Hobie Island sailing: Jib vs drifter...

If you are into AI sailing, you might be interested in this--or maybe not...

For the past couple of years, I've been using a roller-furling jib most of the time on my Hobie AI, and I've found it useful in certain scenarios. One obvious situation where it helps is in light winds, where the extra sail area can add significant oomph, often making sailing feasible, when it would otherwise be all pedal-power. In moderate winds, the jib will often add a couple mph, which might not sound like much, but it can make things a lot more fun, sailing-wise.

If the wind is strong enough (maybe 8-10 knots or so, depending on conditions), the main is all that's needed, as any more sail area will overpower the boat. However, even in such winds, I'll sometimes use the jib instead of the main (or, the jib plus a partially-to-mostly-reefed main), because it can be more comfortable sailing. For example, going downwind, with trailing seas, the main will tend to cause a nosedive effect, which I find to be extremely unnerving. The way I've got my jib positioned (angled slightly upward from the bowsprit), it tends to provide just enough lift to mitigate that nosediving effect. Wing-on-wing (downwind, with the jib out to one side and main out to the other) is also fun, but challenging to maintain in typical rolling conditions on the ocean.

This past year, I picked up an old industrial sewing machine for free, and I've used it to make a jib and a main. The main is OK, but the jib has been great--much better than the off-the-shelf dinghy jib I was using, and I attribute this mostly to the fact that my DIY jib is made out of lighter cloth. So, now I want to go even lighter with the jib, to see how that will work. I've ordered the supplies to make a so-called "drifter" sail, that is, a jib-like sail (actually, a genoa, which is just a larger jib) that is made out of lightweight nylon. Jibs are typically made of dacron, which is stiff and crispy, and sound like paper or house wrap when flapping in the breeze, whereas nylon is used for spinnakers (those big puffy light wind headsails). If I get it right, the drifter should work even better than the jib in light winds (say, less than 8 knots), it should point into the wind just as well as a jib, and downwind it should be better than a jib. The lighter weight itself is another benefit.

I should have all of the supplies by Friday, and plan to work on it over the weekend, and hoping to have it ready for sea trials by next week...

It will be interesting to see how it works. I’m not a sailor, but like learning about it and hearing your story. I look forward to the photo essay and report.

Sounds like an interesting mod. Please continue to share as you put it together. Does it attach to the AI the same way as the jib?

Does it attach to the AI the same way as the jib?

That's a good question, and I've got a couple of options. My jib furls onto a carbon fiber tube, but I've also got a torque rope that I used previously with a spinnaker. For upwind sailing, the solid carbon fiber approach will almost certainly work better, so I think I'll probably go with that, but might experiment with both...

Very cool.  Good luck and I look forward to hearing about your trials and next steps!  As an AI owner, I have sailed a few times, and the nose diving effect is for sure unsettling.  I dont have the time to dedicate to experimenting with jibs, but I can totally see this becoming a thing once my kids are older.  Thank you for documenting this, and as I mentioned, I am excited to read more and learn vicariously through you for the time being. 
 

I received my order of 0.75oz ripstop nylon, and I think it is too lightweight. But, since I've got it, I'll give it a try, then I plan to duplicate it in 1.5oz nylon.

The first step is now complete, which consisted of cutting out the pieces of cloth. For simplicity, I decided to follow the same design as I used on my previous (4 oz dacron) jib. I find this cutting step to be the most physically taxing part, as it involves lots of crawling around on the floor.

The remaining steps will consist of taping the seams, sewing, adding a couple of grommets, sewing in a ring, etc. Sewing-wise, this nylon should actually be easier to work with than dacron, as it can be folded without concern for it getting creased.

More details to follow...

I had some trouble dialing in my sewing machine for this thin material, but finally got the pieces taped and sewed together. All that remains is to reinforce the corners, do the edging, and install grommets...

I forgot how long it takes to cut, tape, sew, etc. Anyways, it's nearly done, as I just need to install a few grommets and then it'll be ready for sea trials (or, maybe, lake trials).

Now I just need to get on the water and test it...

I finally got a chance to test this "drifter" sail yesterday. It worked well, but I think it puts too much stress on the carbon fiber rod that serves as a mast for my headsail (jib, genoa, drifter, etc.). Action cams make everything look curvy, so it's hard to tell from the video, but at some points of sail, there was too much bend in that mast. I think I can fix that by making the "sleeve" that fits over the the mast out of more rigid material, and I'll test that in version 2...

Cool! You have such nice sailing conditions in Santa Cruz.


Maybe the flexing carbon fiber is fine, like a fishing rod? It handles load cycles well. Or maybe it’s putting too much stress on other components?

Cool! You have such nice sailing conditions in Santa Cruz.


Maybe the flexing carbon fiber is fine, like a fishing rod? It handles load cycles well. Or maybe it’s putting too much stress on other components?

I was surprised that conditions were that good, as little wind was predicted, but it was probably about 8 knots. No whitecaps and little swell meant no bashing thru waves.

The carbon fiber could probably take it, but the sail loses some of it's shape--not too big of a deal, except when trying to point into the wind. Real sailboats generally use a wire (or torque rope) instead of a mast for the jib, and they rely on putting the wire under a lot of tension to maintain the shape of the sail. Due to its flexible windsurfer-like main mast, that's not possible on a Hobie Island, and thus the carbon fiber mini-mast...