2015 AI: Larger Sails?

I recall posting a question about using a TI mast/sail on an AI and the consensus seemed to be that it works if the anchor point for the mainsheet is moved aft..... but I cannot find the thread - so here goes again....

Seems like a bigger sail - let's say, 7.5 meters (or even the TI's 8.4 if somebody were willing so spring for a new mast) - for the AI would have no downside (since it can be roller furled) and have the upside of better speed in light air.

Ama submarining seems to be a built-in safety limit for mast stress as long as people aren't hiking out on a tramp or haka.

But I don't see any aftermarket sails for AI's..... period.... much less larger ones...

There has to be a reason and, therefore, a flaw in my reasoning.

But what is it?

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2015 AI in "Dune" - "The Grey Pig"
2017 Trailex 450 Trailer
Pre-September 2015 cradles
(anybody want to buy a slightly-used AI SpinKit?)
eMail: [email protected]

Pete, I think it is simple really. The sheet angle is limited by the amount of hull existing back from the mast. Increasing the sail area can therefore realistically only go vertical, instead of being able to increase the length of the foot. Adding sail area via using a longer mast offers relatively little extra performance compared to the increase in heeling moment.

But there is probably an over arching reason for the current specs... Islands have not been created as pure performance machines, instead being quite clearly aimed at versatility. It is also perhaps no coincidence that both Islands have masts which are about the same length as their hulls, making carying/trailing much less of a hassle than that experienced by cat users...

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

Thanks. That is the thread I was thinking about.

What seems to being lost sometimes in some replies is that the larger sail is for light/moderate wind performance - not for top-end speed......i.e. sail area still gets reduced via the roller furl once an ama starts submarining.... it just gets reduced a little sooner.

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2015 AI in "Dune" - "The Grey Pig"
2017 Trailex 450 Trailer
Pre-September 2015 cradles
(anybody want to buy a slightly-used AI SpinKit?)
eMail: [email protected]

Pete:
There might be an unexpected problem with adding a TI sail to an AI. You will no longer be able to enjoy the scenery as you go past it. (Just being funny).

Actually I believe the bracing system below deck for the mast is identical for both the AI and the TI (someone correct me if I'm wrong), as well as the AMA/AKA bracing systems are all identical on both boats, whats good for the goose is good for the gander (lol). Now they have the bow flotation problem solved (the previous AI bow didn't have enough flotation (ie.. It dove too easily). And the old AMA's didn't have quite enough flotation (just a tiny tad too small).

Like the other guys said though the attachement point for the sail control line at the back of the boat might be an issue (it's not far enough back for a larger sail). However you could do like I did and just run a double loop of Spectra (rudder line) around the rudder gudgeon and attach the sail control pulley's to that vs the current position (that buys you a an extra foot or two). I ran a similar setup on my TI for a while (with the spectra on the gudgeon) and it didn't seem to hurt anything, however I did it for different reasons (I got tired of the sail control line at neck level when in the back seat, and was trying to correct that (I since moved it back to it's original attachment point (I gave up trying to sail from the back seat, so I moved the control point back to it's original location because I didn't need it back there any longer since giving up on the back seat, ( I gave up on the back seat because I felt trapped back there (can't hike out from back there to balance the boat out). Keep in mind my TI is pretty heavily modified with way too much sail area (around 260 sq ft of sail area at times (about the same as an H16)), there is no way to sail the boat without using your body weight to balance the boat out ( basically I have to hike out on the tramps just to sail the boat (which is no different from an H16 or a Weta ( or any other sail boat on the planet), you have to hike and/or trap to balance the boat out, which 99% of the AI/TI guys are just not willing to do). Another minor detail about adding sail area, once you start doing that, then you kinda need to start thinking about staying the mast (just FYI). It's a slippery slope (speed vs versatility).

Keep in mind though when adding that much sail area if you show the whole sail in 12 mph wind the boat will flip if you don't hike ( don't ask how I know this (lol)). Messing about with the boat, turning it into what I call a complex boat is just not what 99.9% of the AI/TI owners out there ever want to do (just FYI).
It's your boat and you can do anything you want or need to it to make it useful to you. There are no strict one design class rules (from the 60's) on these boats like on everything else, feel free to do what you want to do to make the boat do what you want it to be as long as you have fun (and the boat is safe) who cares.
FE

Its the mirage drive that sets these boats apart (and why I picked this boat). In light wind just add pedal power, I think you get a lot more speed than a larger sail would add.

Walt:
I agree with that, the mirage drive sets these boat apart from anything else out there, at this point I will never own anything else.
Bob

Even with less than a half-dozen sailing days in my AI I would have to agree with that.

In fact, I pulled the Mirage Drive yesterday when it was gusting to the high teens just to see how the boat compared without all that stuff hanging down there.

Frankly, I could not note a significant diff in how the boat felt.... and the conditions were gusty so any speed diff would have been lost on me.... Maybe speed and feel would have been more noticable in light air.

But I did feel distinctly uneasy without the availability of pedal power - especially in a relatively busy area with kayaks here, sailboats there.... the ability to turn on a dime using the Mirage Drive is downright addictive.... plus it's just nice to get some movement in the legs and do something besides just sit there.

I was racing low-end monohulls and at least staying with them - sometimes coming out ahead - by pointing directly into the wind and pedaling hard through the lulls and then bearing off and sailing the gusts.

Pedal-sailing, I could even stay with a WindRider 17 in moderate air - although he would walk away from me whenever a gust came through.

When I'm pedaling the Mirage Drive, it seems to run out of steam somewhere in the low sevens MPH-wise..... I get to, say, 7.3 and more pedaling ceases to raise the speed.... Strong enough of a gust was taking me up into the low eights, but not by virtue of pedal power.

But with, say, 10-12 mph wind, it would be nice to pedal it up to the low sevens and hold it there..... right now it's more like low sixes for me- and I am not sure how long I can keep that up.

Coming from paddling a surf ski, I am trying to get over my obsession with speed - and succeeding somewhat.... but the fact that I will be sailing in tidal bays will probably keep me thinking about it at least a little bit.

On the surf ski, I know from experience that I can get back to the beach from almost anywhere against the tide because I can hold a 6 mph+ pace for several miles back-to-back - and I can always find a shallow spot where I can dismount and take some time to recover...... but in an AI when the wind gets light and I'm limited to 4.8-5.0 mph, I would expect problems if I don't consider the tides before setting out.

Hence the thoughts about a sail that might buy me another 1-2 mph in light air..... Accepting, of course, that when the wind dies totally I'm still going to be SOL..... -)

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2015 AI in "Dune" - "The Grey Pig"
2017 Trailex 450 Trailer
Pre-September 2015 cradles
(anybody want to buy a slightly-used AI SpinKit?)
eMail: [email protected]

I find pedaling to be advantageous in any condition, especially high winds. Out yesterday, in the same conditions as you Pete and the drive makes the boat more stable in gusts and keeps speed up between them. I find the boat takes a short gust better with some speed, it accelerates instead of burying. In light air going upwind the pedaling increases apparent wind speed.
The only reason we don't peddle is when we are too tired from long bike rides the day before!
On larger sails, I don't feel the need but would like a boom to make downwind sailing and broad reaching more efficient. Gotta try one of the ideas presented on the forum next season.

The three I have seen are:

• Cutting a notch in the two-bladed paddle and using the paddle as a whisker pole.
  .
• A fold-up stick that, when unfolded and deployed acts as a whisker pole.
  .
• "Tweaker" lines as shown in https://www.youtube.com/watch?v=8uioFQ0mcq8, although I have not quite figured out all of what is going on there.

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2015 AI in "Dune" - "The Grey Pig"
2017 Trailex 450 Trailer
Pre-September 2015 cradles
(anybody want to buy a slightly-used AI SpinKit?)
eMail: [email protected]

if you want more speed put an engine on it, i did and with a 20knt wind and a motor its blistering

If you want better light wind performance, put the spinnaker on it. If the Hobie spin is too full for close reaching to weather, make one yourself that works like a genoa for light wind. The upside is that it also makes you faster downwind to. You folks with the spinnaker kit might want to consider having a couple spins available.

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R/Thom
SeaRail 19
Triak
BMW C600
Formerly Getaway with Custom Spinnakers
Formerly raced F24 Mk II

In full agreement with this. In light to moderate windss the spin will make a big difference in all points of sail except close hauled. Light winds actually become fun to sail in and you will find yourself hoping for light winds!

Edit; wrong quote earlier

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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

Thats all I go out in anymore is winds under 7mph, around here anyway that's 80% of the time, and if the wind gets over 10 mph we get 2ft washing machine chop that is very uncomfortable on my really bad back. Yea once in a while I like to go offshore and really push the boat, but man do I pay for it in back pain over the next month. I used to go out every weekend all year round and averaged around 15 miles a week, but the doctor told me I have to back off (sucks).
We love our TI and use it as our family boat.
FE
Edit: because we are typically out in 3-7mph winds 95% of the time the boat is fitted for light winds with 260sq ft of sail and outboards. The outboards are a safety must for us offshore in key west, it's darn dangerous down there (any open ocean sailing is very dangerous, and not really the intended purpose of the boat) just fyi.

If you are routinely in light air (under 6 kts), you might want to consider a windseeker sail. It is a half ounce spinnaker material, cut with a modest amount of camber (say 15%), free luff and high clew. It's purpose is to get you you moving in light air so the created apparent wind helps your mainsail to work. You would replace the spinnaker from the kit with this sail on light wind days.

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R/Thom
SeaRail 19
Triak
BMW C600
Formerly Getaway with Custom Spinnakers
Formerly raced F24 Mk II