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post #14 of Old 08-13-2013
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Re: Help unfurling an in mast furling mainsail on a 2008 Hunter 31

Originally Posted by Jeff_sf1 View Post
Hello Everyone,

I am new to sailing and recently had a terrible time on the water trying to unfurling an in mast furling mainsail on a 2008 Hunter 31 which jammed and I was not able to sail at all that day.

Could someone explain their technique for unfurling and furling the main? or let me know if I am doing something incorrect. The following is the procedure I thought was correct:

1) motor into the wind

2) leave the main sheet stopper closed, leave the main halyard stopper closed, leave the boom vang closed, leave the jib halyard closed.

3) open the outhaul and put one wrap around the winch, next open the furling in and out.

4) keep tension on the furling out line and pull the out haul until the sail is out

5) close the furling in and out, close the outhaul and then open the mainsheet stopper and sail to a close haul in order to unfurl the jib.

Any help, tips or explanation of the procedure would be greatly appreciated.
I apologize that the format for thiswill be a bit off. It was an article I published a while back (sorry, no pics). Hopefully this will help.


In-Mast Furling Mainsails

<Removed C400 specific discussion>

The issue with in-mast jams is that the vast majority of the sailors using the system are not correctly using it. Most of us were never instructed on it or because we are seasoned sailors, use it as we would a traditional main. Therein is the problem and why in-mast often get a bad name. For the record, I have never, not in many thousands of miles, had one single jam. The following steps will help you keep from jamming your in-mast also.

First, look at the picture:
<Insert Pic 1>

Note the location of the clew. It does not go horizontally into the mast. It travels up at an angle into the mast. This is critical to understand. Why? Because as a traditional (slab) reefer, you would point into the wind, tighten down the mainsheets to keep the boom centered, some even tighten down on the boom vang to help, haul up the main halyard until you have reached the top, then fall off and begin adjusting the vang, sheet, outhaul and halyard to the appropriate point of sail and conditions. We effectively reverse these to drop the main, again keeping dead to wind or close to, and keeping the sheets and typically the vang taunt. If you do that on an in-mast, sooner or later you will jam.
On In-mast, you MUST allow room for the car to travel down the boom and for the clew/sail to enter and exit at its proper point. If you cinch down on the main sheet and vang, then begin to haul in the reefing line, you will see that you cause tension down the leech of the sail. This often results in crinkles forming as you reef. These crinkles are what cause jams. So, when reefing your in-mast, you must release the tension on the main sheet and vang. Take the tension off so the sail can roll into the slot as designed. Also, keep some tension on the outhaul as you reef it to prevent any unwanted crinkles and a smooth roll. Lastly, you will notice the mast is slotted more to one side than the other. Depending on where your sail rolls, one point of sail may be easier to reef than others. For us, ours is a starboard tack. This is because the sail rolls out away from the mast and does not rub against it while reefing. Don’t forget to put some McLube on the boom track to reduce the friction on the car. I do this about once a month.
One final point: We almost never use the winch to reef our sail in normal conditions… and NEVER use the electric winch. If you reef the sail by hand, you can feel any potential jams before they happen and can pull them back out. If you gorilla-arm that sail in with the winch or the electric winch, you can create a jam that will be very difficult (if not impossible) to get back out. If you find yourself in a situation where you have to winch in the main, at least go slowly and keep staring up the slot for crinkles going in.
I am a fan of in-mast mains for most sailors. It keeps the crew safe and in the cockpit instead of tidying up sails on deck. It also gets a lot more use then what traditional mains because it is so easy to use and reef. Keep in mind what I said above when operating the sail, and you too should get thousands of trouble free miles.

Brian Mistrot
S/V Sea Mist IV, C400 #289

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