Probably a stupid idea: using a TI sail on an AI

I understand that Hobie probably put a lot of thought into the perfect sail size for the AI, but I'm just curious:
has anyone ever attempted to use a TI sail with an AI? Is that even possible?

I'm guessing that too much sail area equates to poorer handling in strong winds, but what about lighter winds when you can use all the sail area you can get?

Well I didn't think it was such a stupid idea!
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I did give it a good test on this trip, though the winds were anything but light.
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I mostly had it furled to AI size or less (see the mark I made when I overlayed the AI sail) so it wasn't really a benefit. It did sail well though when it was furled so it wasn't a disadvantage either.

Yes, in stronger winds it overpowers the rudder, so it is really only a benefit in winds around 10knots or less. It needs the updated rudder, which I have but haven't fitted yet. I still prefer the twist-n-stow as I use this a lot more as a kayak in my twice weekly commute.
The few times I have tried it in lighter winds it is definitely faster than the standard sail.

Thanks for the report, Stringy. It is definitely the type of upgrade the AI needs plus modifying the hull and amas to handle the larger sail.

Keith

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2015 AI 2, 2014 Tandem

"Any intelligent fool can make things bigger and more complex ... It takes a touch of genius and a lot of courage to move in the opposite direction." A. Einstein

"Less is more" Anon

Very interesting, Stringy. So out of curiosity (outside of buying a TI), where might I get a hold of a TI mast/sail?

And here it is in all its glory. Pretty impressive mod. ( but you know what they say about blokes with big sails ? )

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Don't take life too seriously................it ain't permanent.

Having an option to put on a larger sail for light winds (what we typically have in my area) makes perfect sense. If anyone has tried to sail a stock AI or TI in 5-6 mph winds can attest to, unless you really like cruising at 3mph. On light air days I typically see all the boats out on the water with light air sails (way bigger than normal sails), boats like sunfish, lasers, and day sailers so why not have a bigger sail available for those light air days.
My 2 cents
Bob

"...plus modifying the hull and amas to handle the larger sail." In other words, it would need to be a TI. Sort of.

The real problem with trying to run a TI sail on the AI is the geometry between the larger sail and the shorter hull. The pull on the clew doesn't come from the right angle.

Rather than trying to adapt a TI sail to an AI for light air use, the better route to take might be a specific light air sail that will still fit the AI geometry. Whether or not there is a market for such a thing I have no idea.

Personally, I am definitely NOT thinking of a TI--too large, too heavy, too wide. I'm thinking of an AI upgrade--something with more speed, but still can be handled by a single person on a camping trip where you may have to drag it up 4-8' (vertical) to get above high tide. Maybe something so simple as a TI-size sail that can be furled in heavy weather. Beef up & lengthen the amas. Hobie MUST be working on this--but when will it get to market???

Keith

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2015 AI 2, 2014 Tandem

"Any intelligent fool can make things bigger and more complex ... It takes a touch of genius and a lot of courage to move in the opposite direction." A. Einstein

"Less is more" Anon

Right, but the boat would have to be larger/longer, with more flotation in the amas, which means it's going to be larger, heavier, maybe wider, etc. Maybe something in-between the size of the two, I don't know. I'm sure Hobie has to weigh the demand against the costs to develop such a new craft.

Back to the original question, you can rig the TI sail on the AI but the geometry isn't quite right. And in better wind, you're apt to find that the amas don't have sufficient floatation to prevent capsize unless you hike out on a tramp to windward. I toyed with the idea early on and considered swapping TI amas onto the AI and making some other changes, but in the end didn't follow through on it.

Tom, I don't see why you would have to make the AI wider to carry a larger sail. As Stringy has shown, you can fit a larger sail to the AI, AND he was using the old rudder. That is where a significant modification might have to be made--in the rudder/stern area. I don't know the dynamics of modifying the amas, maybe longer & flatter would be sufficient. I don't see any need to lengthen/widen the AI. Maybe even make the hull more narrow by 1-2 inches. Maybe a little more volume in the bow.

Personally, I want to keep the weight down. To me, increasing the weight (wider/longer) is counterproductive.

Keith

_________________
2015 AI 2, 2014 Tandem

"Any intelligent fool can make things bigger and more complex ... It takes a touch of genius and a lot of courage to move in the opposite direction." A. Einstein

"Less is more" Anon

Thanks for all the input, guys. So my problem right now is that I'm hundreds of miles from the ocean, and my main option is lake sailing where light winds are always an issue. I can car-top my AI, which is great, and I don't want anything bigger. I'm just looking for options for better sailing in light wind without going back to the drawing board and building my own trimaran.

It makes sense that the direction of force on the clew isn't quite right, but in light winds, hopefully that isn't too big of a deal. At this point, I'd like to try it, but I have no idea where to get a TI sail. I'm guessing Hobie charges a premium for such things (as they do pretty much everything).

The only other option I've seen on this forum is some sort of headsail. A jib looks like it could be helpful in light wind, but the added complication of all the extra rigging is a bit daunting, and I only have one AI to ruin.

Or I could just drop it off at fusioneng's place and see what happens. Probably end up with a Canadian arm and docking capability with the International Space Station.

Making the boat smaller, narrower, etc., or even keeping it the same size, while adding more sail area can have certain benefits, but there are serious downsides as well. If you look at the broad market appeal these boats have, one of the reasons is because it's fairly hard to get into trouble with the current sailplan.

An H16 will give you a lot more performance than the AI, but at a price. You're going to have to put a lot of effort into sailing it and take great care not to capsize or pitchpole the boat in certain conditions. It rewards good sailing and punishes bad sailing. And that's more and more true as you climb the ladder toward higher sailing performance.

The one area the Islands suffer in with light wind is really DDW or anything close to it. Have you tried a barber pole set up or something similar? A boomless sail has advantages but suffers downwind beyond a certain point. Something to make the most of what you have can make a big difference in that area. And that might be as simple as a Hobie barber pole accessory, if they feel there's enough demand for it.

I agree with you Bob. Better sailing performance in light winds was the reason I tried this. I have never been interested in adding a jib or anything that increases the complexity for sailing and while I applaud yours and others efforts with jibs etc it just wasn't what I was after. I love the simplicity of a single furling sail and having the larger TI sail at hand I thought it worth trying.
I can see Hobie's problem though with offering a larger sail. Users would be sailing with it unfurled in 30 knots! I have been very carefull to furl it when the wind gets up.
I'm actually happy with the AI's performance, as it is, in all but the lightest of winds. Hiking out negates the need for larger ama and prevents submarining. Haka are the best performance upgrade IMHO and should be an accessory Hobie offer.
Perhaps the best way to get better performance would be to improve the type of sail. A furlable wing sail would be perfect ...but maybe not technically possible?

I think the saddest part is that Hobie could "put all of us out of our misery" by producing a rotomolded haka, but hasn't done so. It could have "scuppers" all over the place to increase its load carrying capacity as well as make it a cinch to bungee it down onto the akas. One size would fit all (as well as both sides), and dare I say that if they didn't want to make different coloured versions, dune is neutral enough so as not to clash with other hull colours. (honest, it is a total coincidence that my TI is dune )

The nearest I can see to the potential product is a spine board (gee, if Hobie designed it right, they "could make a killing" (sorry) in that market as well! Unfortunately the only ones I can find on fleabay include shipping costs to Oz of over $250!

Please Mr. Miller Sir, here is an opportunity for Hobie going begging! These hakas would even retrofit earlier models, widening your market even further.....

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Tony Stott
2012 Tandem Island "SIC EM" with Hobie spinnaker

Hobie HAKAs are a no brainer, Tony. One size fits all. Buy them singly or in pairs. Buy adapters to make them into a table (or double-wide table.) Half of the Hobie AI/TI world would buy them (if they are smart.)

What we really need is an AI upgrade, sooner rather than later. Some enterprising person/company could sneak in here and eat Hobie's lunch.

Keith

_________________
2015 AI 2, 2014 Tandem

"Any intelligent fool can make things bigger and more complex ... It takes a touch of genius and a lot of courage to move in the opposite direction." A. Einstein

"Less is more" Anon