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2018 AOTY/DOTY Entry

Topic: Hobie AI furling spinnaker  (Read 880 times)

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NowhereMan

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I got Hobie's AI spinnaker sail a while back. It's a lot of fun and can give a very nice speed boost when going (generally) downwind in light-to-moderate conditions. But, it seemed totally impractical for fishing: It sits in a snuffer bag between the aka bars in perfect position to snag, there are lines running everywhere, you can't fold the ama, etc., etc. It also takes a while to rig as there is about a quarter mile of rope that must be strung every which way---even after half a dozen times, I still usually got it wrong on the first attempt.

For a while now, I've been working on converting it to a furling spinnaker and just finished this morning. I think my setup solves all of the problems noted above: It's completely out of the way when fishing and yet easy to furl and unfurl. It's also much easier to set up, and should only add a couple minutes to the overall time.

I made the furler (closeup in the second picture) out of scraps of starboard plastic, nylon spacers, and standard stainless hardware. It's a continuous furler, and I spliced the rope so that it can spin freely (and forever) in either direction. It seems to work extremely well.

The stuff for the furler cost less than $20 and the rope was a little over $20. I used an expensive ($30+) Ronstan ball bearing swivel on top, although there are a lot of cheaper options for that. There are also a few shackles and such (although rope probably would have worked fine). I'd say the total cost of the materials was certainly less than $100.

I did get the sail modified, with a pair of thick spectra lines installed. Supposedly that does a better job of transmitting torque to the top, but I don't think it makes a huge difference (the stock spinnaker would definitely furl with this setup, you'd just tend to have more twist in the sail).

I'll post more once I get a chance to test it while fishing.
I got blisters on my fingers!


sebast

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Looks good!

On somewhat related topic: I remember seeing pictures of 2nd sail furling onto the main mast - just wonder if you ever considered such setup.
OK Ultra 4.7 (yellow)


NowhereMan

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Looks good!

On somewhat related topic: I remember seeing pictures of 2nd sail furling onto the main mast - just wonder if you ever considered such setup.

People do that with jibs. For the spinnaker it wouldn't make sense to have it open whenever the main sail is unfurled, as it's just for downwind. So it really does need to operate independently.
I got blisters on my fingers!


sebast

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Looks good!

On somewhat related topic: I remember seeing pictures of 2nd sail furling onto the main mast - just wonder if you ever considered such setup.

People do that with jibs. For the spinnaker it wouldn't make sense to have it open whenever the main sail is unfurled, as it's just for downwind. So it really does need to operate independently.

Yes, exactly -  was just wondering it might be easier to implement and manage. Of course, jib is not spinnaker :)
OK Ultra 4.7 (yellow)


NowhereMan

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Here's a short video of the sail in action. Very light winds, but I think it'll work equally well in more demanding conditions.

I got blisters on my fingers!


mateo

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nice set up....what kind of speed difference do you see with the spinnaker?  Do you think it possible to fly a non asymmetrical spinnaker?  Wondering if the difference in knots is worth it??  Thanks


NowhereMan

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nice set up....what kind of speed difference do you see with the spinnaker?  Do you think it possible to fly a non asymmetrical spinnaker?  Wondering if the difference in knots is worth it??  Thanks

I haven't tested it carefully under good conditions yet, but there are some videos online where people show 1.5 to 2 mph improvement. Another side benefit of it is that the spinnaker tends to lift up the front, making the boat glide over the waves instead of nose-dive thru them all.
I got blisters on my fingers!


mateo

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nice set up....what kind of speed difference do you see with the spinnaker?  Do you think it possible to fly a non asymmetrical spinnaker?  Wondering if the difference in knots is worth it??  Thanks

I haven't tested it carefully under good conditions yet, but there are some videos online where people show 1.5 to 2 mph improvement. Another side benefit of it is that the spinnaker tends to lift up the front, making the boat glide over the waves instead of nose-dive thru them all.
Ok cool!  I do not yet own a TI but when I do I will trick it out like crazy!



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NowhereMan

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  • Location: Los Gatos Mountains
  • Date Registered: Aug 2011
  • Posts: 4859
nice set up....what kind of speed difference do you see with the spinnaker?  Do you think it possible to fly a non asymmetrical spinnaker?  Wondering if the difference in knots is worth it??  Thanks

I haven't tested it carefully under good conditions yet, but there are some videos online where people show 1.5 to 2 mph improvement. Another side benefit of it is that the spinnaker tends to lift up the front, making the boat glide over the waves instead of nose-dive thru them all.
Ok cool!  I do not yet own a TI but when I do I will trick it out like crazy!

Ha ha! Yes, that's part of the fun of owning one...
I got blisters on my fingers!


NowhereMan

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OK, here's a little more info on this after having used it more.

It furls well in light conditions, as shown in the video. But in more challenging conditions, it can be difficult to get it to furl---it tends to get a "windsock" at the top, which is really annoying (at best) and could even be a hazard (at worst). It can be furled, but it usually takes me several tries to get it done right when the wind picks up. I talked to one guy on the Hobie group who had tried something very similar to my setup and he had the same problem. He ended up using a PVC mast and furling around that, but I want something that's easier than that to set up, and is easy to take down on the water if need be.

So, I'm now looking at alternatives, and I think I've got something that will do the trick. I'll post the details once I get a chance to test it out...
I got blisters on my fingers!


Fuzzy Tom

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   More of a genoa sail (attached to the forestay,or very tight along the luff (front edge), than a gennaker(not attached or real tight  to the forestay, only at the tack (lower front corner ) and at the head and asymetrical? 
   I suppose that with the speed of a multihull cat or tri the apparent wind (the angle of the wind when you are moving ) allows you to use it when going almost dead downwind to the actual wind?   
    Wind socks or hourglasses in a spinnaker can sometimes be really nasty to undo even when you can stand under them - and could cause a capsize.  Have you tried rounding up into the wind before furling it?
 


NowhereMan

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   More of a genoa sail (attached to the forestay,or very tight along the luff (front edge), than a gennaker(not attached or real tight  to the forestay, only at the tack (lower front corner ) and at the head and asymetrical? 
   I suppose that with the speed of a multihull cat or tri the apparent wind (the angle of the wind when you are moving ) allows you to use it when going almost dead downwind to the actual wind?   
    Wind socks or hourglasses in a spinnaker can sometimes be really nasty to undo even when you can stand under them - and could cause a capsize.  Have you tried rounding up into the wind before furling it?

I don't know that much about sails, but there has been a some discussion on the Hobie forum as to exactly what kind of sail this really is. It's designed for (generally) downwind sailing, as that seems to be a weak point of the AI. It's symmetrical and works OK with the snuffer bag as designed (although it is easy to run over the sail if you're not quick), but not at all practical for fishing, IMHO. I tried lots of things to get it to furl, and could get a good tight spiral once in a while, but it was unpredictable, and a major a hassle. And, you are correct that it could be hazardous, as I had to quickly drop the sail once (on Lexington) when the wind started gusting and it would not furl properly. People on the Hobie forum who have experimented with this sort of thing have had similar experiences---they all seem to have given up.

I recently got a bargain in a torque rope, which should act essentially like a flexible mast (so it can be raised and lowered on the water, if need be, which I consider necessary for safety). I'm pretty confident that this will eventually work---I should be able to test it out this new (and improved!) version fairly soon, and will post something then...
I got blisters on my fingers!


Scurvy

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On many monohulls I've seen while sailing, mind you I have NOT been on a boat when a spinnaker was in use, IIRC the spinnies all seem to be deployed and replaced directly from its sail bag.  In fact, I've seen self-furling setups and those were NOT the torque kind normally used for jibs (too much belly fabric creates the problems you describe), instead, they are automated stuff sacks.

The head of the spinnie gets run up and down the forestay or a similar line connected to the top of the mast, which passes through the stuff sack, so it looks like the sail's head and clew get released but remain under tension to help the sail get pulled back into the sack in an organized fashion. The key here is that the foot of the sail is captured first, and the capture moves progressively to the sail's head, which allows the air to escape; deployment is the opposite and as the top is pulled out of the bag in a controlled and under-tension manner, the sail is able to fill and deploy in a controlled manner too.

Make sense?


NowhereMan

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Make sense?

I think so, but I don't have a bunch of different sails, so the plan is to have it already out of the "bag" and furled, ready to deploy when I launch.

The top down furling I'm thinking of is kind of like this, but of course on a smaller scale...

I got blisters on my fingers!


Scurvy

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Make sense?

I think so, but I don't have a bunch of different sails, so the plan is to have it already out of the "bag" and furled, ready to deploy when I launch.

The top down furling I'm thinking of is kind of like this, but of course on a smaller scale...

Well the idea with a sail bag is that the sail gets stored in it if it's not in use, and it very quickly gets stuffed inside. It's a hasty stuffing exercise, not a slow winding process, and won't leave big inflated bubbles to screw things up.


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