I'm replacing my standing rigging (thanks Gene) and wanted to know what the recommend shroud tension is? Whats are the different light-med-heavy wind ranges and tension settings.
Thanks
Scott
Shroud Tension
Re: Shroud Tension
Good Question! I could use the same info.
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San Juan Sailboats
- Posts:50
- Joined:Fri Mar 25, 2011 10:36 pm
- Location:Seattle WA
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Re: Shroud Tension
Rigging tension has not proven to be a critical factor on our boats.
When you look at all the boats at a national event, the shroud tensions are all over the place. The fastest boat I know of (a certain green frog ) has theirs very loose, another boat owned by a sail-maker has theirs rather snug.
The only numbers I have found are from Interbank sails. 29 on the inners, 21 on the outers.
I think the main consideration is to have the inners tighter than the outers so the mast center section does not bend forward when you crank on the back stay. This can cause nasty looking wrinkles in the main.
When you look at all the boats at a national event, the shroud tensions are all over the place. The fastest boat I know of (a certain green frog ) has theirs very loose, another boat owned by a sail-maker has theirs rather snug.
The only numbers I have found are from Interbank sails. 29 on the inners, 21 on the outers.
I think the main consideration is to have the inners tighter than the outers so the mast center section does not bend forward when you crank on the back stay. This can cause nasty looking wrinkles in the main.
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Missleedee
- Posts:6
- Joined:Sun Aug 07, 2011 3:20 am
Re: Shroud Tension
New here so I've been reading everything. Is this info old about tuning (shroud tension) http://members.shaw.ca/SJFleet28/ . You may have to click on the tuning ideas link to get there. I'm sure a lot of it depends on the cut of a sail (Sails) and requires adjusting underway to get the perfect sail shape for wind force.
Lee and Rick
Lee and Rick
Re: Shroud Tension
I hafta say, North Sails' advice to retain the genoa to 23 or more knots TWS is ... unexpected. 
Few SJ21 sailors use the genoa anyhow because the boat is so easily driven to hull speed under working sails, and because of its natural lee helm. I cannot IMAGINE going to weather in 23 knots with a 150% genoa on this boat. It is not a design that likes to be horsewhipped upwind. Do all North Sails employees own J/24s, or what? 
At 15-18 true, I'm reefing the main; anything over 25, the working jib gets furled or goes away. Boat thrashes less, & I've watched speeds increase when sail is shortened.
For us the crossovers are:
0-10 kts true (up to 5.4 kts boat speed): full main & 150% nylon drifter.
11-18 kts true (up to 6.5 kts boat speed): full main & working jib.
19-25 kts true (until lee rail is in water or boat starts broaching on reaches): reefed main and full working jib.
26-30 kts true: reefed main and partial jib.
31 kts and up: reefed main only.
When the boat seems to be struggling, we've found reducing sail one notch flattens it out & usually adds a half knot or so of boat speed. YMMV. We don't hike the SJ21 or drive it as brutally as some racers might, and our mountain winds are gustier than most coastal areas, so we need to set the boat up for peak winds rather than average.
Few SJ21 sailors use the genoa anyhow because the boat is so easily driven to hull speed under working sails, and because of its natural lee helm. I cannot IMAGINE going to weather in 23 knots with a 150% genoa on this boat. It is not a design that likes to be horsewhipped upwind. Do all North Sails employees own J/24s, or what? At 15-18 true, I'm reefing the main; anything over 25, the working jib gets furled or goes away. Boat thrashes less, & I've watched speeds increase when sail is shortened.For us the crossovers are:
0-10 kts true (up to 5.4 kts boat speed): full main & 150% nylon drifter.
11-18 kts true (up to 6.5 kts boat speed): full main & working jib.
19-25 kts true (until lee rail is in water or boat starts broaching on reaches): reefed main and full working jib.
26-30 kts true: reefed main and partial jib.
31 kts and up: reefed main only.
When the boat seems to be struggling, we've found reducing sail one notch flattens it out & usually adds a half knot or so of boat speed. YMMV. We don't hike the SJ21 or drive it as brutally as some racers might, and our mountain winds are gustier than most coastal areas, so we need to set the boat up for peak winds rather than average.
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Black Jack
- Posts:21
- Joined:Wed Jun 22, 2011 3:07 am
Re: Shroud Tension
I think overall most of our fleet overall does little with rig tune and set up. At least from what I have seen here on on the east coast.
I can tell you I have been very successful with tuning my rig for the conditions. I set my rig up specifically for each day I go out sailing.
First I choose the headstay length I want for the wind conditions. I play the headstay between about 6 inches from light to heavy air. This is extreme and I think most are very successful with very little change to this as
Iong as they have chosen a mid setting. I will say if you are sailing at either end of the wind range in a mid setting against a good boat who is specifically set for either extreme you will be at a disadvantage.
After getting the headstay were I want it, I set the shroud tension to follow. For me shroud tension plays a huge part when it comes to back stat tension and head stay sag. Also evaluating how the mast stays in column when sailing helps to understand how best to tune the rig. I have a developed my own rig tuning guide that has worked well for my personal style of sailing. I continue to update and change it as I learn more about the boat.
Overall I think most people will be very successful by sailing a base setting all season and this is proven all the time. But when you see one particular boat be very fast in light or heavy air, it may not be just the helmsman, but also the setup. I know when I have my light air or heavy air set ups I am very fast against those who never change their setup. For me there is a huge change in my set up between the very light and heavy wind sailing.
My point with this is to get out and experiment with different set ups and see how it works for you. I have tested the extremes in our Wednesday night races and can tell you there is a big difference in performance when your boat is set up for the conditions.
Good luck and work to your own conclusions and do not be complacent with the opinion that these boats do not respond to fine tuning your equipment for the conditions, then share and let us all learn from each others experiences.
Dan Bornarth
Black Jack #2403
I can tell you I have been very successful with tuning my rig for the conditions. I set my rig up specifically for each day I go out sailing.
First I choose the headstay length I want for the wind conditions. I play the headstay between about 6 inches from light to heavy air. This is extreme and I think most are very successful with very little change to this as
Iong as they have chosen a mid setting. I will say if you are sailing at either end of the wind range in a mid setting against a good boat who is specifically set for either extreme you will be at a disadvantage.
After getting the headstay were I want it, I set the shroud tension to follow. For me shroud tension plays a huge part when it comes to back stat tension and head stay sag. Also evaluating how the mast stays in column when sailing helps to understand how best to tune the rig. I have a developed my own rig tuning guide that has worked well for my personal style of sailing. I continue to update and change it as I learn more about the boat.
Overall I think most people will be very successful by sailing a base setting all season and this is proven all the time. But when you see one particular boat be very fast in light or heavy air, it may not be just the helmsman, but also the setup. I know when I have my light air or heavy air set ups I am very fast against those who never change their setup. For me there is a huge change in my set up between the very light and heavy wind sailing.
My point with this is to get out and experiment with different set ups and see how it works for you. I have tested the extremes in our Wednesday night races and can tell you there is a big difference in performance when your boat is set up for the conditions.
Good luck and work to your own conclusions and do not be complacent with the opinion that these boats do not respond to fine tuning your equipment for the conditions, then share and let us all learn from each others experiences.
Dan Bornarth
Black Jack #2403
Re: Shroud Tension
I don't spend a lot of time with shroud tension, I just don't want to mess with it, but my general rule is that the inners should feel medium to light and the outers slightly less than that. I don't think this is the ideal tension for speed, but I try and keep them pretty loose as much as I can for the life of the boat. The reality is that if you crank up the shrouds to the tensions recommended in the North tuning guide, you will deform your boat over time. These boats are just too old and too underbuilt to hold up against much shroud tension for very long. If I'm trying to sail in a serious regatta I'll tighten them down, but I try not to leave them tight for very long.
Bob Abelin - National Commodore
#714 Blue Pearl MK 1
#714 Blue Pearl MK 1
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Black Jack
- Posts:21
- Joined:Wed Jun 22, 2011 3:07 am
Re: Shroud Tension
Bob,
I agree, I do not keep a lot of tension on the rig as I do not think it is good for these old boats. I turn up the tension on those particular days that I need it, then release the tension soon after. for the most part I work on the lighter side of the tension and it is better to error on the lighter side than the tighter side except in windy conditions.
I think one of the greatest benefits is easing the rig in light air conditions. You almost can not get it loose enough for real light conditions.
The whole conversation just goes to show everyone that overall rig tension probably does not play a huge role in being successful in the San Juan 21 as there is a huge variation between those who tune for the conditions and those who just sail with what they have. There are some other components to the race that are critical to the success. This woud be true here in NC as well. I just can not help myself and tuning the rig is just part of my enjoyment in competing in sailing events. Been racing one-design boats for over thirty years and have always tuned my boats for the conditions I raced. Hard to change that philosophy now.
Dan Bornarth
Black Jack
# 2403
I agree, I do not keep a lot of tension on the rig as I do not think it is good for these old boats. I turn up the tension on those particular days that I need it, then release the tension soon after. for the most part I work on the lighter side of the tension and it is better to error on the lighter side than the tighter side except in windy conditions.
I think one of the greatest benefits is easing the rig in light air conditions. You almost can not get it loose enough for real light conditions.
The whole conversation just goes to show everyone that overall rig tension probably does not play a huge role in being successful in the San Juan 21 as there is a huge variation between those who tune for the conditions and those who just sail with what they have. There are some other components to the race that are critical to the success. This woud be true here in NC as well. I just can not help myself and tuning the rig is just part of my enjoyment in competing in sailing events. Been racing one-design boats for over thirty years and have always tuned my boats for the conditions I raced. Hard to change that philosophy now.
Dan Bornarth
Black Jack
# 2403
Re: Shroud Tension
Dan,
Any hints on what the gauge settings would be for different wind ranges? I'm the lone SJ down in S. Florida so I don't have any boats to tune against.
Any hints on what the gauge settings would be for different wind ranges? I'm the lone SJ down in S. Florida so I don't have any boats to tune against.
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Black Jack
- Posts:21
- Joined:Wed Jun 22, 2011 3:07 am
Re: Shroud Tension
I have a guide I use for tuning the San Juan 21. It is continually evolving and should only be considered a guide. But I have been successful with these number.
wind speed Headstay length Upper shroud Lower shroud
0 to 5 knts Approx 24' 7" 10 - 15 15 - 20
6 - 10 Approx 24' 5 " 15 - 20 20 - 25
11 - 15 Approx 24' 4" 20 - 25 26 - 32
16 - 20 Approx 24' 2 25 30 - 35
21 plus Approx 24' 1 30 35
Again this is only a guide using the Loose guage. I have played one end of the range or another based on sea condition and number of crew. Sailing with three big guys would make a difference from sailing with me and my two young children or sailing with two crew.
I hope others will offer their rig settings so we could all learn from each other. Nothing is set in stone and I try new settings all the time in an effort to learn and I add it to my tuning guide.
Dan Bornarth
Black Jack
#2403
wind speed Headstay length Upper shroud Lower shroud
0 to 5 knts Approx 24' 7" 10 - 15 15 - 20
6 - 10 Approx 24' 5 " 15 - 20 20 - 25
11 - 15 Approx 24' 4" 20 - 25 26 - 32
16 - 20 Approx 24' 2 25 30 - 35
21 plus Approx 24' 1 30 35
Again this is only a guide using the Loose guage. I have played one end of the range or another based on sea condition and number of crew. Sailing with three big guys would make a difference from sailing with me and my two young children or sailing with two crew.
I hope others will offer their rig settings so we could all learn from each other. Nothing is set in stone and I try new settings all the time in an effort to learn and I add it to my tuning guide.
Dan Bornarth
Black Jack
#2403