Self-Tacking Jib for AI

I measured the sail today. The ruff dimensions of the jib are as follows...
Luff 133 in.
Leech 117 in.
Foot 51 in.
This results in 23.54 sq ft of jib

I called Banks Sails in Kemah about making the sails. The cost for the sail is only $380 and they ship anywhere including Australia. This is not you average jib. It is a miter cut and Code 0 material. The mitered cut is more difficult to make but provides for the great shape it has and the Code 0 material is a new, strong, lightweight material. This lightweight material feels very thin and allows you to bunch up the jib and stick it in a small bag or under the hatch bungees while sailing. The material has minimal if any stretch to it so it maintains the desired shape when sailing, no matter what winds you are up against. I will try to post a picture later showing the mitered cut. Here is the sail maker's contact information.

Banks Sails Gulf Coast
Address: 1207 Marina Bay Dr, Kemah, TX 77565
Phone:(281) 334-7223
bankssailstx.com

I will put together a final video that shows the hardware needed and how to put it all together. There is nothing to it.

About submarining. I do feel that there is more water over the bow but not really submarining. Not really been a problem. I have TI amas on an 2012 AI hull which may give me an advantage, preventing submarining. It certainly adds stability as the 2015 AI owners can tell you. I can try it with my original AI amas if anyone wants to know.

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Greg

2016 AI - Spinn & Jib

“Out of sight of land the sailor feels safe. It is the beach that worries him.”
– Charles G. Davis

Stringy, please clarify. Both sails working together makes furling and unfurling a bit more difficult but still very do-able. I typically, do not need to use my hand on the mast but do need to give the main a little pull. Can you give me more details and what you have in mind? I would love to gain some mechanical advantages with the furling/unfurling process. The problem is small and may not warrant new lines. The one line that is on the port side is the furling line attached to the tack of the jib. Pulling it helps the unfurling process because the mainsheet pulls the main and the jib tack sheet pulls the jib open. Furling is the bigger chore as on line pulls both sails when furling.

I have not given up on the concept on no additional lines in the cockpit. Down to only one additional line at this point - shooting for none.

Vetgam

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Greg

2016 AI - Spinn & Jib

“Out of sight of land the sailor feels safe. It is the beach that worries him.”
– Charles G. Davis

Vetgam,
I use an unfurling line on my small sail mast adaptor when using my AI in Adventure kayak only mode. It allows me to micro adjust the small sail easily when the wind picks up. No more hit and miss with how much sail comes out by tugging on the mainsheet.

It's just a knotted line dropped through a hole in the top of the furler drum and wrapped the opposite way around the drum, exiting the port side. I'm trying to remember but I'm pretty sure I got the idea from Roger Mann's original jib video.

As Bob sez, the jib should add some lift sailing upwind and improve pointing/tacking. Cutting through the waves will improve.

On a broad reach in big wind, it could drive the bow down or sink even the bigger Amas. You might even break pin or brace.

But wheres the fun if you don't try?

I'd like to see the mast top/halyard setup.

Thanks VG.

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The Wind Is Your Friend...

A broad reach is not causing bow diving for me unless I sailing in winds above 17 mph or so. Then I just take to jib down or sail 1/2 furled. Not really an issue.

I will show the mast setup and in a final video. The halyard is not a typical halyard. I was able to remove 1/2 of the halyard line by using a counterweight on one end. Hard to describe, but I will show it in the final video. This eliminates having to coil the halyard line when the jib has been raised. One less line to deal with. When the jib is up, I unclip the halyard and the jib head lowers only when I pull it down. If I lift up the jib, the counterweight drops and the jib raises up. Once you get the weight right, it works very smooth.

Vetgam

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Greg

2016 AI - Spinn & Jib

“Out of sight of land the sailor feels safe. It is the beach that worries him.”
– Charles G. Davis

Great work! After 4 years of being in love with my AI, I traded up for a new 2015 TI about a month ago and I've been contemplating adding a jib. Fortunately for me the business beside where I work makes sails, so hopefully I can take the great knowledge and work seen here and present it to them. Now if I can only get them to use the same materials hobie uses to make it look as sexy as my photoshop mockups... Maybe if we make enough chatter someone at Hobie might take notice, seems like they've been flirting with the idea of an addon jib for as long as they've sold these boats. Regardless I plan on adding one after a little more prep. and planning work.

I like your design. Especially the second fractional sail.

My experience with the AI jib taught me a couple of things that you'll want to keep in mind. If I could do it all over again, I would reduce, not increase the size of my jib. i think too big a jib limits the range of winds ideal for using it. In the case of a TI you have a proportionally smaller bow. My sugestion is to keep it no bigger than an AI jib and keep it fractional.

The other sugestion is to use lighter weight materials than your main. This will make it easier to raise, lower and fold the jib. There are times when the wind suddenly picks up that you will want the jib down, not just furled. This gives you the control you need if things get dicey.

Vetgam

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Greg

2016 AI - Spinn & Jib

“Out of sight of land the sailor feels safe. It is the beach that worries him.”
– Charles G. Davis

One more thing about the TI. Make sure your 2015 design does not have the same issue as past TI's with front hatch leaking due to flexing when you lift the bow by the front handle. If it does, I would be concerned that you may find that you start taking on water. The jib tension mimics lifting the bow.

Vetgam

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Greg

2016 AI - Spinn & Jib

“Out of sight of land the sailor feels safe. It is the beach that worries him.”
– Charles G. Davis

I'm pretty sure a TI would be fine with the exact same sail (20-25 sq ft) with no structural mods neccessary. I have made and tried many jibs on my TI's, with the biggest being around 40 sq ft, I ended cutting them all down smaller because of weather helm and various other issues (like the bow waving around and the hatch leaking like a siv with the bigger jibs and spins). I feel with really large fore sails like my 135sq ft spin plus a 30sq ft plus jib you are at great risk of folding the bow without external hull re-enforcement bracing.
Another problem that creeps up when upping the performance of the TI speedwise with massive sailplans and big ole outboards is in normal offshore chop the hull and AMA system takes a tremendous pounding (so do the passengers (lol)), and needs additional external bracing and hardening in my opinion. I'm pretty certain I'm way beyond any of Hobies original design spec's but I now feel I have the most awesome boat on the planet (lol).
Bob

We have all scoped many Foresail mods over the years, this promising innovation looks the most refined and simple in component and installation so far.

Correctly it flies with a tad lower angle of attack than the main, if you watch the video the main loses lift before the Jib does when it goes about which proves its working.

Last, I don't mind lots of ropes to play with, The V-Sail, Barber Hauler etc give me Six already.

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Fair Skies, Max.

This is a great thread - thanks!

Hey Bob, would a similar self-tacking setup work with your wing?

Bobagain:
Actually I think a self tacking traveler thingy would be awesome on my wing jib with the only downside being the sail may no longer freely weathervane 360 degrees when not engaged. With the current single string if I let the string go, the wing harmlessly weathervanes 360 degrees in a symmetric form with nearly zero drag (thats just the way all wings work).
As you saw when we were out, wing sails are the strangest thing ever, it's hard to wrap your mind around everything since you are nearly always traveling faster than the natural wind speed (sometimes 2x-3x faster) it just changes everything. Also as you saw that tiny 33sq ft wing sail can be more powerful than my main, so when winds pick up I tend to put the main away and just use the wing (safer since you can't possibly capsize via the wing since it only creates a tiny sideforce.
Bob

Have'nt seen it.

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Fair Skies, Max.

The wing?

https://www.youtube.com/watch?v=0AhpTmPI2as

Aha thank you, cant wait to see you're next design.

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Fair Skies, Max.