Showing posts with label sailmaking. Show all posts
Showing posts with label sailmaking. Show all posts

Sunday, April 7, 2013

Third reef sailing report

After our spring cruise in the Core Sound last year, I decided to sew a third reef into our sail.  I finished the improvements in the fall but didn't get to test it out until our 2013 spring cruise last week at Smith Island in the Chesapeake bay.  I had been unsure whether the third reef would be worth the effort and now I have answers to my questions.
Tied up after an afternoon sail

The third reef was awesome!  

It was sunny, cold and windy, with northerly winds from 15 kt to 25 kt, sometimes gusting to 30 kt and daytime temperatures in the 40's.  We were able to comfortably sail upwind with no gymnastics on the windward rail.  The new mainsheet also worked out well and while my hands are a bit raw from working in the cold, the cam cleats and heavy nap of the rope were a joy to use.  We met a few watermen while staying on Smith Island (more about that later) who were surprised to hear that we were going out in such weather.

Q: Too little sail?
A: It was just right.  We were able to tack upwind during the worst of the gusts.  The forecast during the first test of the third reef was 15kt to 20 kt gusting to 25.  Our average hull speed was 3 mph with bursts to 3.5.  Creamcheese's best upwind speed is a little over 4 mph.  I estimate she pointed about 50 to 55 degrees off the wind.  Her best upwind performance is 45 degrees, but she is always faster at 50 degrees.

Sailing upwind
(taken during a lull)
Q: Lee helm?
A: Happily, there was no upwind lee helm but instead the perfect amount of weather helm - about the same as with the full mainsail.  I don't understand how moving the centroid of the sail 19" forward can have no effect but I listed my hopeful explanations in my original post about sail math.  Another possibility is that even though the sail centroid moves forward, the center of effort is very close to the mainmast and so doesn't move very far.  And because the sail lacing gets slack (see picture), the luff of the sail is actually about four inches from the mainmast, thus moving the center of effort four inches aft.




First sail with three reefs tied in (taken during a lull)

Saturday, September 15, 2012

How to Install a Sailrite Jiffy Grommet

New jiffy grommet, old sail

Before installing the jiffy grommets on my clew and tack reef patches I looked for online tutorials or technical notes but didn't find much, so I'm posting my experience here.

When I got my jiffy grommet kit, there were no instructions other than what is printed on sairite's website "... Special tools are not required - simply use a hammer to mushroom the ends of the soft aluminum rivets in place ..."  After some experimentation, here's the process I decided to use.

I had to push the six rivets through seven layers of 4oz dacron.  I experimented on a test patch with a 1/8" drill, but I found that a 1/8" hole punch was far superior.

1/8" hole punch
After punching the holes, I assembled the grommet.

Rivets 
That jagged circle you see in the luff tape is where an old spur grommet used to be before the reef patch was sewn in place.

Rivets ready to be hammered down
Once I hammered down the rivet, used a soldering iron with a flattened soldering tip to cut the hole through seven layers of fabric.  This was quick and easy and had the added benefit of welding all seven layers together for added strength.

Cutting out the fabric - flattened soldering iron tip on right

Jiffy grommet, sail, tools

Third Reef Pictures

Here's a look at the third reef under sail.  I haven't been out in wind strong enough to know whether there will be significant lee helm.



Pretty Day at Marsh Creek Lake
Sharpie spritsail and clouds 

Sunday, September 9, 2012

Sewing a third reef

I decided to make a third reef for Cream Cheese in May.  It has been 12 years since I sewed the sail, and I wasn't looking forward to re-learning all of the special sail sewing techniques. 

Pretty stitches on the new clew reef patch
As it turned out, it was a fun project.  The first step was to pull out my copy of "Sailmaker's Apprentice," by Emiliano Marino, and re-read a few relevant chapters.  Then I ordered the cloth and jiffy grommets from Sailrite.

Next, I spread the sail out on the floor to plan the location and size the various panels that would be sewn together to make the reef patches.

Reef plan
 I did this by taking off the dimensions from the existing patches.

Reef patch dimensions
At this point I was ready to cut the panels.  My reading indicated that scissors aren't the best for cutting dacron sail material because the cut is more likely to fray under heavy use.  A hot knife is the preferred method, but I wasn't going to fork out $400 for an industrial hot knife.  I settled for attaching a rope cutting blade to my soldering iron (with a little modification).  The edges were a little rough, but it was good enough.

Cutting out dacron panels
I had to redo all of the cringle patches because I got the weave orientation wrong (see "Sailmaker's Apprentice").  Each reef cringle patch is 4" square.  There are two patches for each reef patch and the fabric weave should match the weave of the sail at the point of attachment.

I used basting tape to assemble the clew, tack and cringle patches and then put them aside.

Now I was ready to start sewing, but before I could do that, I needed to freshen up on my sewing skills and make sure the needle, thread and machine were going to be able to go through seven layers of dacron.  This probably took more time than any other part of of the project.  My sewing machine is a Janome 7330, which is a "home decor" machine.  It comes with a two kinds of zig-zag stitches, has a pretty good motor and a fairly strong feeder.  I discovered that this machine with a #90 needle will do a zigzag seam on five layers of 4oz dacron, but not on seven layers.  It works fine with a #110 needle but but I was worried that the holes in the fabric were a little too large.  After talking it over with a few people, I decided to go with the #110 needle and larger holes.  I've been happy with the results.

Janome 7330, basted reef patches, practice patch.
Now I was ready to sew!  This part of the operation went relatively quickly.  First, I cut loose the luff tape (seam along the luff of the sail) and pinned the pre-assembled reef patch to the sail.  Then I rolled up the excess material and started sewing.


First seams going together.
Once the tack and clew patches were sewn on, I pinned and sewed each reef patch.

Reef cringle patch
Now that all patches were on the sail, the last step was to install grommets.  The reef grommets were the easiest.  Simply, cut the hole with a 3/8" hole punch and install the #2 grommet with the two part die set.

Reef cringle patch and tools
Installing the sailrite jiffy grommets on the clew and tack were a bit trickier.  A jiffy grommet is comprised of two washers that are attached to the sail using six aluminum rivets.  The kit came with no instructions and there is very little on the web about the best way to do it, but I'm pleased with the results.  

Third reef  - project complete
Now the third reef is finished - I can hardly wait to try it out in heavy weather.