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PostPosted: Mon May 26, 2014 6:14 am 
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Joined: Tue Jun 19, 2007 6:14 pm
Posts: 1862
Location: South Florida
OK, here is the nitty gritty on my wife's and my AI rocker.

Nancy's 2009 AI: bow 1 7/8" measured from ground to bow just before the bow starts to curve sharply. Stern, 3" measured at the very end of the keel.
My 2011 AI: bow 1 1/4". Stern, 2"

My 2011 AI seems to have less rocker, but I suspect the 2 boats are within tolerances. For a number of reasons, my boat has been resting on the garage floor or on my trailer, right side up, recently. This may have caused the hull to flatten some. Therefore, if I had to choose which is closer to factory specs, I would take Nancy's 2009 measurements, about 2" (5 cm) above flat in the bow and 3" (7.5 cm) above flat in the stern.

Keith

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I sail: Biscayne Bay, Everglades to Cape Romano, Ft Desoto, Cedar Key

"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


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PostPosted: Mon May 26, 2014 6:47 am 
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Joined: Wed Oct 06, 2010 2:53 am
Posts: 192
Location: Sollentuna, Sweden, Europe
Very interesting Keith.
Can you post a pic with some marks so I can see exactly how (and where) you have measured.

br thomas


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PostPosted: Mon May 26, 2014 6:51 am 
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Joined: Sun Apr 20, 2008 6:18 am
Posts: 1272
Location: Sarasota,Key West FL
Kieth:
I think you are correct that the front hatch is a major design flaw on both the AI and TI that Hobie appears to not want to address. Anyone who takes their adventure boat out in open water where there might be some wind and waves needs to take heed and be prepared to have to pump out a bunch of water in a fairly short period of time if going offshore.
In rough water if you watch the bow it waves up and down as much as 2-3 inches as you pass over the waves. So even if you have the hatch seal perfect on dry land, it will still leak some as the bow waves up and down because of the slender and weak bow with a big ole hole in it (hatch opening). If Hobie had designed the hatch with a cork in a bottle type seal (like the twist and stow hatches), it would be much more tolerant to the up and down motion of the hull. Even my TI with a braced bow took on a couple gallons of water when we were running high speed off shore a few miles out in open ocean the other day. We were doing quite a bit of downwind running with my daughter near the front of the tramp and the bow was not up and out of the water like normal. But we still had fun. Next time I do that I will tape over the front hatch opening.
I'm kind agreeing with keith here, his roids type seal appears to be the most forgiving of all the easy solutions I've seen.
Bob


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PostPosted: Mon May 26, 2014 1:51 pm 
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Joined: Tue Jun 19, 2007 6:14 pm
Posts: 1862
Location: South Florida
fusioneng--you are probably right that the bow hatch is poorly designed for this type boat, but I like it because it fits some large things in for camping trips. (That said, I no longer use the bow hatch like I did originally. It used to be full of things, some quite heavy. Now, all heavy things go on the hakas or rear surface storage. I want to keep the bow up to discourage diving and wave cutting.)

Kal-P-Dal--here are some pictures of my measurements on Nancy's 2009 AI. The measurement positions were the same on my 2011 AI.

Overview of bow measurement
Image


Close up
Image


Location of measurement This picture does not have a good angle, but the measurement was taken about 1 1/4" (about 3 cm) behind the pad eye, above.)
Image


Keel measurement This measurement was taken at the very end of the keel.
Image


These measurements are not precise. I feel there is considerable variance in boats and precise measurements are overkill.

Keith

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I sail: Biscayne Bay, Everglades to Cape Romano, Ft Desoto, Cedar Key

"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


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PostPosted: Mon May 26, 2014 7:47 pm 
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Joined: Fri May 23, 2014 7:30 am
Posts: 10
Great info and pics! I think it would be safe to say if you are around the 3in mark fore or aft it would be "in tolerance". That is good to know, thanks!


Ok! Tested out the "gym mat" method shown by yakass and wow, what a difference! It was definitely the front hatch that was leaking. I sailed for 6 hours today, stopping to check the leak status several times, and I am happy to say I had to bail out around 6 cups worth after 6 hours. After inspecting my fancy gym mat seal, the imprint of the hull seal is quite uneven to say the least. While this method didn't stop the leak 100%, it dropped it by 95%.

It was a great sailing day, with around a 2-3ft chop and 10-12 knot winds. Water splashing over the bow over and over and the occasional sumersion under a larger set made for an ideal test. The hatch rode at its normal height, or maybe slightly higher. I made sure to hit all the points of sail while out to make it a valid test. Huge improvement on the front seal, and I'm not sure why Hobie would not use something so simple as a factory update.

I may try the ROIDS seal next weekend, although I see it giving me the same results I saw today. Either method would drastically improve the uneven fit of the front hatch. The fact that it leaks at all, is a major design flaw. Boats of this nature only stay afloat because of the air ballast provided by the SEALED interior of the boat. Any traditional boat which relies on displacement to float would sink with as many holes in the deck as our kayaks have! The simple fact that the only thing keeping the boat afloat are the hatch seals, and those are not 100% would have been a deal breaker for me if I had not already purchased it. I love so many aspects of the design and it's versatility, but in order to be a boat, it needs to float! It is very possible to make a simple design change to that hatch to make it airtight. A male and a female mating system with a huge oring, a hinge on one side, and cam locks on the other 3. Problem solved.


I know Hobie reps monitor these forums, and post from time to time. If you are going to command the upper tier of the price point in your field, you will be held to a much higher standard. If my $600 kayak from Dick's sporting goods leaked, I would chalk it up to not buying a quality product. When my $4,000 AI or $6,000 TI has a leak from one of its main hatches, that is inexcusable. Relying on a compression seal while using an injection molded material that is inherently mailable is asking for trouble. It is a shame, because the island is an amazing boat is almost every other regard. I almost feel bad being so critical, but regardless of the cause, a leaky/sinking boat deserves a second look by any boat manufacturers design team.


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