Square Top main
#1
Posted 15 June 2012 - 01:25 AM
Up to now, I've added a sliding bowsprit and an asymmetrical spinnaker, and have modified the original rig by sweeping back and lengthening the spreaders and moving the shrouds outboard and back, eliminating the backstay.
I'm using a 100% blade jib and a fully battened VERY roachy main. the boat sails really well in a breeze and the modified rig seems very stable. The boat is a lot more fun to sail now than it was with the 155% genny since in a breeze the main works well without the 155 backwinding it.
Problem is, in light air, i'm missing the sail area I gave up by going from the 155 to the 100% jib. The larger main helps, but I want to add more area and have the mainsheet, vang and traveller capacity to ( I believe ) manage a square top main. I can accommodate a 24'6" luff and a 9'9" foot. I understand the center of effort / center of lateral resistance concept and can tweak mast position and rake accordingly. Right now the boat is well balanced with it's sail of those dimensions and lots of roach.
I know it's probably more practical to buy a different boat etc. etc. but playing around with this boat is fun and as much a hobby as a quest.
Can anyone suggest a good source for an appropriate mainsail? Looking for outside the box ideas as opposed to "Contact North Sails"
Thanks for any constructive ideas!
Paul
St. Augustine
#2
Posted 15 June 2012 - 01:41 AM
#3
Posted 15 June 2012 - 06:24 AM
Got any Pics of the boat set up? Sounds like a fun Project.
As for downrange power. Is your J1 large enough and powerful enough? Don't just go a bigger main and then de-tune to stop weather helm its an arse about way of trying to increase speed. All you end up is a positive effect from more area and not any Aerodynamic advantage.
#4
Posted 15 June 2012 - 10:32 AM
#5
Posted 15 June 2012 - 11:25 AM
Why not bang on a max size jib taking into account your new spreader arrangement, that is an easy way to up the horsepower in the light, and you can always change it when the breeze comes up? Roachy jibs seem to work pretty well on sportsboats, as they are so susceptible to choppy conditions due to the short length; the guys who did our jibs for the Shaws have really made a big difference in getting the boats going upwind.I'm updating a Holder 20 ( OK, everybody laugh now and get it out of your system) and am considering a square top mainsail.
Up to now, I've added a sliding bowsprit and an asymmetrical spinnaker, and have modified the original rig by sweeping back and lengthening the spreaders and moving the shrouds outboard and back, eliminating the backstay.
I'm using a 100% blade jib and a fully battened VERY roachy main. the boat sails really well in a breeze and the modified rig seems very stable. The boat is a lot more fun to sail now than it was with the 155% genny since in a breeze the main works well without the 155 backwinding it.
Problem is, in light air, i'm missing the sail area I gave up by going from the 155 to the 100% jib. The larger main helps, but I want to add more area and have the mainsheet, vang and traveller capacity to ( I believe ) manage a square top main. I can accommodate a 24'6" luff and a 9'9" foot. I understand the center of effort / center of lateral resistance concept and can tweak mast position and rake accordingly. Right now the boat is well balanced with it's sail of those dimensions and lots of roach.
I know it's probably more practical to buy a different boat etc. etc. but playing around with this boat is fun and as much a hobby as a quest.
Can anyone suggest a good source for an appropriate mainsail? Looking for outside the box ideas as opposed to "Contact North Sails"
Thanks for any constructive ideas!
Paul
St. Augustine
I am not sure what you consider square top or big roach...but either way banging loads of main sail area up high onto a sportsboat then having to depower it can be a bit counterproductive if the rig isn't getting loads of power out of a well cut headsail.
I presume you have ditched any winches and are able to sheet the jib using rachet blocks etc....pulling weight out of everywhere is always a good way to go too.
#6
Posted 15 June 2012 - 11:28 AM
Contact any loft that you have seen make a good sail. Don't let them treat you like a nobody just because you have a 20 footer. your money is worth the same as anybody's.
Got any Pics of the boat set up? Sounds like a fun Project.
As for downrange power. Is your J1 large enough and powerful enough? Don't just go a bigger main and then de-tune to stop weather helm its an arse about way of trying to increase speed. All you end up is a positive effect from more area and not any Aerodynamic advantage.
I'm afraid you've lost me there "Aerodynamic Advantage". The "J" is 7.25, same as the original rig. I'm using a jib from an SR Max 21 which is full hoist and has a foot of 7.25. It completely fills the foretriangle and sheets nicely close to the deck.
The boat was originally rated for a 155, so I'm moving the CE forward by eliminating the overlap and hope that will offset the extra main.
I'll get some photos up when the new main is on.
Thanks for the input!
Paul
#7
Posted 15 June 2012 - 11:37 AM
Why not bang on a max size jib taking into account your new spreader arrangement, that is an easy way to up the horsepower in the light, and you can always change it when the breeze comes up? Roachy jibs seem to work pretty well on sportsboats, as they are so susceptible to choppy conditions due to the short length; the guys who did our jibs for the Shaws have really made a big difference in getting the boats going upwind.
I'm updating a Holder 20 ( OK, everybody laugh now and get it out of your system) and am considering a square top mainsail.
Up to now, I've added a sliding bowsprit and an asymmetrical spinnaker, and have modified the original rig by sweeping back and lengthening the spreaders and moving the shrouds outboard and back, eliminating the backstay.
I'm using a 100% blade jib and a fully battened VERY roachy main. the boat sails really well in a breeze and the modified rig seems very stable. The boat is a lot more fun to sail now than it was with the 155% genny since in a breeze the main works well without the 155 backwinding it.
Problem is, in light air, i'm missing the sail area I gave up by going from the 155 to the 100% jib. The larger main helps, but I want to add more area and have the mainsheet, vang and traveller capacity to ( I believe ) manage a square top main. I can accommodate a 24'6" luff and a 9'9" foot. I understand the center of effort / center of lateral resistance concept and can tweak mast position and rake accordingly. Right now the boat is well balanced with it's sail of those dimensions and lots of roach.
I know it's probably more practical to buy a different boat etc. etc. but playing around with this boat is fun and as much a hobby as a quest.
Can anyone suggest a good source for an appropriate mainsail? Looking for outside the box ideas as opposed to "Contact North Sails"
Thanks for any constructive ideas!
Paul
St. Augustine
I am not sure what you consider square top or big roach...but either way banging loads of main sail area up high onto a sportsboat then having to depower it can be a bit counterproductive if the rig isn't getting loads of power out of a well cut headsail.
I presume you have ditched any winches and are able to sheet the jib using rachet blocks etc....pulling weight out of everywhere is always a good way to go too.
Haven't calculated the exact numbers yet on the size of the square top. The goal is to restore lost sail area.
That's a good suggestion about the larger jib. The 135 that I have for it might still fit. I'll give that a try, and have a look at some sport boat rigs to see what I might be missing (aside from a real sport boat, that is ;-) I still have the winches aboard, even though we bowstring the jib sheets using two cam cleats. I need at least one winch to raise the keel and also use them to tension the halyards. The boat weighs in at 1160# and is sailed as light as possible.
Thanks,
Paul
#8
Posted 15 June 2012 - 12:37 PM
#9
Posted 15 June 2012 - 12:55 PM
A 2 head sail inventory isn't to much to tackle. A 0-9 knot J1 would weigh in at no more than 7-10kgs, bag and all. Not a huge dent in performance when you consider the gains made from having the right sail up! Alternatively, look at the forecast and leave one on the dock if you know its not going to be used.
#10
Posted 15 June 2012 - 02:43 PM
#11
Posted 15 June 2012 - 03:12 PM
http://www.latellsails.com/
Attached Files
#12
Posted 15 June 2012 - 03:52 PM
Why not bang on a max size jib taking into account your new spreader arrangement, that is an easy way to up the horsepower in the light, and you can always change it when the breeze comes up? Roachy jibs seem to work pretty well on sportsboats, as they are so susceptible to choppy conditions due to the short length; the guys who did our jibs for the Shaws have really made a big difference in getting the boats going upwind.
I'm updating a Holder 20 ( OK, everybody laugh now and get it out of your system) and am considering a square top mainsail.
Up to now, I've added a sliding bowsprit and an asymmetrical spinnaker, and have modified the original rig by sweeping back and lengthening the spreaders and moving the shrouds outboard and back, eliminating the backstay.
I'm using a 100% blade jib and a fully battened VERY roachy main. the boat sails really well in a breeze and the modified rig seems very stable. The boat is a lot more fun to sail now than it was with the 155% genny since in a breeze the main works well without the 155 backwinding it.
Problem is, in light air, i'm missing the sail area I gave up by going from the 155 to the 100% jib. The larger main helps, but I want to add more area and have the mainsheet, vang and traveller capacity to ( I believe ) manage a square top main. I can accommodate a 24'6" luff and a 9'9" foot. I understand the center of effort / center of lateral resistance concept and can tweak mast position and rake accordingly. Right now the boat is well balanced with it's sail of those dimensions and lots of roach.
I know it's probably more practical to buy a different boat etc. etc. but playing around with this boat is fun and as much a hobby as a quest.
Can anyone suggest a good source for an appropriate mainsail? Looking for outside the box ideas as opposed to "Contact North Sails"
Thanks for any constructive ideas!
Paul
St. Augustine
I am not sure what you consider square top or big roach...but either way banging loads of main sail area up high onto a sportsboat then having to depower it can be a bit counterproductive if the rig isn't getting loads of power out of a well cut headsail.
I presume you have ditched any winches and are able to sheet the jib using rachet blocks etc....pulling weight out of everywhere is always a good way to go too.
Haven't calculated the exact numbers yet on the size of the square top. The goal is to restore lost sail area.
That's a good suggestion about the larger jib. The 135 that I have for it might still fit. I'll give that a try, and have a look at some sport boat rigs to see what I might be missing (aside from a real sport boat, that is ;-) I still have the winches aboard, even though we bowstring the jib sheets using two cam cleats. I need at least one winch to raise the keel and also use them to tension the halyards. The boat weighs in at 1160# and is sailed as light as possible.
Thanks,
Paul
Randy Smyth says Let' start with the obvious: Squaretop mains look bigger than pinheads. Sail area can generally be expanded by 7 percent with a squaretop profile.
#13
Posted 15 June 2012 - 06:14 PM
#14
Posted 16 June 2012 - 12:14 AM
Paul
#15
Posted 18 June 2012 - 08:35 PM
I think you're going to get more useful range from a square top than you will from two jibs on a fractional rig. It's not just about the extra sail area, it's about the efficiency of that sail area. The head of the main on a holder is going to be projected what,about 2 feet above the head of the jib? With an aerodynamic profile that eliminates the tip vortex and gives lift where you want it - high up in the cleanest air the boat's going to see. It doesn't have to be a radical head on the main, either, to get that performance change.
It's not the size of the jibs that make a difference, it's the shape. Having only 1 sail to do everything is a very brave way to go. It works in OD because everyone is only using one jib ala J22. But if you are doing handicap racing then you need to be able to get proper shapes out of your sails. A J1 will be much deeper and more powerful than a J2 or 3. Do you need 3-4 different headsails? Probably not, but at least 2, 3 would be nice. Cost is always a consideration, but size of the sails can makes it a little easier to do. With 1 jib you will be compromising in just about every condition.
#16
Posted 09 September 2012 - 09:07 PM
Finally got it built! Used my new square top main for the first time in a light air PHRF race. sail looks great and helped in the light conditions. Has a 28" head and gives me an extra 20 sq. ft over the stock main (120 - 140 sq. ft.) Boat balance seemed fine upwind in about 5-6 knots. Too light for any definitive judgement, of course. Looking forward to getting some time in on it in a little more wind and getting dialed in on the trim.
Quotes for the sail ran the gamut from a high of $4200 to a low of $1100. All quoted sails used one form or another of a laminate material. I settled on the $1100 sail, which was almost a gift from my sailmaker who makes all the sails for my other, one design, boat.
I'll update this topic from time to time, whether good or bad results.
Paul
#17
Posted 10 September 2012 - 01:26 AM
Pic # 2 dacron less rad Venture 21 OD sails same idea.
pics of yur girlfriends tits would be nice...
Attached Files
#18
Posted 10 September 2012 - 03:06 AM
Pic #1 kevlar i 550 Banks sails Sq. top. Roachy 100% Jib
Pic # 2 dacron less rad Venture 21 OD sails same idea.
pics of yur girlfriends tits would be nice...
Look close; the Portland i550 sails have the N over S logo of North Sails - Portland loft.
i550-portland 1-crop.jpg 39.29K
43 downloads
DSC_0015-60.jpg 154.78K
47 downloadsThere is a new set of Farrar Sails on Phil’s Boat.
We are still waiting at this late hour, for his report on a possible build status change. ??????
Driveway%20Sailing1.jpg 375.88K
41 downloadsDuncan has been racing in Florida with a set of M20 Quantum sails.
i550-172.jpg 116.71K
32 downloadsTwo Great Lakes i550s outfitted with different flat top designs from MAD sails.
Ron has I550-108 for sale. Great price for someone wanting to get into an i550.
DSC_62121.JPG 59.24K
26 downloads
#19
Posted 10 September 2012 - 08:29 PM
Pic #1 kevlar i 550 Banks sails Sq. top. Roachy 100% Jib
Pic # 2 dacron less rad Venture 21 OD sails same idea.
pics of yur girlfriends tits would be nice...
Look close; the Portland i550 sails have the N over S logo of North Sails - Portland loft.i550-portland 1-crop.jpg 39.29K 43 downloads
DSC_0015-60.jpg 154.78K 47 downloads
One of the PDX boats is using main and jib from Banks designed locally. The rest are using North Sails.
The North Sails are Dacron (except for the "trial" sails which were from ultra light 49'er cloth).
The Banks sails are an Aramid paneled sail.
Since this was our first set of sails we went with Dacron to work out any bugs in the shape and design. So far it would appear that the Banks sails are faster in light air and drifting conditions.
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