EMAILS FROM MAY 2018
Posted on 17th November 2018 at 14:15
EMAILS FROM MAY 2018 WITH MR JIB FURLER – MALCOLM BLACKBURN
EMAILS FROM MAY 2018 WITH MR JIB FURLER – MALCOLM BLACKBURNHi MalcolmIn your role as Mr Jib Furler, I ask for some enlightenment please!Squib 745 which I share with Gill Lamb already had a jib furler when I bought in. I do like the peaceand quiet of a furler but I feel I don't point as well as other Squibs in our fleet which lack furlers. Youobviously don't have this problem or you wouldn't go so fast. I know that jib halyard tension, barberposition and tension and jib sheet tension all play their part but I can't seem to get the various parts inharmony. I'd really appreciate your advice if you could spare a minute.
BestRickyHi RickyPointing ability is often more in the mind than reality, as I find that other boats appear to be pointinghigher, yet people talk about me pointing high, so be careful not to get too paranoid as this can lead toyou pulling everything too tight and that certainly stops a Squib. I sail with the furler very similarly towithout, the only difference is that without the furler in heavy winds you can let off a bit more halyardso that the forestay starts to share the load with the jib halyard. With the furler because the jib is nothanked to the forestay, it is important that the forestay never takes any load.
I will start with a bit of science, then let’s see how we relate this to sailing. With the Squib rig beingset up slack, there is nothing to control the sag in the jib luff other than the mainsheet load orbackstay. If there is not much tension in the luff because there is not much mainsheet load, the act ofpulling in the jib causes more jib luff sag which makes the sail fuller so it backwinds and thus it doesnot point.
Pulling the jib in even harder simply makes things worse. Also I noticed about 3 years agoBatt started to make his jib with less luff curvature (flatter shape) and my 2017 Hyde I found hadsimilarly reduced the curvature. The impact of this is that the jib luff can sag a bit more and have thesame shape, thus needs less mainsheet tension to end up with the same pointing ability. If you haveone of the older fuller jibs this is not a problem, but it does need sailing differently, that is with moremainsheet tension.One effect of the furler is that the jib is set a little higher which can affect the sheeting angle and, forthe same barber position, can tighten the leach of the jib. Make sure the tack of the luff wire is fittedonto the drum without shackles.
The drum makes the jib luff wire about 60mm off the deck, but mostnon furlers use a shackle of at least 30mm, so the effect is not much, however you may want to putyour barbers about 30mm back from the sailmakers’ settings. However do not get too hung up on thisas mast rake influences jib sheeting angle more than you think.
Take care not to tighten the jibCunningham too tight. Leave it rather slack. People do not realize but when sailing in a blow the jibluff wire is under about 200lbs load and the wire stretches about 10mm, thus if the Cunningham is setjust tight at the loads on the mooring, the effect of the wire stretching tightens the Cunningham by10mm, not what you want. I tend to apply a lot of backstay pre start so that the mast does not flop about, it helps mepsychologically as it minimises the jib luff sag until you get on the beat and the mainsheet tensionright
Try doing this pre start set up.Sail on a beat with the mainsheetset as you would do for theconditions. Pull on the backstayuntil it has a little tension. Now letgo the jib and you may then needto put on a little more backstay.Now leave that backstay settingalone.Pull in the jib as you normallywould to the settings Hyde or Battgive for the Barbers. If when yousail against the other boats youfeel you are not pointing as high asthem, apply more mainsheettension.
This is the only controlyou have to control the jib sag tomake the jib flatter and thus pointhigher. You could try pulling thisin very hard just to see theinfluence that has on the pointingability. You will notice if you dothis that the backstay will nowbecome slack. That is because thewhole rig is stretching and themast rake is now increasing.Earlier I gave a figure for thestretch in the luff wire. Under thesame load the jib halyard andtensioning system will stretch by afurther 20mm at least. All thisstretch increases the mast rake,and alters the jib sheeting angle sothat there is less leach tension thusopening the leach.
This is kind of handy, because without you doing anything other than pulling themainsheet harder as the wind pipes up, the jib sheeting angle changes opening up the leach, which isjust what you want. If you think the jib is too open, release the mainsheet, tighten up your jib halyardto pull the mast forward, then pull in the mainsheet as hard as before.
Conversely if it’s not openenough let off the halyard. I believe that the reason that we have a favourite / optimum jib halyardsetting is because this gives the best jib sheeting angle, and thus the leach open the right amount,rather than the actual mast rake angle.I find that especially in lighter winds say up to force 2 that to get enough jib luff tension the mainsailis rather too tight in the leach. Be careful not to bring the traveller up too far as if the boom is on thecentre line it stalls out and does not drive the boat forwards, try to keep the end of the boom downfrom the centreline a little, and in these conditions I may well increase the backstay just to get a bitmore twist in the mainsail and get the top tell tail to fly.
If you let the mainsail twist nicely by nothaving a lot of mainsheet tension, the result is not enough jib luff tension which lets it sag and becometoo full, thus not point. The act of pulling the jib harder simply increases the sag and makes thingsworse.In stronger winds force 4 upwards simply pull on the mainsheet as hard as you can, and only use thetraveller to balance the boat.
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