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PostPosted: Wed Dec 21, 2011 2:24 pm 
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I agree with Matt Miller. I have owned both AIs and TIs. If you could look carefully at the interior of both bows, there really is not a lot of structure to withstand the impact and torque which would hit the front of the Kayaks in really nasty seas if a wave deflector were installed.
You could install a deflector but there is a good chance of tearing a piece of the bow right out if a large enough wave hit while you are maxing the speed of the kayak. The interior would flood within one wave period.
I had a fiberglass expert look at my AI and he said the same thing as Matt...the bow would have to be built up a lot to withstand the wave impacts.
So probably the only way that Hobie would be able to have deflectors on either hull is to design a whole new bow structure. Not a retro-fit.


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PostPosted: Wed Dec 21, 2011 5:20 pm 
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OK - thanks for the update.


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PostPosted: Mon Dec 26, 2011 6:34 am 
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As far as the wave deflector withstanding wave impacts and hull stress; just make the deflector out of a flexible material. Rubber material like the mirage flippers should provide some wave deflection while bending quite a bit when under duress. As the boat rose and fell the side bow flipper/deflectors would flap up and down like the way a sting ray swims.

In fact, someone could even experiment with a pair of old Turbo fins mounted one on either side of the nose just to see how well it would work on spray and wave deflection.


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PostPosted: Mon Dec 26, 2011 8:57 am 
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Yakaholic wrote:
As far as the wave deflector withstanding wave impacts and hull stress; just make the deflector out of a flexible material. Rubber material like the mirage flippers should provide some wave deflection while bending quite a bit when under duress. As the boat rose and fell the side bow flipper/deflectors would flap up and down like the way a sting ray swims.

In fact, someone could even experiment with a pair of old Turbo fins mounted one on either side of the nose just to see how well it would work on spray and wave deflection.


good idea!

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PostPosted: Mon Dec 26, 2011 5:57 pm 
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So far, so good.

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PostPosted: Mon Dec 26, 2011 6:29 pm 
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Location: South Florida
NOHUHU, how is that deflector working?

Keith

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PostPosted: Tue Dec 27, 2011 11:36 am 
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It doesn't hurt. It helps somewhat in swells, sailing both up and downwind. Changing your sailing position has more of an effect on the AI/TI bow.

We have not tried a bow skirt yet.

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PostPosted: Tue Dec 27, 2011 1:06 pm 
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NOHUHU,

Could you be more specific about changing your position to reduce diving. Do you mean hiking out on the tramps? Or, sliding back into the cargo area?

Keith

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PostPosted: Tue Dec 27, 2011 9:17 pm 
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Both work Keith. While hiking out you can counteract the pull of the sail, so it may be a bit more effective, but just leaning way back in the cockpit or sitting over the rear xbar makes a difference. So will trimming the sail if you have too much out on a downwind run.

Using a Haka bench or a TI tramp you have more options cuz the ballast can quickly and easily slide in any desired direction. As a passenger moving around the TI, I have seen a foot or so make a big difference on the behavior of the bow. Factors change constantly as you sail so it's great to be able to fine tune things on the fly.

It may seem odd but I like to put my weight forward on fast surfing runs, cuz it facilitates catching the wave and gaining speed. Stuffing the bow and taking a bath the end is just gravy to me. :mrgreen:

If someone was really concerned about this, the best thing may be to load the boat with extra weight in the rear and sit back on the crossbar.

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PostPosted: Thu Aug 09, 2012 10:02 am 
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I took the time to read this entire thread carefully. Frankly, within the confines of what I think this boat was designed for, it seems to perform exceptionally well. Obviously, you can push the envelope with anything and experience some shortcomings. Not to mention that any redesign to make it perform better at that edge of the envelope could cause something to be sacrificed at the opposite end where most the sales were intended in the first place.

I tend to prefer my AI punch or cut through waves. I've accepted that this makes for a wetter ride, but one which seems flatter and faster to me.

A bow deflector or anti-pitchpole device would seem to work in both directions - the same thing that keeps the bow up, could keep it down (for longer periods) if you were to submerge it.

I wonder if there might not be a better compromise. A more voluminous bow would be slower, unless that volume could be kept out of the water until it was really needed. What I'm about to suggest is going to sound very crude, but perhaps it's worth a try. If you took a standard pool noodle, about 3 to 4 feet in length, split it lengthwise and then folded it midways, putting the fold on the bow and the remaining lengths down both sides of the hull, a 90-degree fold at the hull to deck junction along the entire length, it would seem you'd have greatly increased volume to lift the bow during periods of large swells or waves, or when running in a particular direction. I don't believe it would plane downward when submerged, at least not to any serious degree. The bouyancy of these things is incredible and would almost certainly pop the bow up quickly if submerged.

Otherwise, the "noodle" isn't in the water and this small amount of additional surface and weight has no practical effect on anything during the sort of operations most people operate their AIs in.

Just a thought. I may play with it to see if I've overlooked something important.


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PostPosted: Mon Mar 25, 2013 8:11 pm 
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Hi everyone I have been away for a long time, finishing my Engineering degree off in Germany...

Anyhow I just found this vid on Youtube and thought I'd share it, enjoy :)

[youtube]http://youtu.be/VqdQL90sDVo[/youtube]



edit (I'm not sure why the youtube preview isnt working but please have a look on youtube )

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PostPosted: Tue Mar 26, 2013 12:03 am 
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Location: Aussie living in San Diego, CA
Tom Kirkman wrote:
If you took a standard pool noodle, about 3 to 4 feet in length, split it lengthwise and then folded it midways, putting the fold on the bow and the remaining lengths down both sides of the hull, a 90-degree fold at the hull to deck junction along the entire length, it would seem you'd have greatly increased volume to lift the bow during periods of large swells or waves, or when running in a particular direction. I don't believe it would plane downward when submerged, at least not to any serious degree. The bouyancy of these things is incredible and would almost certainly pop the bow up quickly if submerged.


Hi Tom - you might be interested to take a look at this website where an enterprising Aussie has tackled the problem for boats, more for stability and safety but also for spray reduction. Your idea of the pool noodles is actually close to what he came up with using polyethylene closed cell foam, which has a lifespan of 30 years. The profile for boats looks too bulky for a kayak but perhaps a cut-down version of the boat collar might work? He says the foam is shaped by routing.
http://www.kaptenboatcollar.com/index.html

There is also a company that makes a vinyl extrusion as a spray rail that is glued on to the hull (no holes) specifically designed as a spray deflector that might work too. Its expensive and I have been in touch with them about using it on a kayak but they don't seem very interested in discussing it. They are called "Smart Rails" and their website is
http://www.thesmartrail.com/

This next link shows the profile of the spray rails.
http://www.thesmartrail.com/product/ins ... ctions.htm

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PostPosted: Tue Mar 26, 2013 6:52 pm 
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Way early in this thread someone mentioned adjusting the height of the AKAS to counteract dive. Seems easy to add an extension to the short bent end of the AMAS that go into the AKA hole. Add 4 inches to each front mount and get 2 degrees of rise on the bow. PM me all royalties derived from this idea.


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PostPosted: Tue Mar 26, 2013 7:07 pm 
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ppicker wrote:
Way early in this thread someone mentioned adjusting the height of the AKAS to counteract dive. Seems easy to add an extension to the short bent end of the AMAS that go into the AKA hole. Add 4 inches to each front mount and get 2 degrees of rise on the bow. PM me all royalties derived from this idea.
Or, you'll sink the Amas first, collapse and pitchpole,.. :o


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PostPosted: Wed Mar 27, 2013 4:20 am 
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My friend Roger has been experimenting with foils on the bows for a while. If you want to explore, here is his site:

http://www.wingsailor.com/html/trimarans.html

One of his little trimarans wound up on this site:

http://www.multihulldesigns.com/designs ... 12_tri.htm

Here it is:

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My opinion is that the AI is fun just like it is, and this is one of the more entertaining things it does...

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