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

Timmys_Trick_Turkey

Super Anarchist
1,604
2
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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Boston1

Super Anarchist
3,653
0
BF colorado
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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Remodel

Super Anarchist
10,329
925
None
Just to get this discussion on the right track, here's another shot of Ms. Newmar.

Julie-Newmar-Bath-2.jpg


 
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:



 
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βhyde

Super Anarchist
8,358
1,958
Beside Myself
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...

 

Somebody Else

a person of little consequence
7,698
858
PNW
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.

 

Steam Flyer

Sophisticated Yet Humble
45,530
10,251
Eastern NC
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

 

Reaper: Grim

New member
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

 

Raz'r

Super Anarchist
63,128
5,850
De Nile
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.

 
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?

 

U20guy2

Super Anarchist
12,330
3
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.

 

JohnMB

Super Anarchist
2,853
620
Evanston
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?

 

Raz'r

Super Anarchist
63,128
5,850
De Nile
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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