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 Post subject: trap line for righting?
PostPosted: Sat Jul 10, 2010 4:26 pm 
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I had a thought: Is it possible to use a trap wire for righting the 16? Would you gain more leverage? I have my trap wires routed and free floating under the tramp with shock chord so it would be easy to snap a line to it and bring it to the front of the tramp. Go ahead an laugh if the idea is ridiculous. Just wondering.... :roll:

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PostPosted: Sun Jul 11, 2010 7:25 am 
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I don't think it's ridiculous at all, in fact I've posted the same question. It makes sense because ultimately you'd be pulling directly on the mast itself which is the whole point in righting.

I have both a righting line circumnavigating the pylons and a righting bucket for when I solo because when I first got my boat I thought that's what you did. Both pull on the mast indirectly either by way of the pylons or the dolphin striker; Why not just pull on the mast itself by way of the trap line? Makes sense to me and I think you'd have more leverage.

I haven't spent time resolving the connection method, but it would seem like it would only be a matter of connecting a line to one of the handles or dog bone which, admittedly, wouldn't be easy getting above the airborne hull while she's over. I'd probably rather pull between the hull topsides and underside of the tramp because I don't like the idea of all that pressure from one line on the hull. Maybe a 2" wide trailering strap could work....

The next time I'm at my boat I'm going to check the geometry of it all because like you I really think it's a better way to go and am surprised it hasn't been pursued yet unless I'm missing something really obvious.

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PostPosted: Mon Jul 12, 2010 3:25 am 
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I had thought of a quick release method to get a line on the trap wire but hadn't thought of how I'd get to it because of the height. Good point. The only thing I am thinking of is to leave a long rope hanging from it. But, I don't think I cold deal with another line fouling up everything when I'm getting on and off the wire. hmm....

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PostPosted: Mon Jul 12, 2010 11:14 am 
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There's already a direct connection between the mast and the upper hull - the shroud - so pulling on the trap wire will not give you any additional leverage.

The best righting "system" is still just a length of easy to grip line, tied to the dolphin striker and stored in a tramp bag or pocket.

Pull it out, flip it over the top hull and hang low on it until the boat comes up. Sometimes, I'll take a turn around my trap hook to help hold me in place.


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PostPosted: Mon Jul 12, 2010 12:25 pm 
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I use a slightly different way to hold the righting line. I tie one end to one pylon and take it around the dolphin striker, then tie the other end to the other pylon. When the boat is on its side, I untie the line from the lower pylon and throw the end over the "up" hull. No need to store the line in anything.

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PostPosted: Mon Jul 12, 2010 3:12 pm 
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hrtsailor wrote:
I use a slightly different way to hold the righting line. I tie one end to one pylon and take it around the dolphin striker, then tie the other end to the other pylon. When the boat is on its side, I untie the line from the lower pylon and throw the end over the "up" hull. No need to store the line in anything.

Unless you loop it around something while it's stowed, it's not long enough to meet the class rule minimum length of 14':
Quote:
8.2 A minimum* 3/8 in. (9.53 mm) diameter righting
line or webbing consisting of at least one 14 ft.
(4.27 meter) length of line or webbing, or two 8
ft. (2.44 meter) lengths of line or webbing shall
be securely attached and readily accessible
from each side of the boat. The righting lines or
webbing shall be in addition to all other required
equipment. (Unless specified differently in individual
boat class rules)


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PostPosted: Thu Jul 15, 2010 5:41 am 
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The shroud, of course, should have thought of that.

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PostPosted: Fri Jul 16, 2010 11:23 am 
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The forces at play when righting a Hobie are the same forces involved when playing on a "teeter-totter" at a playground The lower hull acts as the fulcrum. The leverage of the crew weight + the lift generated by the sails must overcome the leverage generated by the weight of the rig. When this happens, the boat comes up.

To benefit from the lift generated by the sails, the boat must be pointed as close to head-to-wind as possible. This gets airflow across the sail generating upward lift. In order to increase the leverage of the crew, the only options are to move the crew farther outboard (via a righting pole) or increase the crew weight (via righting bag or eating more pizza).

Tieing your righting line to a trap line will not increase the crew's leverage in any way. What you're describing is the equvalent of trying to lift yourself off the ground by reaching down and pulling up on your feet - it won't do anything accept make your arms tired.

sm


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PostPosted: Tue Jul 27, 2010 9:20 pm 
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Good physics problem. SRM you are right. Pulling on the trap line decreases the rotational force needed to right the hobie. I have read on here it takes somewhere around 285 lbs to right a hobie. With the line thrown over a pontoon and tied off at the dauphin striker you are maximizing the upward/rotational force. Pulling on the mast tang via the trap wire decreases the upward/rotational force. Estimating the distance from the outside of the bow to the center line of the boat as 4 feet, and estimating the mast tang to be 18 feet up I would reckon you would need about 1200 pounds to right it pulling on the trap wire. Doesn't sound right but that is what my trigonometry is saying. Anyone want to do some field tests?

Branson

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PostPosted: Wed Jul 28, 2010 4:55 am 
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branson wrote:
Good physics problem. SRM you are right. Pulling on the trap line decreases the rotational force needed to right the hobie. I have read on here it takes somewhere around 285 lbs to right a hobie. With the line thrown over a pontoon and tied off at the dauphin striker you are maximizing the upward/rotational force. Pulling on the mast tang via the trap wire decreases the upward/rotational force. Estimating the distance from the outside of the bow to the center line of the boat as 4 feet, and estimating the mast tang to be 18 feet up I would reckon you would need about 1200 pounds to right it pulling on the trap wire. Doesn't sound right but that is what my trigonometry is saying. Anyone want to do some field tests?

Branson


I never thought math would be so handy when righting a hobie!LOL Great stuff! ps, I really suck at math... :?

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PostPosted: Thu Jul 29, 2010 1:50 pm 
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Hey thanks branson, great explanation!

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