very simple

 

The poster who made the comment I referenced made a tautological statment

Doug disagreed

There is no point disagreeing with a tautological statement so I said so.

 

Feel free to keep explaining why the tautological statement is irrelevant, but I thought I had covered that at the start.

If you think its wrong, you need to go back to the original statement and dissect it a little. :)

 

I think you need to say "tautology" a few more times, cause it'll make you look smarter.

 

I notice you didn't take me up on the 'slap test'.

 

Well you seemed to be missing the point repeatedly so I though it was only fair to try repeat it until you noticed.

I'm not sure what relevance the slap test has...

 

Let me see if I got the point:

 

You're saying that if we take a rudder off the FH, and mount it on a rowboat with force measuring equipment....

Then motor around at 5 or 10 knots and throw the rudder over hard, while measuring the applied forces...

That when the rudder is back on the FH, and it magically hits 10 knots, the rudder will see the exact same force?

 

Sorry, I disagree.... and I'm glad you didn't design *my* boat.

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GOOD LORD

 

my comment was very simple

 

The poster who made the comment I referenced made a tautological statment

Doug disagreed

There is no point disagreeing with a tautological statement so I said so.

 

Feel free to keep explaining why the tautological statement is irrelevant, but I thought I had covered that at the start.

If you think its wrong, you need to go back to the original statement and dissect it a little. :)

 

I think you need to say "tautology" a few more times, cause it'll make you look smarter.

 

I notice you didn't take me up on the 'slap test'.

 

Ahem

This is not a matter of tautology, that would be if the rudder cables broke from being too tight.

 

FB- Doug

is it my turn to say doodie?

 

NO!

 

Say "tautology" 3 times fast, then go get some drywall

 

FB- Doug

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Sa shure get looked down on by woodboats lately. And some of them r here.

I gues im not the nut in the tree. Talk about physico babble bs . wow.

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Indeed. Mind you this rutted discussion makes the motorbike essays look interesting.

What I am enjoying are the number of newbie retards posting about what retards we all are for posting.

Oh yes, this thread has greatness written all over it.

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You fellas keep trying to intuit what ought to be deduced; not unlike how HR engineered his cat.

 

Oh so now Newton's 2nd Law is "intuition"?

What cow college did you study injunearrinck at?

 

You fellas keep mistaking a textbook method for deriving how strong a rudder should be for the real-world forces on the rudder.

 

At the risk of repeating myself- this is why clever engineers often build stuff that breaks...

 

FB- Doug

Ah, back from 3 days of camping to see the ignorance has not abated. Glad to see you guys can keep the fires burning even if I am not around to stoke them.

 

At the risk of repeating myself, the force/work/energy needed to turn the boat is irrelevant, at least to a estimation to three or four significant digits. You just need the maximum V and the area distribution. There is a physics limit on how much force the water flow can impart to the rudder for a given flow velocity. In practice, virtually all boats will, at one time or another, apply that maximum force to the hull regardless of hull mass. This is because the rudder can almost always be turned at a higher angular rate than the boat can be turned (usually by an order of magnitude or so). So long as the rudder structure is appropriate for that force it will not break no matter what it is attached to. If the structure is not appropriate, it will break at some point no matter what it is attached to.

 

FB-Doug - explain to me the "real world forces on a rudder" that would allow it to impart more force than could be achieved at the max force AOA at a given velocity? The Fmax AOA is the AOA that yields the maximum length vector when the lift and drag components are vector added. How exactly does the rudder exceed that force without more velocity?

Camping is gay and your name is still spelt wrong! How can a online discussion about rutters be so farking important to you ,tits?

You need to get out of your tent more.

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GOOD LORD

 

my comment was very simple

 

The poster who made the comment I referenced made a tautological statment

Doug disagreed

There is no point disagreeing with a tautological statement so I said so.

 

Feel free to keep explaining why the tautological statement is irrelevant, but I thought I had covered that at the start.

If you think its wrong, you need to go back to the original statement and dissect it a little. :)

 

I think you need to say "tautology" a few more times, cause it'll make you look smarter.

 

I notice you didn't take me up on the 'slap test'.

 

Well you seemed to be missing the point repeatedly so I though it was only fair to try repeat it until you noticed.

I'm not sure what relevance the slap test has...

 

Let me see if I got the point:

 

You're saying that if we take a rudder off the FH, and mount it on a rowboat with force measuring equipment....

Then motor around at 5 or 10 knots and throw the rudder over hard, while measuring the applied forces...

That when the rudder is back on the FH, and it magically hits 10 knots, the rudder will see the exact same force?

 

Sorry, I disagree.... and I'm glad you didn't design *my* boat.

 

No you did not get the point.

 

the statement is not about throwing the rudder over hard

its about trowing the rudder over with the SAME FORCE.

 

If you mount the rudder on the FH and apply a specified set of forces. (at whatever speed)

 

and then mount the rudder on a rowboat and apply the same set of forces,

 

Guess what

the rudder sees the same set of forces.

 

did you need the dictionary as well as the repetition?

my comment was not about the engineering it was about the poorly worded statement, which said that if we keep two things equal they will be equal.

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Hey Hot Rod,

 

Just wondering if you've done this test on your hull. It is required by the Somalian Coast Guard, so you might want to get it documented now, before you set off around the world:

 

 

 

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"BTW, Catwoman was definitely played by Julie Newmar.

 

Woof !"

 

Yes it probably is Julie. But, Catwoman was also portrayed by;

Lee Meriwether

230px-Catwoman.jpg

 

 

and Eatha Kitt;

 

150px-Eartha_Kitt_Catwoman_Batman_1967.J

I saw all of them as Catwoman, but JN ruled !!

 

The original photo of Batman and Julie Newmar as Catwoman posted here reminds me of THIS !

 

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GOOD LORD

 

my comment was very simple

 

The poster who made the comment I referenced made a tautological statment

Doug disagreed

There is no point disagreeing with a tautological statement so I said so.

 

Feel free to keep explaining why the tautological statement is irrelevant, but I thought I had covered that at the start.

If you think its wrong, you need to go back to the original statement and dissect it a little. :)

 

I think you need to say "tautology" a few more times, cause it'll make you look smarter.

 

I notice you didn't take me up on the 'slap test'.

 

Well you seemed to be missing the point repeatedly so I though it was only fair to try repeat it until you noticed.

I'm not sure what relevance the slap test has...

 

Let me see if I got the point:

 

You're saying that if we take a rudder off the FH, and mount it on a rowboat with force measuring equipment....

Then motor around at 5 or 10 knots and throw the rudder over hard, while measuring the applied forces...

That when the rudder is back on the FH, and it magically hits 10 knots, the rudder will see the exact same force?

 

Sorry, I disagree.... and I'm glad you didn't design *my* boat.

 

No you did not get the point.

 

the statement is not about throwing the rudder over hard

its about trowing the rudder over with the SAME FORCE.

 

If you mount the rudder on the FH and apply a specified set of forces. (at whatever speed)

 

and then mount the rudder on a rowboat and apply the same set of forces,

 

Guess what

the rudder sees the same set of forces.

 

did you need the dictionary as well as the repetition?

my comment was not about the engineering it was about the poorly worded statement, which said that if we keep two things equal they will be equal.

 

You really should stop digging that hole you're in.

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You really should stop digging that hole you're in.

 

If you can explain why its a hole I'm happy to stop digging.

 

K keeps on talking about what happens when you throw the rudder over hard in two different system.... yes in that case there will be different forces on the rudder.

If we apply the SAME forces in each case, then the rudder will move a different amount, but because we are applying the same force (that being the basic assumption made) how do we ever get a different force?

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Hay bag i use a hand held navaid ,it don't show movies.

 

Sorry, it's the Sledgehammer Test.

 

What you do is, you hit the side of your boat as hard as you can with a sledgehammer. If it doesn't make a hole, you pass.

 

And of course, I'm kidding. Lots of pretty capable boats would not take kindly to that treatment.

 

But I do wonder if your planking/layup is a bit thin for the displacement of your boat. Forget the sledgehammer, if you drift against a piling at 2 knots will you be holed?

 

What comparable-size boat did you see that made you choose the 1/2" (3/8"?) plywood with exterior-only glass layup?

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I wonder if the rutter sub-topic will exceed the motorcycle sub-topic in both length and boringness...

too late

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I wonder if the rutter sub-topic will exceed the motorcycle sub-topic in both length and boringness...

 

Seems like it already has. Course no ones seems real impressed with me trying to talk HR out of this suicide he's got planned for himself and his family either. Cat woman might be a pleasant distraction, between AC races. Holly shit what a come back. But Rods hell bent on drowning at sea, I'm just unclear why he wants his family to be right there drowning with him.

 

Oh well.

we now return you to your normally scheduled insanity.

 

PS Rod will never comprehend the rudders discussion anyway, but the diagram of how to attach the outboards, Somebody Else, is just assisting in the guys suicide. Helping him take that death trap much past ankle deep water is criminal IMHO.

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Sa shure get looked down on by woodboats lately. And some of them r here.

I gues im not the nut in the tree. Talk about physico babble bs . wow.

 

So HR I'm kinda curious just why you seem so hell bent on drowning your family to ?

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Ire HD engineering.

 

Picture the FH above the waterline in chrome or diamond plate. The latter may add structural integrity if joints overlap

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I like u better a woodboats.com

u seemed like a upper class

Snaggle tooth ,nob goblin

Instead of your standard here.

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400lbs of ground tackle was not enough ......

 

.550lbs down that better do it.

All part of the fun

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Still wrong...

The skiff will start turning as soon as the rudder is moved off center by a bit so that the peak load will be much lower. The rotational inertia will limit the max force.

Time 0+: rudder is full over, nothing else has moved yet. All three rudders see the same force caused by the relative velocity of the water past the rudder at full deflection.

Yes....I was using a standard physics problem approach of breaking it into steps. In reality, as soon as you move the rudder the boat starts to respond. Simpler for a thought problem if you disassociate those bits into three distinct steps: pre movement, post movement pre response, post movement post response.

 

Results in a step-wise answer to what is really a continuous curve of load vs time, overstates the actual max load, but has the advantage of easier to think through without invoking calculus.

 

Right... resolves acceleration pretty easy... but then you're up against the tautology that if F=MA then obviously M matters but somehow the size of the boat does not!

 

And somebody get to the store, we're out of drywall

 

FB- Doug

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550lbs down

 

So that's the Hardley, two seaguls, your barbie, your mother's wheelchair - will that be enough?

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how much force do you reckon will be pulling on the bow bridle with 500lbs in the mud ? A tad more than a 3 inch drywall screw or two can handle ? Good luck finding a mooring that can handle that amount of windage. If it was my mooring, Id be thinking of my neighbours and the cost of putting the mooring back in its position after you have dragged it across the bay. No moorings available here people, move along, nothing to see here. And Id be keeping my hands in my pockets too. Finger munching causes people to be shy when it comes to shaking your hand or extending you more goodwill. By the sounds of it, you are now plumb out of luck. You might have been better off sitting on the bench with group w....

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Boston go home woodboats is calling.

 

I can see this is going to be a long slow process isn't it Rod ? Was it my asking you to take a long look at your son, and imagine you surviving and him not ? Was it my asking you just how long you think your family might last out there swimming for there lives ? I really am curious why you'd want your family out there with you Rod.

 

Here's a likely scenario, you flounder down the back of a big wave, and a following wave comes over the deck, through the sliding glass door, and swamps your boat. Next wave you hear a groaning sound and one of the hulls begins to drift away. Another wave and its gone. Your in the water no life jacket. Where's your family Rod ? Do you have any plan whatsoever of what to do in this hypothetical situation ? Cause its not so hypothetical. Right about the time you hear Viking screaming for help, the other half, disappears, here comes another wave.

 

My guess is you've been a laborer your whole life, are in reasonably good shape after all that hard work, you'd probably last long enough to watch your family drown, All the psychological defenses in the world won't help you then Rod.

 

Or you could smarten up now, get the boat surveyed, correct if possible all the problems noted in the report, first thing you should do, is get that thing to more sheltered water. Realize the boats not seaworthy. Winds supposed to be really gusting this afternoon and that 35lb anchor you mentioned a while back just doesn't seem like its going to cut it.

 

 

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Just to get this discussion on the right track, here's another shot of Ms. Newmar.

 

Julie-Newmar-Bath-2.jpg

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Wait, I have a Rudder question for HR:

 

Have you been able to successfully control the course of the FH using just the rudders?

 

Seems like that should be one of those things you check first during any sea trials.

 

 

 

Also... I know it was a horrible movie, but I kinda liked this catwoman too:

halle-berry-catwoman-Pictures.jpeg

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Boston go home woodboats is calling.

 

I can see this is going to be a long slow process isn't it Rod ? Was it my asking you to take a long look at your son, and imagine you surviving and him not ? Was it my asking you just how long you think your family might last out there swimming for there lives ? I really am curious why you'd want your family out there with you Rod.

 

Here's a likely scenario, you flounder down the back of a big wave, and a following wave comes over the deck, through the sliding glass door, and swamps your boat. Next wave you hear a groaning sound and one of the hulls begins to drift away. Another wave and its gone. Your in the water no life jacket. Where's your family Rod ? Do you have any plan whatsoever of what to do in this hypothetical situation ? Cause its not so hypothetical. Right about the time you hear Viking screaming for help, the other half, disappears, here comes another wave.

 

My guess is you've been a laborer your whole life, are in reasonably good shape after all that hard work, you'd probably last long enough to watch your family drown, All the psychological defenses in the world won't help you then Rod.

 

Or you could smarten up now, get the boat surveyed, correct if possible all the problems noted in the report, first thing you should do, is get that thing to more sheltered water. Realize the boats not seaworthy. Winds supposed to be really gusting this afternoon and that 35lb anchor you mentioned a while back just doesn't seem like its going to cut it.

 

 

 

It's all part of the fun...

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Anyone following this thread even superficially can not have missed where Hot Rod acknowledged that his initial rudder linkage didn't work as planned. Everyone has seen the make-shift tiller. Everyone should have noted where he's working on a new design for solid linkage steering.

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Anyone following this thread even superficially can not have missed where Hot Rod acknowledged that his initial rudder linkage didn't work as planned. Everyone has seen the make-shift tiller. Everyone should have noted where he's working on a new design for solid linkage steering.

 

Maybe some pics of the new linkage, or a diagram even, would spice things up and help some SA'ers decide the rudder sub-thread isn't so boring after all.

 

Right now we're limping along on drywall jokes and pics of various Catwomen

 

FB- Doug

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Ah, not since the release of the Ford Pinto have I seen a conveyance so ready to offer souls for the taking!

 

Also, I'm amazed that none of you cock-knocking net detectives have realized that meuritt and lilmurray are being played by the same person in this ongoing work of performance art.

 

FB- Dick

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Use your hand to push the stern sideways, to turn your dinghy

Now use your hand to push the stern of a 300m freighter to turn it

 

Which one takes more force?

 

Newton had something to say about these kinda situations

 

Kirwan nailed it (post#7999)

 

FB- Doug

 

 

 

 

Thought experiment - take a board - don't call it a rudder. Stick it in a moving flow- say in a test environment, some sort of water tank. The force on that board will be a function of the flow of the water and the size of the board immersed in that flow. It has nothing to do with the mass it's attached to that holds it in place.

 

That is the max load a board will see. It doesn't matter if it's attached to a dinghy or a supertanker. the max load is a factor of the velocity and area exposed, that's it.

 

Now the duration of that force will be dramatically different depending on what it's attached to. Attached to a super tanker -that max load could continue indefinitely. Attached to a dinghy, you may only see that load for an instant. Design strength needs to take into account the max load + a safety factor. Materials engineering is needed for the duration, cycles, etc.

 

You need to both make sure it's strong enough AND use appropriate materials to handle the duration, cycles, etc.

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Right... resolves acceleration pretty easy... but then you're up against the tautology that if F=MA then obviously M matters but somehow the size of the boat does not!

 

And somebody get to the store, we're out of drywall

 

FB- Doug

 

OK, the attempted re-engage, also known as "thoughts I had while running."

 

I think we are mixing apples and Harlisakis here. F=MA applies in two difference frames of reference.

 

From the rudder's perspective, F=MA describes the maximum force the rudder will feel (or generate). The mass term describes the amount of water impinging on the projected area of the rudder that we are trying to affect, and the accelleration term is how mast are we trying to affect that water. Put slightly differently, that means M is related to the flow rate of water (speed), area of the rudder, and deflection angle (thus projected area). A is related to deflection angle and flow rate - how fast are we trying to push that water out of the way? Note that hull length, overall boat weight, and phase of the moon do not apply here. End result is "total amount of force a given rudder shape can generate at a given speed and deflection."

 

From the boat's perspective, F=MA describes the force required to make the thing move. Now mass describes the weight of the boat (mostly - really needs to include rotational inertia, lateral resistance, location of the pivot point, and some other stuff), and accelleration means how fast are we trying to make the stern move sideways. Force then is the amount required to accomplish that required turn rate. Note that in this frame, overall hull length and weight does matter.

 

Keeping in mind that in general, when you deflect the rudder on a boat, the rudder generates a side force that forces the stern sideways. That sideslip eventually results in changing the vector of the boat's forward motion (or it turns.)

 

So what? If I have a rudder that can survive a 90 degree deflection at 5 knots, it doesn't matter what size hull I strap it to at 5 knots...it won't fail (break.) It may not work worth a damn because it may not generate enough side force to turn a larger hull, but it won't break.

 

 

 

Now, back to the other topic. Is a skim coat appropriate for maritime drywall, or should it be a swirl coat?

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Boston go home woodboats is calling.

 

I can see this is going to be a long slow process isn't it Rod ? Was it my asking you to take a long look at your son, and imagine you surviving and him not ? Was it my asking you just how long you think your family might last out there swimming for there lives ? I really am curious why you'd want your family out there with you Rod.

 

Here's a likely scenario, you flounder down the back of a big wave, and a following wave comes over the deck, through the sliding glass door, and swamps your boat. Next wave you hear a groaning sound and one of the hulls begins to drift away. Another wave and its gone. Your in the water no life jacket. Where's your family Rod ? Do you have any plan whatsoever of what to do in this hypothetical situation ? Cause its not so hypothetical. Right about the time you hear Viking screaming for help, the other half, disappears, here comes another wave.

 

My guess is you've been a laborer your whole life, are in reasonably good shape after all that hard work, you'd probably last long enough to watch your family drown, All the psychological defenses in the world won't help you then Rod.

 

Or you could smarten up now, get the boat surveyed, correct if possible all the problems noted in the report, first thing you should do, is get that thing to more sheltered water. Realize the boats not seaworthy. Winds supposed to be really gusting this afternoon and that 35lb anchor you mentioned a while back just doesn't seem like its going to cut it.

 

 

 

It's all part of the fun...

Last nights little blow was just a small frontal change up nothing much when it comes to what could blow through this time of year. Also HR keep in mind that the length of time between lows cycling through gets shorter the later in the year you wait meaning the move to the Delta might start out with good conditions and end with some pretty nasty stuff before you find your parking spot.

 

As for heading south some of the most amazing conditions I've ever seen were in a race that ended down in Santa Barbara. Winds started out a very mild 20knots outside the GG. By 4am the winds were clocked at spikes over 50knots. We did a spinnaker run basically 100 miles out then gybed the swells were running around 30ft we were doing 19knots boat speed in the troughs and 21 down the fronts. Once down into the SB channel the frequency ie distance between the swells became very short and the top 3-4 feet were breaking off we caught two over the back filling the cockpit to the top. 38hrs of conditions that were pretty brutal though we were in a very very good ocean racing boat and other than shredding a spinnaker we had no concerns of breaking the boat and simply concentrated on driving to avoid getting pooped or tossed on our side. I tell you what getting rolled on your side and having the boat skip down the face of a 30 foot swell at the same time gives you a good pucker facter of 9.

 

I wouldn't even want to do that trip on a well founded cruising CAT or Tri given the wave conditions would have made them really difficult to drive and keep right side up.

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Thought experiment - take a board - don't call it a rudder. Stick it in a moving flow- say in a test environment, some sort of water tank. The force on that board will be a function of the flow of the water and the size of the board immersed in that flow. It has nothing to do with the mass it's attached to that holds it in place.

 

Ok I'll take your though experiment and add this.

 

What exactly do you plan to attach the board to.

 

If you attach it to a piece of polystyrene, and try and turn it relative to the polystyrene (without attaching the polystyrene to the tank walls) what forces do you think you can generate on the board?

Now attach it to the tank wall (a slightly bigger mass). and change the angle wrt to the tank wall.... any differences?

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On any boat of substance - you can load the board. I bet given the same board size, I could load my Multi 23 rudder a shitload more than the Flyin Hawaiian. As I see 20 knots, what will the Hawaiian do, 5? I displace 1000 pounds, his displaces 15000? 20,000? Assuming the same size board, i need a stronger one to deal with max load than the hawaiian.

 

Now - you add in the Hawaiian mass and distinct lack of desire to change direction, and the board size goes up to be effective. Significantly. At some point there's a crossover where the FH will see a max load higher than the multi 23 - not due to speed, but due to size required to be effective to turn the boat.

 

 

Class - in summary: Board strength required is a function of size and max speed, not mass of boat.

 

Board size is what's required to provide enough force to turn the boat. Bigger board, means more strength needed - see above.

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Its just never going to end with the rutters...

 

It's going to end with DEATH.

 

FB- Dick

 

Nonsense, death isn't the end. It's just a shift of narrative.

 

There is a small royalty for using my sign-off. My lawyer will be in touch. Besides, it's too cheerful for you

 

FB- Doug

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Also, I'm amazed that none of you cock-knocking net detectives have realized that meuritt and lilmurray are being played by the same person in this ongoing work of performance art.

 

FB- Dick

 

wow, I'm elevated to performance art!

 

DEAD MAN DINGHY

even though I was skeptical of the initial report from HR, I now have it on good rumor that there was a body recovered. My visitor didn't know any details, so, I will stick my neck out a bit and confirm this report from HR as probably true since it was a topic of conversation along his neck of he waterfront.

 

He also said that for most of yesterday the conditions along Schoonmaker Pt were benign, he first encountered stronger winds when he got up here to central Marin. Maybe RB didn't get the brunt of it, but it was pretty windy here, but just a bit more than what used to be a standard issue summer afternoon

 

Back into hibernation mode until more local color is required, or there is a date set for my next performance.

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Thought experiment - take a board - don't call it a rudder. Stick it in a moving flow- say in a test environment, some sort of water tank. The force on that board will be a function of the flow of the water and the size of the board immersed in that flow. It has nothing to do with the mass it's attached to that holds it in place.

 

Ok I'll take your though experiment and add this.

 

What exactly do you plan to attach the board to.

 

If you attach it to a piece of polystyrene, and try and turn it relative to the polystyrene (without attaching the polystyrene to the tank walls) what forces do you think you can generate on the board?

Now attach it to the tank wall (a slightly bigger mass). and change the angle wrt to the tank wall.... any differences?

Occams Razor is correct.

 

I find it rather bemusing that nobody else seems to understand that the key part of the statement is 'holds it in place'.

 

The only way the maximum forces on the rudder can be any lower than at the max water speed and the ruddr at 90 degrees to the flow is if the mountings for the rudder give way before it can be turned through 90 degrees, OR if the boat it's attached to is smaller than the rudder...

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Its just never going to end with the rutters...

 

I have given up. The rutter discussion has gotten too tedious, even for me, and I am a tedious person.

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Thought experiment - take a board - don't call it a rudder. Stick it in a moving flow- say in a test environment, some sort of water tank. The force on that board will be a function of the flow of the water and the size of the board immersed in that flow. It has nothing to do with the mass it's attached to that holds it in place.

 

Ok I'll take your though experiment and add this.

 

What exactly do you plan to attach the board to.

 

If you attach it to a piece of polystyrene, and try and turn it relative to the polystyrene (without attaching the polystyrene to the tank walls) what forces do you think you can generate on the board?

Now attach it to the tank wall (a slightly bigger mass). and change the angle wrt to the tank wall.... any differences?

Occams Razor is correct.

 

I find it rather bemusing that nobody else seems to understand that the key part of the statement is 'holds it in place'.

 

The only way the maximum forces on the rudder can be any lower than at the max water speed and the ruddr at 90 degrees to the flow is if the mountings for the rudder give way before it can be turned through 90 degrees, OR if the boat it's attached to is smaller than the rudder...

 

How exactly do you manage to hold the rudder in place

I thought the whole point of the rudder was to move the boat.... if the boat is held in place it makes the rudder a bit redundant doesn't it?

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Like u I don't haveto answer anything i don't want to. Aslo I was assaulted buy the master and one of his employees.that's y no charges were filed.But no one on this site figured that out either. And no one wondered why his finger was in my mouth. Two on one is how they play here. This site assumes to much.

 

Actually, I think I did list that possibility :) I hope you keep her afloat and get to hawaii just to piss off many people here.

(Yes, I am one of the people who also said you'd break apart in a 4 foot cross chop)... I still think this situation (when you get moving under sail) will be a true test of your build quality.

 

Hope I am proven wrong. :)

 

PS: consider going to a Junk Rig instead of Marconi, less stress, and easier to handle in many situations (honestly, there is a website about them, and by all reports they have many practical advantages)

http://www.junkrigassociation.org/

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Its just never going to end with the rutters...

 

It's going to end with DEATH.

 

FB- Dick

 

Nonsense, death isn't the end. It's just a shift of narrative.

 

There is a small royalty for using my sign-off. My lawyer will be in touch. Besides, it's too cheerful for you

 

FB- Doug

 

Is the FB for "fine business" ???

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Use your hand to push the stern sideways, to turn your dinghy

Now use your hand to push the stern of a 300m freighter to turn it

 

Which one takes more force?

 

Newton had something to say about these kinda situations

 

Kirwan nailed it (post#7999)

 

FB- Doug

 

 

 

 

Thought experiment - take a board - don't call it a rudder. Stick it in a moving flow- say in a test environment, some sort of water tank. The force on that board will be a function of the flow of the water and the size of the board immersed in that flow. It has nothing to do with the mass it's attached to that holds it in place.

 

That is the max load a board will see. It doesn't matter if it's attached to a dinghy or a supertanker. the max load is a factor of the velocity and area exposed, that's it.

 

Now the duration of that force will be dramatically different depending on what it's attached to. Attached to a super tanker -that max load could continue indefinitely. Attached to a dinghy, you may only see that load for an instant. Design strength needs to take into account the max load + a safety factor. Materials engineering is needed for the duration, cycles, etc.

 

You need to both make sure it's strong enough AND use appropriate materials to handle the duration, cycles, etc.

 

In the engineering business that is called operating in a vacuum. You must be an academic; the rest of us work in the real world.

 

Consider this: What happens to a 300 pound dinghy when you apply 20 pounds lateral force on the stern?

Literally, glue a bathroom scale to your hand, and push as hard on the boat as you can.

It moves. In fact, I'd be surprised if you can generate even that much force, the boat will just keep going away from you.

THIS IS THE MAXIMUM FORCE THAT THE RUDDER ON THAT BOAT CAN SEE. (especially the mounting hardware, which is the likely point of failure)

 

What happens when you push on the stern of the FH with 20 pounds force? I'll bet you can get to 100 pounds lateral force before it moves much.

In order to alter the course of the larger, harder to turn boat, much more force is required. Where is that generated? By the rudder.

THEREFORE, IN THE CASE OF A HEAVIER BOAT, THE RUDDER EXPERIENCES MUCH HIGHER FORCES. QED.

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you're simply wrong. Sorry. By 145 pound International 14 would put huge forces on rudders. I've seen carbon rudder gantries explode. Nothing to do with the mass of the boat - it was all boat speed.

 

Now - if you said for a rudder to be effective for the FH it needs to be 8 times the size of the 14 rudder, and lets say in a 'cane the FH sees 20 knots - then yes, the rudder would see 8 times the force. Find mass in that equation. You won't. Don't take my word for it, plenty of on-line sources on how to calculate the force against a rudder. none mention the size of the boat. Size of the boat only matters when determining how big a rudder you need.

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Its just never going to end with the rutters...

 

It's going to end with DEATH.

 

FB- Dick

 

Nonsense, death isn't the end. It's just a shift of narrative.

 

There is a small royalty for using my sign-off. My lawyer will be in touch. Besides, it's too cheerful for you

 

FB- Doug

 

Is the FB for "fine business" ???

 

In his case: Fragile Balls.

 

FB- Dork

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you're simply wrong. Sorry. By 145 pound International 14 would put huge forces on rudders. I've seen carbon rudder gantries explode. Nothing to do with the mass of the boat - it was all boat speed.

 

Now - if you said for a rudder to be effective for the FH it needs to be 8 times the size of the 14 rudder, and lets say in a 'cane the FH sees 20 knots - then yes, the rudder would see 8 times the force. Find mass in that equation. You won't. Don't take my word for it, plenty of on-line sources on how to calculate the force against a rudder. none mention the size of the boat. Size of the boat only matters when determining how big a rudder you need.

 

If the size of the boat matters in determining the size of the rudder

AND, the size of the rudder affects the forces.

 

how can the size of the boat not affect the forces on the rudder.

 

To put mass into the equation all I have to do is stop assuming the rudder size doesn't change and add in the expression for the required size of the rudder (which you already agree includes the mass)

 

The 'truth' in this whole discussion depends on the assumptions you make.

 

Your underlying assumption is that the boat is hard to turn, and that the problem is quasi-static.

Doug is not assuming a quasi-static case, but instead assumes that the 'light' boat is easy to turn, for a sufficiently easy to turn boat, the maximum focre on the rudder is more limited, hence the 'extreme' polystyrene example, where no matter what you do the force on the rudder is negligible.

The terms you neglect in your equations depend on the scaling terms.

If you want to make the discussion proceed maybe consider at what point the boat mass, or resistance to yaw becomes significant.

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Also, I'm amazed that none of you cock-knocking net detectives have realized that meuritt and lilmurray are being played by the same person in this ongoing work of performance art.

 

FB- Dick

 

wow, I'm elevated to performance art!

 

DEAD MAN DINGHY

even though I was skeptical of the initial report from HR, I now have it on good rumor that there was a body recovered. My visitor didn't know any details, so, I will stick my neck out a bit and confirm this report from HR as probably true since it was a topic of conversation along his neck of he waterfront.

 

He also said that for most of yesterday the conditions along Schoonmaker Pt were benign, he first encountered stronger winds when he got up here to central Marin. Maybe RB didn't get the brunt of it, but it was pretty windy here, but just a bit more than what used to be a standard issue summer afternoon

 

Back into hibernation mode until more local color is required, or there is a date set for my next performance.

 

Ahh, note that meuritt comes back with some weird shit validating HR'FH's rambling. Enough of this performance art! Send the Hawaiian off past the gate!!

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