Tuesday, 29 September 2015

dinghy cruising: Reefing my mainsail

I'm not getting it right am I? A quick view of my last video ( see the post below ) proves that.
So let's go through it and if anyone can spot what is going wrong, please help me. Please, please help me!

  1. I have a sprit boom on a sort of standing lug Gunter rig arrangement...kind of......
  2. I have two reefing rows in the main sail
  3. At the aft end of the sprit boom is a sort of slab reefing arrangement. I can pull each line and it collapses the aft lower end of the sail leech. At the forward luff end, I can detach the downhaul and clip it on higher up the luff at the first or second reefing row. I pull the reefing lines from half way along the sprit boom
So, procedurally, I 

  1. Heave too
  2. Then I pull the topping lift up slightly and lower the top yard
  3. The downhaul is switched to the upper reefing row at the luff edge
  4. The slab reef line is pulled collapsing the rear of the sail
  5. The loose sail is brailled up and tied using reefing lines 
  6. Then I pull up the main halyard hauling up the top yard and the topping lift is released
Questions:
How high up should I pull the upper yard....all the way back to mast head........or lower?
How much tension should I put back on the downhaul?


And finally one more quest for help. When sailing under just jib and mizzen, I go to tack and Arwen stalls........every time........anyone know why? 

As always, all help is gratefully received

Steve

8 comments:

  1. Do you back the jib to pull you through the wind when just using jib and mizzen? That is leave the jib sheeted in until the bow is through the eye of the wind before sheeting in on the new tack.

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  2. I'm looking at 1:42 into the video at the moment. Your boom looks too far aft to me, and that's causing the leech to be too tight, which is preventing the yard from going vertical. Try this for Step 6: Loosen the snotter and allow the boom to move forward, raise the sail, tighten the downhaul TIGHT, then tighten the snotter to move the boom aft until the sail sets nicely with no creases. I think doing it in that order will loosen the leech and allow the yard to set more vertical. I see a bit of yard hanging down below the throat. The throat should be lashed to the bottom end of the yard. It looks like your halyard is tied to your yard at about the right place - about 1/3 of the way up. But there should be a loop with parrel beads on it where the halyard ties to the yard that goes around the mast to hold the yard close to the mast. There should be another loop with parrel beads at the tack, going around the mast to hold the tack close to the mast.

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  3. Tacking under Jib and Mizzen is all about speed. Fall off a bit, get the boat moving as fast as you can, wait for a puff, then throw the tiller all the way hard over and keep it there. Next, you have to be fast tacking the jib. The moment she's come about, quickly sheet in the leeward jibsheet tight. Then let loose the windward sheet. That'll back the jib momentarily which will help bring the bow around. If she looks like she;s gonna stall, quickly ease the mizzen. If she does stall, throw the tiller hard over the other direction, grab the mizzen boom and pull it in, and sail backwards to bring her around.

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  4. Ha - you boys!
    Experience counts - thanks guys - that all makes sense. Actually Joel I have the parrel beads - they were attached at top but came loose for some reason but you can see them; down at the tack the beads are there but I must have forgotten to put them on.

    Now I fully understand the snotter and boom bit - it has always slightly baffled me. I have just realised I always have it too tight - so from now on - its raise the sail; tension the downhaul and then set the snotter - I think I do it before the downhaul - no wonder the crease gets in the sail

    Homer Simpson has nothing on me - dur!

    Now I guess you then pull the sail back up to the vertical with the yard hauled up as close to top of mast as possible? Even when reefed?

    With regard to jib and mizzen - I do back the jib - always as a matter of habit actually when tacking - so I guess it must be the mizzen. Its a neat trick using the mizzen to sail backwards - I had forgotten I could do that - I have done in the past to get out of a crowded pontoon mooring - huh - should have remembered that trick!!

    Paul, Joel, as always deeply appreciate the time and help
    its a complicated old thing this sailing malarkey!
    Steve

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  5. Steve, Not sure if this is a double post - if so this is better than the first one. When reefed do not pull the yard up to the normal mast-head position. The point is that reefing both reduces sail area and lowers the sail on the mast, thereby reducing power and reducing the healing moment.
    Clew-to-Throat Sail Creases. IMHO your problem is that you do not use a parrel at the sail tack. The sail has 4 corners, you have 3 of these fixed to spars and the 4th. one is free to float around in a fore-aft direction. (even though it is tensioned vertically by the downhaul, you do not have it controlled fore/aft). You cannot control the tensions through the sail fabric properly. In your video the upper triangle of the sail is okay, but the lower triangle, below the crease, is rubbish. Imagine what the sail will try to do if you could pull the tack forward to the mast - the fabric tension in the lower triangle will increase and try to pull that crease out. When you tension the snotter the boom pushes the clew out away from the mast. Normally this would increase the foot tension of the sail, but because you do not have a fixing mechanism for the tack to the mast, the tack itself is pushed aft from the mast by the boom as well. You therefore cannot generate the desired tension in the foot, and the nasty clew/throat crease appears because that area of the sail is tensioning-up before the foot does. It all turns to custard (old sailing term!) because you are effectively trying to change the shape that the sailmaker built. It took me a while to realise that using too much tension anywhere on the sail will distort the sail. For example, my initial impression was that the more I tensioned the downhaul the more vertical the yard would go. But the shape of the sail is fixed, it determines the angle of the yard to the mast luff. If the tack is located correctly near the aft face of the mast, increasing the downhaul tension will raise the yard until the sail attains its built shape. Further tensioning, which I have been guilty of, only distorts the sail, and then I have tried to vary snotter tension and boom angles to get rid of the resulting mess. John has frequently said a lot of downhaul tension is needed, and this is correct to a point. In my case I have tended to over-do it. A give-away of too much downhaul tension is that I would get a "tension crease" parallel-to and just below the yard. The sailmaker has told me to go easy on the tensions - these sails are not the same as triangular sails - more subtle and more tuning options.
    Cheers, Alan.

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  6. Steve:

    A couple of thoughts on reefing as well as jib and jigger:

    When reefing:

    -Turn head to wind and heave to (if you have sea room, you can sheet the mizzen tight and furl the jib; this will leave you doing about a knot backwards in a decent breeze)
    -Ease the snotter
    -Ease the downhaul
    -Lower the halyard by about the same amount as your reef (if the distance between your normal tack grommet and the tack grommet for your reefing point is 50 cm, lower your halyard by 60-70 cm)
    -Move your downhaul from the normal tack grommet to the reefed tack grommet
    -Re-hoist the halyard until the tack is at the same elevation as normal
    -Re-tension the downhaul (get this one good and tight)
    -Use your slab reefing line to pull the aft end of the boom to the clew grommet for your desired reef
    -Re-tension the snotter
    -Tie in the reefing nettles if you have time to tidy up the foot of the reefed sail
    -Unfurl the jib, bear off until the sails fill, and have fun

    This probably took longer to write than to do. The key points are that the foot of the reefed sail should be at the normal elevation. The head of the sail should be lower on the mast. Also, if you tighten the snotter before the downhaul, it is almost impossible to get rid of the creases.

    Regarding tacking when she doesn't want to come about, try reaching over your head and using the front of the mizzen sprit boom sort of like a second tiller to steer the boat. In other words, if you are going from the starboard tack to the port tack, you will have the tiller hard to port. You would reach up and push the front of the mizzen sprit to port as well. This will let the mizzen help spin you. Finally, do not sheet the mizzen in tight until after you have fallen off onto the new tack. If the jib is free and the mizzen sheeted tight, it will merrily point head to wind and stop. In general, I have found Navigator does not point very well at all on just jib and mizzen.

    I am glad to see you are getting Arwen out. At some point Maria and I need to get Good Enough back out. Things just get so busy...

    Best of luck!
    Wayne

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  7. Steve, the yard will lie lower down the mast when reefed. The tack should always be in the same position. That's what makes the parrel beads on the yard so important.

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  8. Alan, Wayne, Joel
    Thanks guys. Finally I get it. The rig has always puzzled me a little. I learned in lasers, Bahias etc. dealing with three sails and a sprit boom, well I spend most time sailing with a perpetual frown of bewilderment

    Now I get it. It's so clear. THANK YOU!!!

    I'll reread your observations and summarise them for mysel in a post update
    Thanks guys. What a great thing to come home to after a tough school day. It's iceing on the cake.....Wales having just won three out of three games in the World Cup Rugby.

    Steve

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Thanks for taking a look at my blog. All comments and advice are welcome - drop me a few lines. You can always find videos about Arwen at www.youtube.com/c/plymouthwelshboy. Look forward to hearing from you.
Steve