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Re: Couldn't right my cat solo. Need advice [Re: Mlcreek] #254388
11/06/12 12:46 PM
11/06/12 12:46 PM
Joined: Jun 2001
Posts: 12,310
South Carolina
Jake Offline
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Originally Posted by Mlcreek
Jake,
As one I-20 skipper to another....would you recommend or not whether to stand on the boards in order to right the I-20. I want to sail solo, but have that concern. I'm 6'2" and 265


I've definitely stood on the tips with no problem (at 175lbs) and would only move out further on the board as needed. Same with my F18. That makes a big difference in the righting leverage you can achieve.



Jake Kohl
-- Have You Seen This? --
Re: Couldn't right my cat solo. Need advice [Re: Andinista] #254389
11/06/12 12:54 PM
11/06/12 12:54 PM
Joined: Aug 2003
Posts: 351
Santiago, Chile
Andinista Offline OP
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Originally Posted by pgp
Have you ever tried it? An under tramp righting system versus an over the hull system? I have and chose the more stable and efficient system as proven by my own experience on the water.

Just out of curiosity, does anyone use an under tramp system? I have never seen one deployed on the water, except my own, and no of no one who uses such a system.

Is it the one on this video? It is stored under the tramp but used over the hulls. About the discussion, I think everybody is right... It is easier to hold your weight with the rope over the hull, but besides making it easier (which matters, per your experience), it doesn't provide more righting moment.

Here's what I'm intending to do: I use a signle line over the hull, like you. But also have a chiken line with a carabiner, that goes inside the rear beam (kept inside with a bungee). I'll just make a loop on the signle line to attach the carabiner and I'll get two points of support. I never liked the idea of having a righting line above the tramp.

Last edited by Andinista; 11/06/12 01:02 PM.
Re: Couldn't right my cat solo. Need advice [Re: Andinista] #254390
11/06/12 01:00 PM
11/06/12 01:00 PM
Joined: Aug 2003
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Santiago, Chile
Andinista Offline OP
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Last edited by Andinista; 11/06/12 01:03 PM.
Re: Couldn't right my cat solo. Need advice [Re: srm] #254393
11/06/12 01:27 PM
11/06/12 01:27 PM
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TeamChums Offline
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Quote
Jake's explanation entirely valid and correct. The position of the rope has absolutely no bearing on whether or not you are able to right the boat, it only affects the forces felt by your body and the reactionary forces on the hull. All that matters is the location of your body's CG in relation to the CG of the boat, the pivot point of the system (lower hull), and any external forces acting on the system (wind & wave forces).



So, by that theory then, in regards to leverage points, a shorter gin pole will be just effective as one that's longer when raising your mast with the trailer winch? Just making a comparison to the dynamics here. Not sure if I agree with Jake's statement (assuming I understood him correctly).


Lee

Keyboard sailors are always faster in all conditions.
Re: Couldn't right my cat solo. Need advice [Re: pgp] #254394
11/06/12 01:30 PM
11/06/12 01:30 PM

M
MN3
Unregistered
MN3
Unregistered
M



diagrams,even ones with boobs

http://www.catsailor.com/forums/ubb...p;Words=boobs&Search=true#Post239275


Originally Posted by pgp
Originally Posted by Jake
Originally Posted by pgp
We get a debate every few months about whether a righting line must come over the top of the hull. Mine does and I have no problem but I'm a lot heavier than you.


There is no debate. From a physics standpoint, it makes no difference whether the line goes over the hull or attaches to the inside of the beams. Over the hull may make the line a little easier to hold yourself on to with your hands - but it doesn't give you any additional leverage to right the boat. None, zip, zero. You weigh what you weigh, the boat weighs what it weighs. As long as neither one of you is moving in relation to the other (i.e., you are dangling off the end of the righting line), the position or angle of that line makes absolutely no difference on righting the boat because you are connected to the boat at all points (your feet and your hands) effectively making a closed system. Any angle change that you make with the line affects the amount of pressure your feet exert on the hulls and they cancel each other out. It's only about getting your weight out further from the CG of the boat to cause the CG of you+boat to move out beyond the pivot point so it will start to rotate up.


Speak for yourself. There's more to the problem than physics, like balance, but I'm not even sure your analysis is valid.

In any case, I returned the under tramp system to the supplier and have used a simple rope over the hull ever since.

Re: Couldn't right my cat solo. Need advice [Re: Andinista] #254395
11/06/12 01:34 PM
11/06/12 01:34 PM
Joined: Aug 2003
Posts: 351
Santiago, Chile
Andinista Offline OP
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The winch is external to your rotating system (mast), that would be like righting the cat from a motorboat, not standing on the hull.

Re: Couldn't right my cat solo. Need advice [Re: Andinista] #254396
11/06/12 01:43 PM
11/06/12 01:43 PM
Joined: Aug 2003
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Santiago, Chile
Andinista Offline OP
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The boobs diagram was wrong.. (except for the boobs)
The right one:
[Linked Image]

Re: Couldn't right my cat solo. Need advice [Re: Andinista] #254397
11/06/12 01:53 PM
11/06/12 01:53 PM
Joined: Jul 2004
Posts: 125
Clinton, Mississippi
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It appears there are differences of opinion here about what "leverage" means. Jake and srm are correct about the physics....the righting line position doesn't affect the righting moment. However, putting the line over the hull gives an angle that requires less force (strength) for one to hold his body weight up just above the water...and it makes balancing easier. This could be considered leverage as well, I suppose. Therefore, if it works and is easier under the hull, do that. Otherwise, fling it over.

I agree with Karl on the ditching mast float if possible. If the mast is sealed and you can tolerate the occasional turtle, get rid of the extra weight at the end of that long moment arm.

A few strategically placed knots in the righting line can be very beneficial...a couple for hand-holds/climbing and one placed where your butt is just above the water when you hook the righting line in your harness and lean out. The harness carries the load instead of your arms. Then you can fling your arms back like a rodeo cowboy (for additional moment) or use them to properly deploy the righting bag. The bag should be on a separate righting line, as far out as possible (over your shoulder), and just above the water as well. The problem is that, as the mast comes up, you and the bag go in the water and your bouancy neutralizes the righting force, so you (and the bag) have to get up higher. You have to climb your righting line some, and a 3:1 purchase with camcleat on the righting bag line is invaluable.

For reference, I'm short (~5'7"), weigh ~ 175 lbs., and can right my Hobie 16 using the large Murray's bag without the wind helping. I've righted it without the bag a few times in 15 mph+, but wouldn't come close without significant wind assistance.


Jerome Vaughan
Hobie 16
Clinton, Mississippi
Re: Couldn't right my cat solo. Need advice [Re: Andinista] #254398
11/06/12 02:01 PM
11/06/12 02:01 PM
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pgp Offline
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No. Everyone I know keeps a line attached to the dolphin striker and stored in a bag on the tramp. When you go ever you must first do all that house keeping, then throw the line over the hull, get yourself situated securely, then fill a couple of black plastic garbage bags (one stuffed inside the other, they're kept in the bag with the line) with water and lift them into your lap. You will probably have to experiment with the right rope length but that should do it. If it doesn't I'd next try taking the mast float off, as Karl suggested.


Pete Pollard
Blade 702

'When you have a lot of things to do, it's best to get your nap out of the way first.

Re: Couldn't right my cat solo. Need advice [Re: pgp] #254404
11/06/12 02:54 PM
11/06/12 02:54 PM

M
MN3
Unregistered
MN3
Unregistered
M



Originally Posted by pgp
No. Everyone I know keeps a line attached to the dolphin striker ...... then fill a couple of black plastic garbage bags with water and lift them into your lap


I don't tie anything to my striker.

a plastic bag filled with water (or2) would never right my 5.5. I need 2 adults or 1 adult and a large murray's righting bag, and even then its a struggle)

Re: Couldn't right my cat solo. Need advice [Re: TeamChums] #254408
11/06/12 04:03 PM
11/06/12 04:03 PM
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Posts: 12,310
South Carolina
Jake Offline
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Originally Posted by TeamChums
Quote
Jake's explanation entirely valid and correct. The position of the rope has absolutely no bearing on whether or not you are able to right the boat, it only affects the forces felt by your body and the reactionary forces on the hull. All that matters is the location of your body's CG in relation to the CG of the boat, the pivot point of the system (lower hull), and any external forces acting on the system (wind & wave forces).



So, by that theory then, in regards to leverage points, a shorter gin pole will be just effective as one that's longer when raising your mast with the trailer winch? Just making a comparison to the dynamics here. Not sure if I agree with Jake's statement (assuming I understood him correctly).


The longer ginpole reduces the amount of load on the line much in the same way that having the righting line over the hull reduces the load you have to hold with your hands...but it doesn't change the total amount of force the mast needs to reach vertical or that the boat needs to be righted. Look at the two diagrams in the image below. The differences in the rope angle will not have any affect on the physics in the situation to help you right the boat. The rope in the top diagram will be easier to hang on to - but won't make the boat come up any faster.

[Linked Image]




Attached Files
rightingdiagram.jpg (279 downloads)

Jake Kohl
Re: Couldn't right my cat solo. Need advice [Re: Jake] #254409
11/06/12 04:32 PM
11/06/12 04:32 PM
Joined: Aug 2003
Posts: 351
Santiago, Chile
Andinista Offline OP
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Originally Posted by Jake
[quote=TeamChums]
The longer ginpole reduces the amount of load on the line much in the same way that having the righting line over the hull reduces the load you have to hold with your hands...but it doesn't change the total amount of force the mast needs to reach vertical or that the boat needs to be righted.


This discussion is so useless.. but anyway..
In this case there is a difference. The maximum tension you can produce with the winch will be the same independently of the length of the ginpole. Therefore the torque that can be applied to the mast may change with the length of the ginpole. It's not the same case as the person hanging on the rope, becaue the winch is not rotating with the mast, it's external to the rotating system. The person, on the other hand, has nothing external to the rotating system to grab and increase any force. His weight is fixed so the only thing he can do is move it around.

But the winch won't help on board.. unless you tie it to the mast float, swim away with it and turn the handle REALLY fast...
Maybe use the righting bag as a sea anchor..

Last edited by Andinista; 11/06/12 04:50 PM.
Re: Couldn't right my cat solo. Need advice [Re: Andinista] #254410
11/06/12 04:37 PM
11/06/12 04:37 PM
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Santiago, Chile
Andinista Offline OP
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Or have one for each shroud and change the mast angle.....

Re: Couldn't right my cat solo. Need advice [Re: Andinista] #254412
11/06/12 05:35 PM
11/06/12 05:35 PM
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Kingston SE South Australia
JeffS Offline
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I have used righting poles and ropes here are definate facts
I made my first righting pole too short and it didn't work, I made a longer one and it worked. Its just a lever it has to work the only limitation is how far you get from the pivot point. Further out the more leveredge.
I have used righting ropes on many cats, the under tramp system is neat and great when it works but if you can't get your cat back up throw the rope over the hulls like I did and you will never go back to an under tramp system. The reason over hull system works is you are adding more height to your leveredge by pulling the object from higher thereby increasing the leveredge on the object. When you pull a tree over you don't tie your rope around the middle you tie it around the top


Jeff Southall
Current boats
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Re: Couldn't right my cat solo. Need advice [Re: JeffS] #254414
11/06/12 08:09 PM
11/06/12 08:09 PM
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Santiago, Chile
Andinista Offline OP
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Because you are standing on the ground. If you were standing on the tree it wouldn't make much difference, other than tension the rope more or less.

I just got a nice windsurf mast for 20 bucks. I'll test it to figure out the right length and then cut it. Thanks everybody.

Re: Couldn't right my cat solo. Need advice [Re: JeffS] #254424
11/07/12 07:37 AM
11/07/12 07:37 AM
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South Carolina
Jake Offline
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Originally Posted by JeffS
I have used righting poles and ropes here are definate facts
I made my first righting pole too short and it didn't work, I made a longer one and it worked. Its just a lever it has to work the only limitation is how far you get from the pivot point. Further out the more leveredge.
I have used righting ropes on many cats, the under tramp system is neat and great when it works but if you can't get your cat back up throw the rope over the hulls like I did and you will never go back to an under tramp system. The reason over hull system works is you are adding more height to your leveredge by pulling the object from higher thereby increasing the leveredge on the object. When you pull a tree over you don't tie your rope around the middle you tie it around the top


I understand how clingy this idea is but it's just not true. I have a degree in this. It makes it easier to hold on to the rope but will not give you more mechanical advantage to right the boat because you and the boat are essentially a "closed system". You are attached to the boat at every point - your feet, your arms, the rope. The only thing that affects the physics of righting the boat is how far you extend your weight from the center of rotation (the hull in the water). You move your weight out to move the center of gravity for the system (you, the boat, the lift of the sails) past the pivot point to the underside of the boat so it will start to rotate and right itself.


Jake Kohl
Re: Couldn't right my cat solo. Need advice [Re: Andinista] #254425
11/07/12 08:58 AM
11/07/12 08:58 AM
Joined: Feb 2007
Posts: 61
Albenarle NC
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jackbr549 Offline
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Albenarle NC
Leave it as is, the world seems up-side-down today anyway!

Re: Couldn't right my cat solo. Need advice [Re: Andinista] #254431
11/07/12 11:54 AM
11/07/12 11:54 AM
Joined: Jun 2009
Posts: 524
Petten Netherlands
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northsea junkie Offline
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Petten Netherlands
I totally agree with that, Jake.
And getting your weight more outboard can only be done with a pole.

A simple but strong enough pole with on one end a forkisch like end-piece which you put and let rest in the corner of the forebeam and the down-hull will do (the other pole end is attached to the uphaul line which comes from above.

Now a very simple method of testing this and determing the appropriate lenght of the pole (and the length of the uphaulline) is "dry-swimming".
Pull your cat, fully rigged, on a beach on its side. Mount your pole and try to lift everything back. Imitate if your on the water.

Bare in mind that an actual capsized position in the water is less difficult (or at least the same) then what you have just tried. Because in the water the down-hull is deeper in the water then on the sand. (Assuming that the masttop in the watersituation is just level with the surface, so use a ball!)

ronald reeder


ronald
RAIDER-15 (homebuilt)

hey boy, what did you do over there, alone far out at sea?..
"huh....., that's the only place where I'm happy, sir.
Re: Couldn't right my cat solo. Need advice [Re: northsea junkie] #254439
11/07/12 04:01 PM
11/07/12 04:01 PM
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Gulf Coast relocated from Cali...
TeamChums Offline
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Wish I had a link to show the photos of Hobie Gary's system "The Solo Right". He mad a "lever" (usually out of an oar) that had a small plastic "wafer" on the paddle end that would keep the end in the dagger board pocket. Then there were two lines, one that attached to each crossbar at the hull intersection. The lever/oar was made to angle up slightly out over the water by the length of each line. Then you took your regular righting line out with you as you stepped back out on the lever/oar. As the boat came up, you went hand over hand up the righting line and the boat righted.
He made the same type of system for my H21se out of a H16 boom with some non skid tape on it. It worked perfect. I was able to right that boat solo with that system.


Lee

Keyboard sailors are always faster in all conditions.
Try cantelever shroud adjusters, [Re: TeamChums] #254441
11/07/12 05:12 PM
11/07/12 05:12 PM
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jpayers Offline
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Hey Guys,
I changed my shroud adjusters to the cantalever kind. I capsized on myself hiked out on the trapeze. Instead of pulling on the righting bar I made the difficult climb to the high shroud adjuster to pull the pin. The net effect on the center gravity was radicaly changed by extending the shroud out 5 inches. I don't think it will self right but it helps.

Holdyourcourse,
J.P.Ayers
Isotope 186

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