Announcements
New Discussions
Downhaul under spinnaker
by CapriSun. 11/12/20 09:41 AM
Tornado
by Team_Cat_Fever. 11/02/20 09:45 PM
Previous Thread
Next Thread
Print Thread
Rate Thread
Hop To
Page 1 of 2 1 2
Righting technique #239045
10/15/11 09:47 AM
10/15/11 09:47 AM

M
MarkMT
Unregistered
MarkMT
Unregistered
M



I'm curious about other people's experience in righting their boats singlehanded, particularly the use of the under-tramp righting line like the Falcon has - bungied from the middle of the rear beam and running through blocks at each end of the main beam.

I capsized three times this season and on all occasions needed external help to get the boat up. I'm medium weight, 165-170 lbs and I also use a bag.

In one case the boat was turtled for some 30 minutes (40mph squall - my first 720!) and the mast took a lot of water so I was never going to recover by myself, but the other two times I really should have been able to manage fine.

The reason I'm curious is that on my Blade I had a righting line in the tramp pocket tied to the spin pole and would throw it over the top hull, and I found that worked fine. I'm wondering if the reduction in leverage due to pulling from the inboard side of the hull is what is making the difference. Of course the line is also smaller so a little harder to hang on to.

In hindsight, I can't recall with absolute certainty whether I got the bows into the wind, so it's possible that was a factor, but I'm wondering what other people out there are experiencing.

--Advertisement--
Re: Righting technique [Re: ] #239048
10/15/11 01:22 PM
10/15/11 01:22 PM
Joined: Feb 2005
Posts: 1,382
Essex, UK
Jalani Offline
veteran
Jalani  Offline
veteran

Joined: Feb 2005
Posts: 1,382
Essex, UK
I prefer the line-from-the-mast-base-over-the-upper-hull method. It's never failed me and I've been over (and back up) loads of times - just ask anyone who's been around when I'm racing solo!!!


John Alani
___________
Stealth F16s GBR527 and GBR538
Re: Righting technique [Re: Jalani] #239066
10/17/11 09:02 AM
10/17/11 09:02 AM
Joined: Oct 2002
Posts: 606
Maryland
Kris Hathaway Offline
addict
Kris Hathaway  Offline
addict

Joined: Oct 2002
Posts: 606
Maryland
I used over the hull because most of my racing with the Falcon was single handed and the additional leverage made a difference. Still could right most of the time with Hawaiian setup but it had to be truly into the wind. I also carried a sea anchor just in case I got in conditions where you could not get the bows/mast to face the wind. I raced it between 180-185 most of the time.



Kris Hathaway
Re: Righting technique [Re: Kris Hathaway] #239071
10/17/11 09:57 AM
10/17/11 09:57 AM
Joined: Aug 2005
Posts: 2,921
Michigan
PTP Offline
Carpal Tunnel
PTP  Offline
Carpal Tunnel

Joined: Aug 2005
Posts: 2,921
Michigan
For some reason, I never really thought of the difrerence between the righting line being inboard of the beam vs over the hull. Anybody good enough with math to calculate how much more righting moment you would get from the difference? Seems like an easy physics/ trig question.

Re: Righting technique [Re: PTP] #239073
10/17/11 10:01 AM
10/17/11 10:01 AM
Joined: Jan 2009
Posts: 5,525
pgp Offline
Carpal Tunnel
pgp  Offline
Carpal Tunnel

Joined: Jan 2009
Posts: 5,525
I tried that system and couldn't make it work but bringing it over the hull makes righting a piece of cake.


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: Righting technique [Re: pgp] #239078
10/17/11 10:19 AM
10/17/11 10:19 AM
Joined: May 2003
Posts: 4,451
West coast of Norway
Rolf_Nilsen Offline

Carpal Tunnel
Rolf_Nilsen  Offline

Carpal Tunnel

Joined: May 2003
Posts: 4,451
West coast of Norway
I have not calculated the difference, but..

Consider that the lower hull is the fulcrum you are going to turn the boat over on. By moving the righting line over the hull vs. from the mainbeam you get a real advantage. 50cm is a lot when considering the leverages that is applied.

I think Wouter posted some calculations a long time ago on the min weight needed to right a boat.


I had no issues righting a Tornado solo as long as the wind was sucking (ref Buckminster Fuller). Two up we could right the T without a righting line. Just yanked it up by grabbing the dolphin striker. My partner weighted in at 85kg and myself at 100kg..

Re: Righting technique [Re: Rolf_Nilsen] #239094
10/17/11 12:05 PM
10/17/11 12:05 PM
Joined: Sep 2007
Posts: 571
Hamburg
Smiths_Cat Offline
addict
Smiths_Cat  Offline
addict

Joined: Sep 2007
Posts: 571
Hamburg
If the line is cut to the right length and using the right technic, the righting moment is the same.
However the forces to hold on the line are higher if attached under the tramp, maybe so high that is hard/impossible to hang low enough to get the boat up. Also your fore aft movement is limited and makes it hence more difficult to keep the bows windward. Making some loops in the line, where you want to hook to the trapez helps a lot.
In conclusion if you are not so heavy, the over the hull method is easier to use.
It is also not stupid to have a long line attached to the mast and easy to grab instead a short one under the tramp where you don't get it if you or somebody else need it most.

Cheers,

Klaus

Re: Righting technique [Re: Smiths_Cat] #239098
10/17/11 01:47 PM
10/17/11 01:47 PM
Joined: May 2003
Posts: 4,451
West coast of Norway
Rolf_Nilsen Offline

Carpal Tunnel
Rolf_Nilsen  Offline

Carpal Tunnel

Joined: May 2003
Posts: 4,451
West coast of Norway
Originally Posted by Smiths_Cat
If the line is cut to the right length and using the right technic, the righting moment is the same.


Becouse the weight dont move relative to the rotational axis whichever method is used?

Re: Righting technique [Re: Rolf_Nilsen] #239118
10/17/11 09:05 PM
10/17/11 09:05 PM
Joined: Dec 2005
Posts: 443
Edmonton, Alberta, Canada
bobcat Offline
addict
bobcat  Offline
addict

Joined: Dec 2005
Posts: 443
Edmonton, Alberta, Canada
But the length of the lever does.



F16 Blade 716
Re: Righting technique [Re: bobcat] #239124
10/18/11 09:00 AM
10/18/11 09:00 AM
Joined: Feb 2005
Posts: 4,118
Northfield Mn
Karl_Brogger Offline
Carpal Tunnel
Karl_Brogger  Offline
Carpal Tunnel

Joined: Feb 2005
Posts: 4,118
Northfield Mn
I've heard from a multitude of people that going over the top hull makes all the difference in the world. I know two up it takes nothing to right these boats, but singlehanded and light takes some technique and practice. Calm water, no wind I'm hosed and can not right the boat.

I think this summer I will carry a chunk of line to tie off to the dolphin striker and throw over the top hull just in case.


I'm boatless.
Re: Righting technique [Re: bobcat] #239142
10/18/11 12:00 PM
10/18/11 12:00 PM
Joined: Sep 2007
Posts: 571
Hamburg
Smiths_Cat Offline
addict
Smiths_Cat  Offline
addict

Joined: Sep 2007
Posts: 571
Hamburg
Originally Posted by bobcat
But the length of the lever does.


I don't think so, if you hook on the trapez.

Attached Files
righting.JPG (427 downloads)
Re: Righting technique [Re: Smiths_Cat] #239152
10/18/11 05:45 PM
10/18/11 05:45 PM
Joined: Dec 2005
Posts: 443
Edmonton, Alberta, Canada
bobcat Offline
addict
bobcat  Offline
addict

Joined: Dec 2005
Posts: 443
Edmonton, Alberta, Canada
But it does, doesn't it? By the width of the hull?

Because there would be only small frictional losses as the rope runs over the hull most of your downward force would be at the boats maximum width. I would also suggest that you have moved your rotational force closer to its apex.
What I'm trying to say is that when you go Hawaiian your attachment point has to rise further off the water in order for the mast to come to horizontal. This is while you are pulling down on it. With over-the-hull I imagine it as describing a more lateral movement as the hull works as a pulley.



F16 Blade 716
Re: Righting technique [Re: bobcat] #239153
10/18/11 06:00 PM
10/18/11 06:00 PM
Joined: Dec 2005
Posts: 443
Edmonton, Alberta, Canada
bobcat Offline
addict
bobcat  Offline
addict

Joined: Dec 2005
Posts: 443
Edmonton, Alberta, Canada
My other thought, looking at your diagram is that the Over-the-hull method produces more direct downforce whilst the Hawaiian puts more weight/force onto the soles of your righters feet. Move the righting line to below the dolphin striker. A lot of force on the line and your legs but how much into righting the boat?



F16 Blade 716
Re: Righting technique [Re: bobcat] #239165
10/19/11 11:38 AM
10/19/11 11:38 AM
Joined: Aug 2007
Posts: 118
Pensacola, FL
C
Cab Offline
member
Cab  Offline
member
C

Joined: Aug 2007
Posts: 118
Pensacola, FL
I think Klaus is right. The righting moment stays the same. What changes is the tension/force applied through the righting line. The lower the angle the more tension in the line and the harder it is to pull yourself up as you right the boat.


Chris
Trident F16
Re: Righting technique [Re: bobcat] #239166
10/19/11 11:47 AM
10/19/11 11:47 AM
Joined: Sep 2007
Posts: 571
Hamburg
Smiths_Cat Offline
addict
Smiths_Cat  Offline
addict

Joined: Sep 2007
Posts: 571
Hamburg
Originally Posted by bobcat
But it does, doesn't it? By the width of the hull?

Because there would be only small frictional losses as the rope runs over the hull most of your downward force would be at the boats maximum width. I would also suggest that you have moved your rotational force closer to its apex.
What I'm trying to say is that when you go Hawaiian your attachment point has to rise further off the water in order for the mast to come to horizontal. This is while you are pulling down on it. With over-the-hull I imagine it as describing a more lateral movement as the hull works as a pulley.


No, the only things that matter are the centre of gravity of the boat, the sailor and the centre of buoyancy. All of them are not affect by the attachment of the line.

Quote
My other thought, looking at your diagram is that the Over-the-hull method produces more direct downforce whilst the Hawaiian puts more weight/force onto the soles of your righters feet. Move the righting line to below the dolphin striker. A lot of force on the line and your legs but how much into righting the boat?

Yes, the force in the line increase, up to the point where you simply cant hold anymore. If you can hook to the trapez it is ok, but in some cases the line under the tramp is not long enough to hook to the trapez.

If you are at the lower end of the possible weight range to right the boat, the over the hull method is definetly the way to go.

Re: Righting technique [Re: Smiths_Cat] #239174
10/19/11 06:06 PM
10/19/11 06:06 PM
Joined: Dec 2005
Posts: 443
Edmonton, Alberta, Canada
bobcat Offline
addict
bobcat  Offline
addict

Joined: Dec 2005
Posts: 443
Edmonton, Alberta, Canada
Ok, you have really made my head hurt. But I think I get it. On this teeter totter if the arrows don't move you can move the vertical bars in and out and it will stay in balance. They can get longer or shorter and the balance stays the same.

In the second picture it doesn't matter if the right arrow is sitting on the red bar or suspended from the upper bar. The force doesn't change.

Attached Files
fulcrum.jpg (386 downloads)
capsize.jpg (386 downloads)


F16 Blade 716
Re: Righting technique [Re: Smiths_Cat] #239175
10/19/11 06:14 PM
10/19/11 06:14 PM

M
MarkMT
Unregistered
MarkMT
Unregistered
M



Thanks guys. Good discussion. Smiths Cat's arguments are persuasive.

Re: Righting technique [Re: ] #239197
10/20/11 12:34 PM
10/20/11 12:34 PM
Joined: Jul 2009
Posts: 53
Y
yurdle Offline
journeyman
yurdle  Offline
journeyman
Y

Joined: Jul 2009
Posts: 53
By that logic, there's no difference in leverage on the boat when sailing sitting just inside the hull, and when hiked out in the straps.

Crazy talk.

Re: Righting technique [Re: yurdle] #239198
10/20/11 01:08 PM
10/20/11 01:08 PM
Joined: May 2003
Posts: 4,451
West coast of Norway
Rolf_Nilsen Offline

Carpal Tunnel
Rolf_Nilsen  Offline

Carpal Tunnel

Joined: May 2003
Posts: 4,451
West coast of Norway
Look at the latest drawing Smiths_Cat posted. No matter which line is used, the moments involved does not change.


Re: Righting technique [Re: Rolf_Nilsen] #239206
10/20/11 04:23 PM
10/20/11 04:23 PM
Joined: Nov 2002
Posts: 465
FL
sail7seas Offline
addict
sail7seas  Offline
addict

Joined: Nov 2002
Posts: 465
FL
Perhaps it needs to be reviewed from a dynamics point of view vs a static?
the pivot point of the hull in the water changes/moves in relation to the moment created by the vertical vector downward.
The horizontal vectors work as a couple with it's moment, and not as dynamic.

a bad example: once the sail breaks the water (decreasing resisting moment,
a lot changing here) it usually rights quickly from that point...
So we are really talking about the moment to break the sail free of the water,
but it seems if you bounce up and down (dynamic loads), sometimes the sail can break free of the water.

Page 1 of 2 1 2

Moderated by  Damon Linkous, phill, Rolf_Nilsen 

Search

Who's Online Now
0 registered members (), 26 guests, and 240 spiders.
Key: Admin, Global Mod, Mod
Newest Members
jamieoklahoma, CameronB, stampdk, lwalling, PavelRu
8076 Registered Users
Top Posters(30 Days)
Timbo 1
Forum Statistics
Forums26
Topics22,383
Posts267,009
Members8,076
Most Online1,650
Sep 10th, 2019
Powered by UBB.threads™ PHP Forum Software 7.7.1