Problem with Z-Spars Furling Main (pics)

[mcaswell]

The in-mast furling main on our Hunter 310 that we bought about 6 months ago has never worked well for us. It would take great effort to get the sail unfurled... I'd have to put the outhaul on a winch, and the sail would reluctantly come out bit by bit in abrupt steps.

Today I decided to tackle this problem. I dropped and removed the main, rinsed/lubricated the bearings on the lower (drum) portion and on the upper (halyard swivel), and then changed out the furling line. After all this, I was thrilled to find the furling/unfurling action buttery smooth... simply pulling the outhaul by hand will unfurl the sail now.

Unfortunately, something is not right. Once the sail is furled, something happens to the upper few feet of the leech. While unfurling, the upper part of the sail sometimes gets badly crumpled/jammed in the slot. I can work most this out by furling/unfurling a few times, but it doesn't fully solve the problem, as these pics illustrate...

Basically, the upper foot or so of the leech (specifically the nylon webbing reinforcement strip on the leech) gets caught up in the slot, and will not come out. I can still furl the sail, but I have to drop the main and pry this section out. I hoist the main again, and the same thing happens as soon as it's furled back in.

I know that vang / mainsheet tension, and possibly halyard tension can affect how well the sail is furled, which manifests itself as a problem when unfurling, so I tried a few variations of adjusting these lines (dropping the main first each time to clear the jam), but the problem reoccurred each time. I ran out of daylight and had to call it a day, but I'm going to go back to the boat in a few days to try again (obviously), and was hoping that perhaps someone here might recognize this condition from the pics and offer a solution.

I'm really at a loss trying to figure out what I could have done wrong with putting the main back on the furler... it doesn't seem like there's much that COULD go wrong. Yet, the fact still remains that I've never had this problem before, but now it happens every time, so it has to be something I did wrong.

--Michael

 

[Steve Dion]

Michael:

I suggest that you get a sailmaker or rigger to take a look at your problem. We took a Gibsea out that had a similar problem. It turned out that the sail was stretched. The club where we rented the boat replaced the sail and it corrected the problem. I would think that some surgery may also correct the problem. Worst case is a new sail!

I would have a pro look at it for you.

 

[John]

Is it possible that you are putting either too much or not enough tension on the out-haul line as you furl the main?

I had a similar problem furling and unfurling my main (different manufacturer, though). The problem turned out to be that the "main in" line was old and had swelled up (probably from salt) and was rubbing on the cage inside the furler, creating a great deal of friction. If your problem previously was the same but caused by swelling of the "main out" line, then this line would have been creating a great deal of tension as the sail was furled. Now, if you've replaced this line, there wouldn't be any tension at all, unless you maintain tension.

 

[jerry]

Furler problems

I have a Charleston spar in mast furler. If the boom aft end is either too high or low, or there is slack on the halyard it could cause the sail to wrinkle when furling. To illustrate, take a square tissue or cloth and fold it into a triangle. Then pull up/down on the corners and see what happens to the luff and picture what would happen as you roll it up. As posted earlier, it could be an overstreached sail. Also, make sure the attachment at the top of the sail is oriented correctly. Hope this helps.

jerry

 

[mcaswell]

Thanks for the responses. I'm hopeful that the problem is not with the sail. Again, this has not happened before... only after I took the sail down and put it back up. So, this leads me to believe I must have done something wrong. Or, as was mentioned, perhaps the new lack of "stiffness" in the system is something I need to get used to... it's quite possible that I did not have enough outhaul tension.

I'll pull it down again in a few days, make certain that the head attachment looks correct, and be extra careful when furling it.

--Michael

 

[BBC16385]

Any chance when you installed the new furling line you rolled it on the wrong way and now the sail is turning in the opposite direction to furl than previoulsy? It would make a difference if that were the case.

 

[mcaswell]

Any chance when you installed the new furling line you rolled it on the wrong way and now the sail is turning in the opposite direction to furl than previoulsy? It would make a difference if that were the case.

Hmmm... yes, that would certainly explain it. I'm trying to visualize the mechanism... it's like a large "screw" that the line winds up on, starting from the bottom, and I'm pretty sure that limits it to turning in the correct direction only (the line wouldn't wind up into the mechanism if it were turning in the wrong direction).

--Michael

 

[CarlN]

Try keeping more tension on the furler as you unfurl. You used to need a winch to pull out the sail. Now it may turn so easily that the bottom of the sail turns the furler "too far" making the top of the sail fold back on itself inside the furler.

Agree on double checking that you furled the right direction. Easy mistake. These masts are meant to furl one direction (if I remember, furl so sail wraps on the starboard side of the furler.)

I realize you didn't change the rig, but do sight up your mast and see how much it curves forward in the middle (called prebend). Hunters need some prebend because they don't have a backstay but too much prebend causes the furler to bind in the mast tube. Oddly, this can cause exactly what you're seeing at the top of the sail. Try to compare your prebend with other Hunters near you. If you have a lot more, find a rigger who knows what they're doing and get the mast as straight as possible.

Carl

 

[BBC16385]

OK, another idea. Try releasing the tension string in the leech. Let it go totally loose. See if that makes a difference.

 

[mcaswell]

Also, make sure the attachment at the top of the sail is oriented correctly.

We have a winner!

I do think that not keeping enough tension on the outhaul as I furled the sail was a factor... that's the first thing I tried, and I was able to furl/unfurl successfully once or twice, but the jams returned.

I took the sail down again and examined how the head was attached to the furler's shackle. It looked right, but I decided to take it off and give the nylon loop a half turn, which looked strange at first, but once the sail was put back in place in the track, it looked "more right" than before. I think the improper orientation of the loop was causing the leach to curl in a bit at the top.

After this, I furled/unfurled a dozen or so times with no problems.

--Michael

 

[sand sailor]

hurray

 

[mcaswell]

I realize you didn't change the rig, but do sight up your mast and see how much it curves forward in the middle (called prebend). Hunters need some prebend because they don't have a backstay but too much prebend causes the furler to bind in the mast tube. Oddly, this can cause exactly what you're seeing at the top of the sail. Try to compare your prebend with other Hunters near you. If you have a lot more, find a rigger who knows what they're doing and get the mast as straight as possible.

Carl,

Using a halyard, I estimated that my bend is about 3.5". I believe the H310 manual recommends 5" (presumably this applies only to the standard mast model)... do you think 3.5" is appropriate, or should I seek to have some of the bend removed?

--Michael

 

[CarlN]

Michael,

It's working now. When it comes to boats, this is both rare and wonderful. Don't mess with it.

Seriously, that measurement sounds fine but it never hurts to have a good rigger take a look at your rig. A few hundred dollars could add a knot to your speed (I've seen this happen after a rig tuning) not to mention keeping the mast from falling down unexpectedly.

Carl