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PostPosted: Tue Nov 22, 2016 8:30 pm 
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That looks like a slip knot. I like the bowline knot for fixing things securely.
https://en.wikipedia.org/wiki/Bowline

Keith

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PostPosted: Fri Dec 02, 2016 11:20 am 
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smithcorp wrote:
Would love a photo or sketches of c) please Tony - this is my greatest concern when carrying my kids, so keen to do this mod. i have seen you refer to it before, but I don't think I understand it properly


This is wretched excess because I have integrated righting lines with the ama keeper function, but the essential features are there:

  • Bungee from bow to the line. ..... (Home Depot, 1" flat... I cut off the hooks, sewed them into loops with a ring... but that's part of the wretched excess.....-)
    .
  • Quick connectors between line and bungee. ..... Probably also part of the excess, but convenient: https://photos.google.com/share/AF1QipP ... JaRW5TYzBR
    .
  • Line terminated on fore aka. .... Your line would be just a single piece instead of what you see here..
https://photos.google.com/share/AF1QipP ... JaRW5TYzBR

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PostPosted: Sat Dec 03, 2016 6:00 am 
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Wow! I agree Pete, simple is best. Here is the very simplest form of keep-out lines
Using stretchy rope (no need for bungees), tie a bowline round each front crossbar mount (eg where it joins the hull)
Bring the rope back to the vertical part of the rear ama on that side.
With enough rope to pass round the ama, add a snap-shackle.
Clip this to the rope coming from the front crossbar mount.
The ama will no longer fold in if you undo the ama brace, but will move a little bit until the rope tightens

You're done, once you do both sides.

To fol;d your amass, undo the snapshackle and bunch the rope into the mesh pockets next to the front Miragedrive .

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PostPosted: Sat Dec 03, 2016 6:27 am 
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You can also clip the line to the front of the lifting handle on the AMA on the newer boats that don't have the stainless padeye in the middle of the AMA.
Mounting the rope in the middle of the AMA also prevents both the front and rear AKA knuckles from popping out,( double duty). Actually the line also prevents the AMA's from falling off in the event of an AMA bungy breaking, or rattling around if the bungys are weak,(triple duty).
Take all of two bucks of rope and five minutes of your time to make it just one time.
Mine have been on my boat 6 yrs now, (same exact ropes and clips), at the end of the sailing day I just shove the ropes in the mesh pockets, it takes all of 30 seconds to put them on everytime I setup.
Simple as it gets.
FE


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PostPosted: Wed Dec 07, 2016 8:08 pm 
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Location: Melbourne, Australia
I finally had a go at making the keep-out lines.

I went for a single line for each side with a snap-hook to attach to the ama padeye.

For the crossbar end I used a simple overhand loop-knot (mainly because it's pretty easy to untie and adjust)

This makes it a very easy to remove the line.

Image

Image

I'm not that happy with the rather shallow angle of the line and I'm not sure it would be that effective out
on the water. I tried attaching to the front carry-handle padeye (on the hull) and this looked much better.

Image

If anyone has tried this setup on the water and can vouch for its effectiveness, that would be great.

Cheers,

Mike.


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PostPosted: Thu Dec 08, 2016 4:41 am 
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The setup you show in your pic is the exact same setup I've been running for 6 yrs. I've broken maybe 30 aka sheer bolts, and have had my aka bars disconnect at the knuckles maybe 6-8 times ( the rope also prevents the knuckles from coming out).
One other thing that drives me insane is the rattling around and stretching of the ama bungy's as your sailing, I have had a couple ama's over stretch the bungy's and fall off and swing out. The rope prevents all of the above.
I would definately recommend using stretchy nylon rope. Using light stretchy rope allows the joint to work like a shock obsorber. If you actually hit something hard, the rope stretches then breaks before any damage occurs.
The best way to test is to dissconnect the aka brace then pull on the ama, It shouldn't swing in too far , you only want to prevent capsize, that's all, so you can stop and replace the pin.
To check the knuckles just press the buttons and try to pull the aka bar out, It will come maybe a 3rd of the way out then stop (that's good enough).
Next take one of the ama bungys off and sail around a while, even with one bungy removed your ama should not rattle around at all.
If you don't like it do something different.
There is really nothing wrong with hobies original design as long as you stay within original design envelope, flat protected waters, and max speed around 6mph.
The problem is water force increases exponentially with speed, If you soup the boat up with massive sail sets or motors, or take it out in open ocean, you have exceeded the original design specs of the boat.
Hope this helps
FE


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PostPosted: Thu Dec 08, 2016 7:19 am 
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fusioneng wrote:
... hobies original design as long as you stay within original design envelope, flat protected waters, and max speed around 6mph.

I knew about the "flat, protected waters" part, but the 6 mph thing is new to me.

Seems awfully low.

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2017 Trailex 450 Trailer
Pre-September 2015 cradles
(anybody want to buy a slightly-used AI SpinKit?)
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PostPosted: Thu Dec 08, 2016 1:37 pm 
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About 6 mph was near top speed for the AI 1. The AI 2 is a couple mph faster (8-9 mph). The other day on a camping trip (fully loaded with 2 people), we hit 9 mph on my 2014 tandem. Of course, you can't sustain that speed but it was interesting to observe.

Keith

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"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: Thu Dec 08, 2016 2:32 pm 
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Chekika wrote:
The AI 2 is a couple mph faster (8-9 mph). The other day on a camping trip (fully loaded with 2 people), we hit 9 mph on my 2014 tandem. Of course, you can't sustain that speed but it was interesting to observe.
I see a lot of 9.something, a decent amount of 10.something and the occasional 11 and 12 - measured by SpeedPuck's 20-second averaging.

I am coming around to the realization that the sensation of speed is more in the type and height of chop than raw MPH.... was out on a dead flat lake a few weeks ago, seeing 9-10 and not feeling much different from 6.

OTOH in decent bay chop 7-9 feels pretty fast - especially upwind when the water situation is roughly equivalent to bodysurfing.... -)

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2017 Trailex 450 Trailer
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PostPosted: Thu Dec 08, 2016 2:44 pm 
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I'm not trying to poo poo the performance of the stock TI or AI at all, they actually perform pretty well. I was only trying to describe the water force against the AMA's increases exponentially with speed. And the water force in rough chop and hitting boat wakes can be quite powerful the faster you are traveling. For example if I'm cruising at 15mph and hit a wave or a boat wake, the nylon sheer bolt breaks everytime from the water force.
You can test this next time your out just by plunging your hand into the water at 3mph, the 6mph, then 9 mph, the force on you hand from the water pressure grows to the point where you can't keep your hand straight pretty quickly, this is just physics. I don't think hobie ever imagined anyone would be crazy enough to sail these boats 20mph, or in open ocean (way beyond the original design spec).
FE


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PostPosted: Fri Dec 09, 2016 1:32 am 
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Very helpful comments FE...

The rope is 4mm braided stuff, which has a bit of 'stretch'.

I've only assembled it on land, so haven't had a chance to test it on the water. It was just the shallow angle which made me
wonder how effective it would be.

I'm yet to see if the same lines will work with the A.I. amas (the test was just using the T.I. ones). I'll try clipping it to the
ama carry-handles.

Cheers,

Mike.

fusioneng wrote:
The setup you show in your pic is the exact same setup I've been running for 6 yrs. I've broken maybe 30 aka sheer bolts, and have had my aka bars disconnect at the knuckles maybe 6-8 times ( the rope also prevents the knuckles from coming out).
One other thing that drives me insane is the rattling around and stretching of the ama bungy's as your sailing, I have had a couple ama's over stretch the bungy's and fall off and swing out. The rope prevents all of the above.
I would definately recommend using stretchy nylon rope. Using light stretchy rope allows the joint to work like a shock obsorber. If you actually hit something hard, the rope stretches then breaks before any damage occurs.
The best way to test is to dissconnect the aka brace then pull on the ama, It shouldn't swing in too far , you only want to prevent capsize, that's all, so you can stop and replace the pin.
To check the knuckles just press the buttons and try to pull the aka bar out, It will come maybe a 3rd of the way out then stop (that's good enough).
Next take one of the ama bungys off and sail around a while, even with one bungy removed your ama should not rattle around at all.
If you don't like it do something different.
There is really nothing wrong with hobies original design as long as you stay within original design envelope, flat protected waters, and max speed around 6mph.
The problem is water force increases exponentially with speed, If you soup the boat up with massive sail sets or motors, or take it out in open ocean, you have exceeded the original design specs of the boat.
Hope this helps
FE


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PostPosted: Sun Dec 18, 2016 6:57 pm 
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Location: Victor Harbor, South Australia
After seeing a bloke in a TI come to grief in a strong wind and 2-3 metre seas (he didn't furl to relieve the force on his submerged ama). I also came up with the "Keep Line" idea in the case of a brace bar bolt snapping, but I thought to have lines fore AND aft on my AI2. In the above blokes situation his submerged aka caused him to stall...he lost forward speed rapidly... and a large following wave swung his ama FORWARD toward the bow. I reckon if he had a "Keep Line" attached to the AFT lifting toggle, it may have stopped the ama swinging forward and saved him flipping over. Luckily for him he had been aiming for the lee of a small island anyway and was able to stand in (rough) water about chest deep to drag the boat to a small beach.
Yes, as Tony says, a Keep line aft may get in the way a bit, but if conditions are pleasant "keep lines" don't have to be connected, but perhaps kept in the port an starboard stowage baskets for when we old but still bold sailors want to stretch the envelope in marginal conditions!
Cheers Ian.

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PostPosted: Wed Mar 08, 2017 11:41 am 
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FE,

From reading your various posts regarding "keep out lines", it seems like you nailed the subject down to the exact science. This is one of the last items I am left with on my TI project and I need your advice. I researched which lines would be most suitable for the job. Nylon ropes stretches the most, but a 1/4" has a breaking point of 550 lb to over a 1000 lb. You advised that exceeding 250Lb will result in damage the Akas. I put a considerable amount of time trying to find the right cord on Amazon but I'm not sure. I want the line to have the ability to break before it permanently damage other parts of the Island. Which line do you use? If it's an online item can you post a link?

Thank you so much for sharing your knowledge and experience here.
Hezi


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PostPosted: Wed Mar 08, 2017 1:55 pm 
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Here is the kind of test you need to do with your keep-out lines:




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


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PostPosted: Wed Mar 08, 2017 3:55 pm 
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Hezi:

Good point, I should have been more descriptive, I typically buy all my rope at either Home depot or Walmart, the cheapest I can find typically.

The 1/4" twisted nylon rope I am using on my combination heavy duty spray skirts/ keep out lines, mounted at the bow of the TI I bought at Home Depot ($10 bucks for 50 ft), it seems to be nice and stretchy and has a working load of 120 lbs.

I tested it by running into a dock (well that's what I'm telling everyone (lol)), the sheer pin broke as expected, then as the rope stretched it obsorbed my forward motion (like a rubber band) until the boat stopped, then pushed the boat backwards.

This is the rope I am currently using (much longer and mounted to the bow of the TI), 120 lbs working load:
http://www.homedepot.com/p/Everbilt-1-4 ... /202079605

My original safety line from 6 yrs ago was 3/16 dia (cheap rope), this also worked and had a 90 lb working load.
http://www.homedepot.com/p/Everbilt-3-1 ... /206094314

Most of the ropes on my boat are this 3/16 stuff.

Any old cheap Walmart type rope should also work.

FE


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