Don: I keep reading your posts about Hunters having difficulty with sail trim and that they sail differently than other boats. I beg to differ. They are no different than any other fractional rig, compariable to higher performance boats. I've sailed J24s, and find them similar(mast bend, rake, controls). I have your charts and book, and I have found that your 4 basics of trim are working very well, especially properly setting up the twist in the main and using the traveler to change the angle of attack. I've also discovered that mid boom sheeting (older Hunter with no arch) makes flatting the sail more difficult which makes a huge difference in higher winds. Adding another purchase helps, or even pulling down on the end of the boom to set up the proper depth and twist! Angle of attack and sail depth is especially important on a Hunter, since they are designed with a large main as the primary power provider (as opposed to many boats with large Genoas) I can now sail with full canvas in 18 to 20 knots before going to a reef, and I used to reef at about 14 to 15! The newer Hunters are a B & R rig: no backstay (or adjuster), swept back spreaders, diamond shrouds. Prior Hunters are a Bergstrom rig, (7/8 fractional rig, double swept back spreaders) so they have a backstay, and an adjuster can be easily installed. Even with the adjuster, you can only play with the the very top portion of the mast, since the double spreaders keep both the mast bend and the rake pretty much fixed. If the rig is properly tuned, however, even this little bit of play can be used effectively. Likewise, the Cunningham that people say is missing is a function of the sailmaker, not Hunter. I have one on my main, but had to intall a block w/cam cleat at base of the mast to use it, no big deal. Hunters are tuned with both mast bend and rake, both of which move the center of resistance aft and introduce weather helm. It can become excessive, especially with a Genoa, which is really too much foresail for the rig design except for light air. After tuning my rig and reading a lot in the forum archives, I've come to believe that many Hunters are tuned with both too much bend and especially too much rake. The best source for learing about this is BrionToss.com, or his great tuning video. Hunters are designed with a large main, and probably do best with a 100 to 110 jib and an assemetrical/gennaker for downwind or light air. My '90 Hunter had a large Genoa on it when I bought it two years ago. Last winter I switched it with the unused(!) 110 that came with the boat. This alone removed most of the excessive weather helm. And except in very light air, the boat performs better with the smaller headsail. Also, the flatter the boat the faster it goes---so I try to keep my heeling at 20 degrees. At or above 30 degrees, weather helm is excessive and the hull shape is distorted in the water. Better to reef or use your techniques. So to Hunter owners, I would say: 1. Make sure your rig is properly tuned. For newer B & R rigs with no back stay, there is a a detailed article in the Reference Library for proper tuning. For older Hunters, get Brion Toss's "Tuning Your Rig" upon which he features a Hunter Bergrom Rig. 2. Master the 4 elements of sail trim, use the controls you have, add the ones you don't. 3. Use the canvass that is designed for the rig---large main, smaller jib (eschew the Genoa), assymetric spinnaker for ease of handling and downwind performance. 3. Sail the boat flat, and outsail the Catalinas around you!
- Status
Gee, Thanks Dean...
.. I just dropped a hundred bucks on their videos... .. I was going to consider a 130 Genny. Now you have me reconsidering. Still, our conditions are pretty light around here and if it's reefable.. Rick D.
.. I just dropped a hundred bucks on their videos... .. I was going to consider a 130 Genny. Now you have me reconsidering. Still, our conditions are pretty light around here and if it's reefable.. Rick D.
Tuning article
Dean, where do I find the reference article you mentioned on tuning the B&R rig? Thanks. George
Dean, where do I find the reference article you mentioned on tuning the B&R rig? Thanks. George
Tuning Article
On HunterOwners.com, click on.... "More Fun" tab... "Reference Library" "Tuning the B & R Rig"
On HunterOwners.com, click on.... "More Fun" tab... "Reference Library" "Tuning the B & R Rig"
130 Genny
Rick, I have a 130, just don't use it much anymore, though there are times in 5 to 10 knots I wish I had it bent on (August & September around here). Mine really shouldn't be used while partially furled--its not a true reef--for any extended period of time, and not in heavy air, when I'd most likely need it. The cloth simply won't take the strain, and my continuous line furler might not either (most furling lines are pretty light). You probably know newer Gennies have actual reef "points" built into them---heavier cloth or foam backing. If I was going to use mine all of the time, I'd tune the rig with less bend and rake. That would move the center of resistance foward, and reduce weather helm. With a Genny actually built for reefing at 110 and a little tuning you might get the best of both worlds....
Rick, I have a 130, just don't use it much anymore, though there are times in 5 to 10 knots I wish I had it bent on (August & September around here). Mine really shouldn't be used while partially furled--its not a true reef--for any extended period of time, and not in heavy air, when I'd most likely need it. The cloth simply won't take the strain, and my continuous line furler might not either (most furling lines are pretty light). You probably know newer Gennies have actual reef "points" built into them---heavier cloth or foam backing. If I was going to use mine all of the time, I'd tune the rig with less bend and rake. That would move the center of resistance foward, and reduce weather helm. With a Genny actually built for reefing at 110 and a little tuning you might get the best of both worlds....
Hunter 35
Appreciate your info on how you sail your boat. Could you provide more info on how you set your mast rake ?? I have had the mast on and off my Hunter Legend 35 three times in the past six months in an effort to find the best rake setting. If I remember right Brion Toss never does address mast rake in his video in the section re: the onboard tuning segment onboard the Hunter. He works on the side stays onl;y. From his email traffic, Brion admitts to being a tuner for cruising sail boats - not boats for the performance sailor. It is my understandig that the wind speed determins the sails in use. Down here on the Gulf I need the 150 on low wind days to stay up with traffic. I have a new 120 for windy days. Bob Dean
Appreciate your info on how you sail your boat. Could you provide more info on how you set your mast rake ?? I have had the mast on and off my Hunter Legend 35 three times in the past six months in an effort to find the best rake setting. If I remember right Brion Toss never does address mast rake in his video in the section re: the onboard tuning segment onboard the Hunter. He works on the side stays onl;y. From his email traffic, Brion admitts to being a tuner for cruising sail boats - not boats for the performance sailor. It is my understandig that the wind speed determins the sails in use. Down here on the Gulf I need the 150 on low wind days to stay up with traffic. I have a new 120 for windy days. Bob Dean
Mast rake
Remember that bend and rake are two different things. Bend (sometimes called "pre-bend") is the same as the amount of bow---like an archer's bow. If you have a B&R rig with diamond spreaders, you can prebend the mast before it is stepped. My Hunter 30 doesn't have diamond speaders, so I have to use the shrouds to hold the bend in place. Brion Toss says bend should be about the thickness (diamter) of the mast, say five or six inches. The book I referred to in the thread above says 1.5 times mast diameter not to exceed 2% of the distance between the deck and mast forestay fitting (the "I" measurement) So on my H30, thats a range of 5" (Toss's mast thickness) to 8.84" (2% of "I"). Steve Dion sent me to a page of a H31 manual (See HOW Talk forum, "Glad to see you Phil) which says desired mast bend is 1% of mast height above the boom (P)--- on my H30, that would be just under 5". You measure prebend by stretching your main halyard to the boom fitting on the mast intersection of the mast and boom. You know have what looks like an archer's bow, and you estimate the distance between the "string" (the halyard) and the bow (the mast) at the maximum point, which theoretically would be half way up the mast. Rake is how far the whole rig "leans" aft. According to George above, Hunter recommends up to 5 degrees or rake (which I've also heard). My tuning books says .5 to 1 degree for masthead rigs; 2 to 3 degrees for fractional rigs. Remember, on a Bergstrom rig with swept back spreaders, bend is controlled by the spreaders, rake by forestay tension. Once the rig is tuned, the backstay does almost nothing. In the video, Toss uses an adjustable backstay to put the initial BEND in the mast, and then he holds it there by adjusting the shrouds. He also says that on a rig like this (fractional), the adjuster can only affect the very top of the mast, since the rest of the mast is held tightly in place by the shrouds running over at least two sets of spreaders. In contrast, on a masthead rig (Catalina), the whole rig is easily moved fore and aft with an adjuster because the shrouds are in the same plane as the mast. Rake is measured by attaching a weight to the main halyard, letting it hang freely from the masthead, and measuring the distance between the weight and the mast at the boom fitting (Distance from masthead to boom fitting is "P", same as the mainsail luff). To figure how many inches back from the mast equals a degree, you figure the length of "P" as the radius of a circle (P x Pi), then the circumference of such circle divided by 360. On my H30, "PP=40'7" or 487", times pi = 1530" divided by 360 = 4.25" So 3 degrees of rake would be 11.75" In the "Glad to see you Phil" thread mentioned above, one posting suggests 3 to 5 degrees. The H31 manual says: "Adjust the forestay and backstay to obtain the desired rake. The mast should be vertical or raked aft. The more rake, the greater the weather helm. The forestay and backstay should have a reasonable amount of tension on them (whatever that is!)" I have just installed a splitback stay adjuster. I'm going to re-tune my rig with 3 degrees of rake with the adjuster fully applied. I'm hoping to reach degrees vertical with the adjuster fully off, but won't know until I can measure it. All of this might be helpful with a 130 Genoa, since it moves the center of effort aft. With the adjuster off, the mast will stand more vertical,moving the center of resistance forward, and reducing weather helm. Of course you can't know any of this for sure until you play with it.... Meanwhile, I'm a little perplexed as to why you've had you mast off your boat so many times trying to get the right bend. You don't have to remove the mast to put bend in it. Perhaps you could say more....
Remember that bend and rake are two different things. Bend (sometimes called "pre-bend") is the same as the amount of bow---like an archer's bow. If you have a B&R rig with diamond spreaders, you can prebend the mast before it is stepped. My Hunter 30 doesn't have diamond speaders, so I have to use the shrouds to hold the bend in place. Brion Toss says bend should be about the thickness (diamter) of the mast, say five or six inches. The book I referred to in the thread above says 1.5 times mast diameter not to exceed 2% of the distance between the deck and mast forestay fitting (the "I" measurement) So on my H30, thats a range of 5" (Toss's mast thickness) to 8.84" (2% of "I"). Steve Dion sent me to a page of a H31 manual (See HOW Talk forum, "Glad to see you Phil) which says desired mast bend is 1% of mast height above the boom (P)--- on my H30, that would be just under 5". You measure prebend by stretching your main halyard to the boom fitting on the mast intersection of the mast and boom. You know have what looks like an archer's bow, and you estimate the distance between the "string" (the halyard) and the bow (the mast) at the maximum point, which theoretically would be half way up the mast. Rake is how far the whole rig "leans" aft. According to George above, Hunter recommends up to 5 degrees or rake (which I've also heard). My tuning books says .5 to 1 degree for masthead rigs; 2 to 3 degrees for fractional rigs. Remember, on a Bergstrom rig with swept back spreaders, bend is controlled by the spreaders, rake by forestay tension. Once the rig is tuned, the backstay does almost nothing. In the video, Toss uses an adjustable backstay to put the initial BEND in the mast, and then he holds it there by adjusting the shrouds. He also says that on a rig like this (fractional), the adjuster can only affect the very top of the mast, since the rest of the mast is held tightly in place by the shrouds running over at least two sets of spreaders. In contrast, on a masthead rig (Catalina), the whole rig is easily moved fore and aft with an adjuster because the shrouds are in the same plane as the mast. Rake is measured by attaching a weight to the main halyard, letting it hang freely from the masthead, and measuring the distance between the weight and the mast at the boom fitting (Distance from masthead to boom fitting is "P", same as the mainsail luff). To figure how many inches back from the mast equals a degree, you figure the length of "P" as the radius of a circle (P x Pi), then the circumference of such circle divided by 360. On my H30, "PP=40'7" or 487", times pi = 1530" divided by 360 = 4.25" So 3 degrees of rake would be 11.75" In the "Glad to see you Phil" thread mentioned above, one posting suggests 3 to 5 degrees. The H31 manual says: "Adjust the forestay and backstay to obtain the desired rake. The mast should be vertical or raked aft. The more rake, the greater the weather helm. The forestay and backstay should have a reasonable amount of tension on them (whatever that is!)" I have just installed a splitback stay adjuster. I'm going to re-tune my rig with 3 degrees of rake with the adjuster fully applied. I'm hoping to reach degrees vertical with the adjuster fully off, but won't know until I can measure it. All of this might be helpful with a 130 Genoa, since it moves the center of effort aft. With the adjuster off, the mast will stand more vertical,moving the center of resistance forward, and reducing weather helm. Of course you can't know any of this for sure until you play with it.... Meanwhile, I'm a little perplexed as to why you've had you mast off your boat so many times trying to get the right bend. You don't have to remove the mast to put bend in it. Perhaps you could say more....
Thoughts About Hunter Sai Trim
Dean: Excellent, excellent article!! I'm printing it to use as a reference. Also, thank you for your kind words about my book and chart. Actually, I've never said Hunters are hard to trim. It is the Hunter owners that seem to be complaining about the inability to properly trim the sails and I can't imagine why they are having the problems they outline. In fact, and sadly, I've never had the opportunity to sail on a Hunter to experience what they are talking about. There is a Hunter about 6 slips away from me that I would love to sail but I never see the owner and I am at my boat frequently (I'm retired). I use that Hunter as my test model. When Hunter owners present me with problems with the boats rig that I don't exactly understand, I go over to this guys boat and ponder the question. The boat came in handy concerning the recent traveler question. Once I saw how the traveler was set up, I could see the problem with the mainsheet pulling angle. I think all your advise is right on the mark - understand and master the 4 elements of sail trim and "use the controls you'se got's". I have a Catalina 30 and as you know, anytime there are 2 boats on the water you have a race and sometimes I seek out the Hunters to give them a friendly "go". When a boat comes up on me, I generally relax the sails - to sucker them in - and, when they are next to me I trim up for speed. The Hunter owners I encounter in Long Beach, are easy prey as they don't seem to be into sail trim. They keep the settings they have and watch me go by. I almost want to shout over to them that they should do this or that to make the boat sail more efficiently.
Dean: Excellent, excellent article!! I'm printing it to use as a reference. Also, thank you for your kind words about my book and chart. Actually, I've never said Hunters are hard to trim. It is the Hunter owners that seem to be complaining about the inability to properly trim the sails and I can't imagine why they are having the problems they outline. In fact, and sadly, I've never had the opportunity to sail on a Hunter to experience what they are talking about. There is a Hunter about 6 slips away from me that I would love to sail but I never see the owner and I am at my boat frequently (I'm retired). I use that Hunter as my test model. When Hunter owners present me with problems with the boats rig that I don't exactly understand, I go over to this guys boat and ponder the question. The boat came in handy concerning the recent traveler question. Once I saw how the traveler was set up, I could see the problem with the mainsheet pulling angle. I think all your advise is right on the mark - understand and master the 4 elements of sail trim and "use the controls you'se got's". I have a Catalina 30 and as you know, anytime there are 2 boats on the water you have a race and sometimes I seek out the Hunters to give them a friendly "go". When a boat comes up on me, I generally relax the sails - to sucker them in - and, when they are next to me I trim up for speed. The Hunter owners I encounter in Long Beach, are easy prey as they don't seem to be into sail trim. They keep the settings they have and watch me go by. I almost want to shout over to them that they should do this or that to make the boat sail more efficiently.
Let's Get Don on a Hunter....
Don: I've seen you comment before that you've not been on a Hunter. C'mon Hunter Owners, isn't there somebody in the LA area that can take Don out, so he can see and solve all the fuss? Or come up to Seattle for a weekend, and I'll take you out on mine, plus hit the guys up at Signature Yachts for a demo cruise on several. Meanwhile I've trusted your writing and teaching so far, but am now alarmed at your inclusion of fish tales (A Catalina sailing away from a Hunter????) on what once was a credible "expert forum...." What does a Catalina look like from the stern, anyway?
Don: I've seen you comment before that you've not been on a Hunter. C'mon Hunter Owners, isn't there somebody in the LA area that can take Don out, so he can see and solve all the fuss? Or come up to Seattle for a weekend, and I'll take you out on mine, plus hit the guys up at Signature Yachts for a demo cruise on several. Meanwhile I've trusted your writing and teaching so far, but am now alarmed at your inclusion of fish tales (A Catalina sailing away from a Hunter????) on what once was a credible "expert forum...." What does a Catalina look like from the stern, anyway?
Let's Get Don On A Hunter
Dean: I hope someone responds with a test drive on a Hunter but as to what a Catalina looks like from the stern - what you'd see is my boat name "Yankee" getting smaller and smaller as I pull away. Sort of like watching the number of football playing get smaller and smaller after you missed a tackle. A lot of people ask me how I came up with the name Yankee, which has been the name of every boat I've owned. They think it is because I'm originally from RI but it isn't. As A kid growing up in RI in the late 40's and early 50's (before TV), I lived my sailing experience through the pages of National Geographic, especially the exploits of Irving Johnson on his boat "Yankee". I pictured myself on the deck of his boat sailing with him on his adventures. My first boat was a small sailing dingy I dug from the sand after a hurricane and repaired. I named it Yankee and every boat I've owned since, even high speed jet race boats have carried that name. Sometimes, when I get a new boat, I think about changing the name but I never do. Incidently, two of Irving Johnson boats have been recreated here in San Pedro, Ca. I enjoyed going down and walking their decks when they were under construction.It brought me back to years ago thumbing throught National Geographic.
Dean: I hope someone responds with a test drive on a Hunter but as to what a Catalina looks like from the stern - what you'd see is my boat name "Yankee" getting smaller and smaller as I pull away. Sort of like watching the number of football playing get smaller and smaller after you missed a tackle. A lot of people ask me how I came up with the name Yankee, which has been the name of every boat I've owned. They think it is because I'm originally from RI but it isn't. As A kid growing up in RI in the late 40's and early 50's (before TV), I lived my sailing experience through the pages of National Geographic, especially the exploits of Irving Johnson on his boat "Yankee". I pictured myself on the deck of his boat sailing with him on his adventures. My first boat was a small sailing dingy I dug from the sand after a hurricane and repaired. I named it Yankee and every boat I've owned since, even high speed jet race boats have carried that name. Sometimes, when I get a new boat, I think about changing the name but I never do. Incidently, two of Irving Johnson boats have been recreated here in San Pedro, Ca. I enjoyed going down and walking their decks when they were under construction.It brought me back to years ago thumbing throught National Geographic.
Dean Strong: In a recent post I said I was going to print your excellent article but I didn't right away and now I can't find it. I'm hoping you saved a copy because I could really use it as reference material for a seminar I'm conducting in the near future. Invariably, there are Hunter owners there and your piece would be very helpful to me. If you have it, could you Email it to me at yankee3223@juno.com. Thank you.
Fractional tuning
To all, 20 Dec 2002 Needed a few days to prepare this reply on mast tuning. Hope we have not lost too many readers because of this delay It seems that when we discuss mast tuning in this section some try to touch all bases. The current crop of sail boats has three basic rigs – the fractional, the mast head and Hunter’s current use of the B&R concept. My HL 35 is a fractional rig. I have had no experience with tuning a mast head or any other type of rig. As such all the info provided below is for the Hunter fraction rig. First off I was asked as to why I have had the mast on and off my Hunter 35 these past few months. First time was to modify the mast with new leads and to change out the roller furler system (Hood S/L to the ProFurl 35). The second time I had to replace the wind bird and needed to make a special fitting to hold the new mast head wind bird assembly. The last steep was to replace damaged electrical wires and pull a few new halyards. Mixed in with this effort was a task to establish the optimum length of the forestay for the proper mast rake. I estimate that I have changed the length of the forestay six times in the past six months to determine a mast rake that seems right to me. With this forestay project went the additional task of setting and resetting side stay tensions and mast pre bend (six times). Adjusting my forestay turnbuckle was made difficult because the roller furler was in place and covered the turnbuckle while underway. For my HL 35 fractional rig there is a decided difference between mast pre bend and mast bend. Pre bend is the fixed bend set to the mast in the tuning phase for a fractional rig. On my mast, pre bend is a combination of the bend induced by tuning the side stays and by adjusting the back stay turnbuckles. This pre bend is the amount of mast bend measured with the main halyard led from the tip of the mast to the boom junction point. My mast is 50 feet in length and is stepped on top of the cabin deck. With the main halyard set taunt to the boom/mast junction I look for a 4.5 inch pre bend bow. This 4.5 inch gap of mast pre bend set, is the luff curve of my mainsail sewn in by my sail maker. The sail maker’s luff curve is a sail maker’s design effort and has little to do with the Brion Toss rule of thumb associated with mast thickness etc. As to a straight stick mast head rig, pre bend does not seem to be a necessary set. I have been told that for a mast head rig the sail maker does in fact design in a luff curve. With my HL35 fractional rig I induce mast bend with my back stay adjuster while under sail. Mast bend is used to flatten the mail sail of a fractional rig while on a point to a mark, close on the wind. A major factor in the ability of a sailboat with a fractional rig to point is head stay sag. The tighter the head stay the better the point. With a fractional rig the head stay hound (attaching point) is usually set well below the mast head. On my HL 35 it is six feet below the mast head. As such any tension induced by my adjustable back stay only bends the top of the mast and thus flattened out the sail. On my Hunter 35 neither the back stay turn buckles nor the back stay adjuster affect the forestay tension to any noticeable degree. The most effective way I know of to take out head stay sag is to install running back stays. Running back stays are another set of mast leads that are imbedded in the aft side of the mast - level with the hound. These leads, one each side are led aft on the deck to a set of pulleys very near the stern and then to a means of inducing a great deal of tension (read big winch). When installed, you will notice a major improvement in pointing when the running back stay on the windward side is set. In a recent reply, the subject of mast rake was discussed. On my HL 35 I have induced or set what I consider 1.5 degrees of rake. I measured this rake on the boom with the main halyard touching the boom at 15 inches of travel from the mast. In my discussion with the Hunter factory they recommend 10 inches of main halyard travel – which according to my calculations is 1 degree of rake. I measure this 15 inches of main halyard travel on the boom with the mast in a straight up and down configuration - before the pre bend is induced. If I measure the main halyard travel on the boom after pre bend is induced I believe it is not a true indication of mast rake as the mast has a bend in it. In this final mast tension configuration it is what you might call “theoretical” mast rake. The only really effective way of judging this “theoretical” mast rake is to talk to the main sail and see if she likes the set. And of course there is the overall performance of the boat. This is of course the final determination of the mast rake setting - performance. Brion Toss may have did it but I found it most difficult to induce mast pre bend with the back stay turnbuckles and then tune the side stays to the proper setting. What I do after the length of the forestay is determined is to set side stay tension – ignoring the back stay setting. For the side stay turn buckle settings I use a set of calipers and measure the distance between the turnbuckle internal posts. I use this number to keep the side stays even. That is, if I have 72mm on one side I adjust the sister side stay on the other side to this setting while using The Brion Toss “tuning fork” approach to determine proper tension. I have of course determined that the lower turn buckle posts attached to the deck have the exact same vertical height on each side. Which they do on my boat. We ran an Excel spread sheet on the 10% and 12% tension setting for the various size stainless steel wire shrouds installed on my Hunter Legend 35. We used a Loose tension gage to check these numbers and found that once you hear the “twang” of a shroud in proper tension it is not to hard to reproduce. As to the proper tension of the head stay – you really do not have much control over it. With my fractional rig once the side stay tension is set, it is best not to try and re set the tension in the forestay as any change there will most definitely affect the side stay tensions. For a fractional rig, once the desired length of the forestay is set and the side stay tensions are set, there is a designed pre bend in the mast induced by the swept back spreader bars (two sets). However this side stay induced pre bend is not enough to meet my sail maker’s requirement for a 4.5 inch luff curve. As such, with the back stay adjuster in the full off (up) position, I then adjust the back stay turnbuckles. It is not a lot of back stay turn buckle take up adjustment, but some take up is needed. In summary the project of mast tuning is a most interesting exercise. I am sure I have only scratched the surface of this art. It, like every other boat project requires a high degree of attention to detail. As stated above, this info is for a fractional rig Hunter. I would request that when the Hunter sailors write in about mast tuning that they identify the type of rig on their boat – it makes it much easier to understand the issue. Hope this helps. Be more than happy to answer any question you may have. R Dean
To all, 20 Dec 2002 Needed a few days to prepare this reply on mast tuning. Hope we have not lost too many readers because of this delay It seems that when we discuss mast tuning in this section some try to touch all bases. The current crop of sail boats has three basic rigs – the fractional, the mast head and Hunter’s current use of the B&R concept. My HL 35 is a fractional rig. I have had no experience with tuning a mast head or any other type of rig. As such all the info provided below is for the Hunter fraction rig. First off I was asked as to why I have had the mast on and off my Hunter 35 these past few months. First time was to modify the mast with new leads and to change out the roller furler system (Hood S/L to the ProFurl 35). The second time I had to replace the wind bird and needed to make a special fitting to hold the new mast head wind bird assembly. The last steep was to replace damaged electrical wires and pull a few new halyards. Mixed in with this effort was a task to establish the optimum length of the forestay for the proper mast rake. I estimate that I have changed the length of the forestay six times in the past six months to determine a mast rake that seems right to me. With this forestay project went the additional task of setting and resetting side stay tensions and mast pre bend (six times). Adjusting my forestay turnbuckle was made difficult because the roller furler was in place and covered the turnbuckle while underway. For my HL 35 fractional rig there is a decided difference between mast pre bend and mast bend. Pre bend is the fixed bend set to the mast in the tuning phase for a fractional rig. On my mast, pre bend is a combination of the bend induced by tuning the side stays and by adjusting the back stay turnbuckles. This pre bend is the amount of mast bend measured with the main halyard led from the tip of the mast to the boom junction point. My mast is 50 feet in length and is stepped on top of the cabin deck. With the main halyard set taunt to the boom/mast junction I look for a 4.5 inch pre bend bow. This 4.5 inch gap of mast pre bend set, is the luff curve of my mainsail sewn in by my sail maker. The sail maker’s luff curve is a sail maker’s design effort and has little to do with the Brion Toss rule of thumb associated with mast thickness etc. As to a straight stick mast head rig, pre bend does not seem to be a necessary set. I have been told that for a mast head rig the sail maker does in fact design in a luff curve. With my HL35 fractional rig I induce mast bend with my back stay adjuster while under sail. Mast bend is used to flatten the mail sail of a fractional rig while on a point to a mark, close on the wind. A major factor in the ability of a sailboat with a fractional rig to point is head stay sag. The tighter the head stay the better the point. With a fractional rig the head stay hound (attaching point) is usually set well below the mast head. On my HL 35 it is six feet below the mast head. As such any tension induced by my adjustable back stay only bends the top of the mast and thus flattened out the sail. On my Hunter 35 neither the back stay turn buckles nor the back stay adjuster affect the forestay tension to any noticeable degree. The most effective way I know of to take out head stay sag is to install running back stays. Running back stays are another set of mast leads that are imbedded in the aft side of the mast - level with the hound. These leads, one each side are led aft on the deck to a set of pulleys very near the stern and then to a means of inducing a great deal of tension (read big winch). When installed, you will notice a major improvement in pointing when the running back stay on the windward side is set. In a recent reply, the subject of mast rake was discussed. On my HL 35 I have induced or set what I consider 1.5 degrees of rake. I measured this rake on the boom with the main halyard touching the boom at 15 inches of travel from the mast. In my discussion with the Hunter factory they recommend 10 inches of main halyard travel – which according to my calculations is 1 degree of rake. I measure this 15 inches of main halyard travel on the boom with the mast in a straight up and down configuration - before the pre bend is induced. If I measure the main halyard travel on the boom after pre bend is induced I believe it is not a true indication of mast rake as the mast has a bend in it. In this final mast tension configuration it is what you might call “theoretical” mast rake. The only really effective way of judging this “theoretical” mast rake is to talk to the main sail and see if she likes the set. And of course there is the overall performance of the boat. This is of course the final determination of the mast rake setting - performance. Brion Toss may have did it but I found it most difficult to induce mast pre bend with the back stay turnbuckles and then tune the side stays to the proper setting. What I do after the length of the forestay is determined is to set side stay tension – ignoring the back stay setting. For the side stay turn buckle settings I use a set of calipers and measure the distance between the turnbuckle internal posts. I use this number to keep the side stays even. That is, if I have 72mm on one side I adjust the sister side stay on the other side to this setting while using The Brion Toss “tuning fork” approach to determine proper tension. I have of course determined that the lower turn buckle posts attached to the deck have the exact same vertical height on each side. Which they do on my boat. We ran an Excel spread sheet on the 10% and 12% tension setting for the various size stainless steel wire shrouds installed on my Hunter Legend 35. We used a Loose tension gage to check these numbers and found that once you hear the “twang” of a shroud in proper tension it is not to hard to reproduce. As to the proper tension of the head stay – you really do not have much control over it. With my fractional rig once the side stay tension is set, it is best not to try and re set the tension in the forestay as any change there will most definitely affect the side stay tensions. For a fractional rig, once the desired length of the forestay is set and the side stay tensions are set, there is a designed pre bend in the mast induced by the swept back spreader bars (two sets). However this side stay induced pre bend is not enough to meet my sail maker’s requirement for a 4.5 inch luff curve. As such, with the back stay adjuster in the full off (up) position, I then adjust the back stay turnbuckles. It is not a lot of back stay turn buckle take up adjustment, but some take up is needed. In summary the project of mast tuning is a most interesting exercise. I am sure I have only scratched the surface of this art. It, like every other boat project requires a high degree of attention to detail. As stated above, this info is for a fractional rig Hunter. I would request that when the Hunter sailors write in about mast tuning that they identify the type of rig on their boat – it makes it much easier to understand the issue. Hope this helps. Be more than happy to answer any question you may have. R Dean
Forestay tension
Robert, an alternative to runners is a jumper strut on the front of the mast. I have one on my L35.5 and that allows me to tension the forestay with the backstay adjuster. Also no penalty to the handicap that runners carry.
Robert, an alternative to runners is a jumper strut on the front of the mast. I have one on my L35.5 and that allows me to tension the forestay with the backstay adjuster. Also no penalty to the handicap that runners carry.
Mast Jumper
Alan, I have heard of the mast jumper setup. Never seen one or know of a boat with it. Could you explain how it works ?? Do you have any pictures ?? Appreciate your interest in my info on tuning the Hunter fractional rig. Any other comments ?? Robert
Alan, I have heard of the mast jumper setup. Never seen one or know of a boat with it. Could you explain how it works ?? Do you have any pictures ?? Appreciate your interest in my info on tuning the Hunter fractional rig. Any other comments ?? Robert
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