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PostPosted: Wed Dec 02, 2015 9:37 am 
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walt wrote:
In my opinion, its much more likely that the ball came unscrewed (maybe because not enough loktite was used in production) so that the arm was no longer anchored to the hull and now the ama moving back and forth caught the arm just right and broke the sheer pin. I know another person with a TI who also had the ball unscrew and had a similar result (capsize).

Walt, I find it interesting that you do not believe the connector knob (ball) could come unscrewed as I suggest. But, you don't seem to have any problem with the knob coming unscrewed on your friend's boat. How do you speculate that came unscrewed and fell out underway?

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

"Less is more" Anon


Last edited by Chekika on Wed May 04, 2016 6:43 am, edited 2 times in total.

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PostPosted: Wed Dec 02, 2015 11:03 am 
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Chekika wrote:
tonystott wrote:
...In actual fact, it would seem that all the akas are quite similar (tube thickness etc), so the force needed to bend them would also be similar.

But, that is my point, the force applied to the pin must be quite different for the 3 boats.

Yes, yes, where is Fusioneng?? Maybe he is working up a lengthy statement.

Keith

Keith, the shear pin is designed to break before any damage occurs to the aka. Given that the akas in all the Islands are very similar, the force required to damage an aka must also be similar. Increasing the breaking strength of the shear pin simply reduces the safety margin between breaking the pin and breaking the aka.

The forces which are applied to the pin by hitting waves, or an object etc might well be different depending on the Island model involved, but this is independent from the relationship between the breaking limit of the shear pin and the bending point of thre aka. This is where keep-out lines do their job

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2012 Tandem Island "SIC EM" with Hobie spinnaker


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PostPosted: Wed Dec 02, 2015 12:13 pm 
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Tony, we may be talking about 2 different things. I'm saying the forces on the shear pin are different for the 3 boats, so, in order to prevent premature breaking of the pin on say the AI 2, you need a new stronger pin. From my experience, I don't want shear pins breaking unexpectedly on the AI 2, even though those pins may be fine for the AI. Again, my keep-out lines are designed to stretch and allow the shear pin to break if a solid object is struck.

I have another gripe with Hobie. Walt says that unscrewing of the aka connector knob is a problem, and dpstivers noted that after a long trip in rough waters one of his knobs was loose. It can be avoided perhaps by properly gluing the knob screw in with Loctite (blue, I believe.) I think part of the problem with the knobs coming unscrewed and falling out is the short shank of the useful threaded screw. It is only about 1/4"--pretty short and, apparently, easily unscrewed by the action of the aka brace arm. I just unscrewed both of my knob screws on my new (out of the box) 2014 Tandem, and each had a small amount of some black glue in the top 1-2 threads, almost like it was added after the screw was set. So, once I broke each one loose, it unscrewed easily.

It seems Hobie could solve this connector knob problem by (1) using a longer screw--instead of a 3/4" screw with 1/4" of usable threads, use a 1" or even 1.5" screw, and (2) use more glue.

Finally, it is interesting that dpstivers apparently went through some major waves w/o breaking any shear pins on his AI 2. If the wave is large enough, you are not surfing over the wave, but riding over the wave and crashing the bow and akas into the trough below. The point I was making initially, based on Snore's comments, is that in rough chop surfing over a wave with your bow allows the leeward aka/ama to bury itself into the wave. This puts considerable pressure on the shear pin and may lead to breakage. The AI 2 with its larger bow may aggravate this problem. Solution: a stronger pin for the AI 2.

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: Wed Dec 02, 2015 2:15 pm 
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Something Keith wrote earlier

Quote:
I guess I'm suggesting that the aka shear bolt is not appropriate for the AI 2, at least the way I use the boat. I'm still trying to figure out why that shear bolt broke. This is my best explanation.


Before the incident, I am assuming that everything worked fine and after the incident the "facts" are that the sheer pin was broken AND the ball or Knob was gone. Its very unlikely that both the sheer pin and ball failed at the exact same time so either the sheer pin failed first and this resulted in the ball screwing out - or the ball screwed out first resulting in the sheer pin getting busted. It makes a lot more sense to me that the ball worked its way out while sailing (which would be a manufacturing defect), the brace came loose and this resulted in the sheer pin breaking. My personal opinion (which is based on speculation just as yours is) is that your conclusion above is not correct and just wanted to throw that "doubt" into the mix and explain why in case you were convincing any one that Hobie did an inadequate job on the design - which I dont think is true with the many years of experience I have with these boats. My opinion is that if you put the new ball back in place with the proper loctite application, you solved your problem.

Weve beat this topic up more than any one is still interested in .. Given the amount of time these boats have been around and the number of them, it is likely that there have been some cases of a sheer pin failing while doing nothing more than sailing. But is there any evidence of a real design issue? Also, putting a little stronger sheer pin may be an improvement (not a problem I think I need to solve at all) but you probably would need to do some impact testing (like Hobie likely did in the design phase) to make sure that you havent created more of a problem than you solved.

Quote:
I have another gripe with Hobie. Walt says that unscrewing of the aka connector knob is a problem, and dpstivers noted that after a long trip in rough waters one of his knobs was loose. It can be avoided perhaps by properly gluing the knob screw in with Loctite (blue, I believe.) I think part of the problem with the knobs coming unscrewed and falling out is the short shank of the useful threaded screw.
I dont know how big of a problem the knob unscrewing is. But I know it has happened at least once. When I got my TI, I checked both of the knobs and they were both tight and had been glued in. I did a good job with loctite putting them back in. Plus I periodically check them to make sure they are still very tight.


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PostPosted: Wed Dec 02, 2015 5:23 pm 
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In the vein of "one good comment deserves another," here is a blowout post:

There is still considerable interest in this topic judging from the hits. Of course, maybe viewers simply like a good argument. I disagree with almost everything you say since it is predicated on assuming your argument is correct (knob worked lose, aka/ama collapsed, shear pin somehow broke—in that sequence.) There have not been a lot of complaints about the connector knobs unscrewing. As far as we know, only your one case, Walt, has resulted in capsize, and we know zero details about that. How do we know it was not a case, like mine, of the aka brace shear bolt breaking, capsize, followed by unscrewing the knob? If the knobs are glued in properly, they should never be a problem; although, I recommend to Hobie that a 1" bolt (not 3/4") be used with the knobs for an added measure of safety. Shear bolt breaking are always going to be a problem (especially, if one capsizes!) Of course, as Fusioneng says below, the shear bolt breaking is normal--just doing what they are supposed to be doing.

Here are some quotes from my original thread about the capsize (viewtopic.php?f=70&t=54465)
fusioneng wrote:
Mike:
I wouldn't think so, The TI with much more weight capacity larger AMA's has the same sheer bolts and AKA's, and arms (just reversed). There are a lot of TI's out there and the boats have been proven to be quite durable and capable. The new AI looks like another remarkable craft from Hobie. It appears the vast majority of AI/TI users with stock boats and sailing at normal stock boat speeds have no issues with the sheer bolts. I'm sure Keith’s accident was a fluke occurrence related to his speed, rough conditions where he hit a wave wrong. When you are moving fast the force of the water on the AMA from a boat wake or rough seas is much greater.
The problem comes up not from the sheer bolt breaking (it is doing what it's supposed to do as a sacrificial component). It's what happens immediately afterward that is the problem (possible capsize if the AMA folds in completely). There are several ways to mitigate the problem, tramps, HAKA's, and simple safety backup lines, all pretty well documented on this wonderful forum.
The force of water on a moving object grows exponentially as your speed increases. Only if your boat is massively modified and goes very fast, is when all those little things like AKA sheer bolts become a big issue (totally speed related). My opinion is even on a stock adventure boat you can't predict when that huge boat wake or rogue wave is going to hit you and sheer the nylon bolt, why take the chance is my thought just add a simple safety line (I think it should be in Hobies accessory catalog personally (with a clip on each end so fishermen can unclip it to swing their AMA in), a really simple safety mod especially with the offshore crowd.
Just my 2 cents
FE



Yakass wrote:
This is why I replace the nylon nut (bolt) with a stainless clevis pin. I am well aware of the risk of potentially more serious damage to the boat, but I'm also pretty confident that I'm not about to sail into anything, or take on surf I can't conquer. I've had one fail in the past, but luckily it was the windward ama, not the far scarier leeward side. For me the risk of insta-capsize due to a failing shear bolt is greater than the risk of collision or catastrophic landing. Mind you, this is advice I am very hesitant to give out, and I don't raise it with customers unless asked about it (with added caveats). I do, however, recommend to all Island owners to check those bolts regularly (not that it would have helped in this instance) and point out that they are provided 4 spares for a reason.



Buckaroo wrote:
Keith, thanks for taking the time to post a detailed account of your mishap. It's great food for thought as I rig things on my TI.

I like the idea of a grab line between the aka braces for hanging on to the boat and to help righting it in a capsize. I'm going to experiment with this. In the sailing book I'm reading they talk about righting a capsized dinghy using a sheet thrown over the hull to the side you are pulling from.

All the talk about the shear bolts also has me thinking about:
Does the risk and potential danger of an unexpected sudden capsize outweigh the potential damage to the boat of using a stronger bolt in the shear pin location ?
What is the actual damage likely to be if you hit something hard while using a bolt instead of plastic shear pin ?
How often do people actually run into things with the amas hard enough that it would cause damage ?
If the plastic pin can break just from hitting a wave or boat wake with a buried ama, maybe an aluminum bolt or an aluminum bolt with a drilled body would make a more appropriate shear pin ?

Just me thinking out loud, I like to tinker with things.

Chris



KayakingBob wrote:
3 of the 4 first AI's I owned had a failure of a aka shear-bolt on their first or second sail. We think it was shipping and handling to Hawaii and finally to Maui, more than a defect. Many changes, including in the packing and handling of the boats in 8 1/2 years, but it still could happen.

Great discussion on a bad event that turned out well, but with much loss of long-time collected and expensive (treasured?) equipment and tools. It could happen to any of us. I'm revising how I carry emergency equipment (again!) with the thought of access while on the water in too-rough conditions, or even while in the water! Like how to get the one needed item without loosing most of the others.

I've got the leashing down (inside the hull and out) after many years (and minor loses) while white-water canoeing. But, I still need to refine, one-handed access to any single piece while keeping the boat controlled in wild conditions or while in the water. With enough work I could get my epirb out of my pelican "ditch" box while in the water, but probably not without loosing most of the other loose important rescue and repair parts, tools and gear in the box.

Be safe out there. I'm glad we are all here to talk about it Keith.


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


Last edited by Chekika on Fri Dec 04, 2015 9:32 am, edited 2 times in total.

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PostPosted: Wed Dec 02, 2015 11:37 pm 
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Yakass wrote:
This is why I replace the nylon nut with a stainless clevis pin. I am well aware of the risk of potentially more serious damage to the boat, but I'm also pretty confident that I'm not about to sail into anything, or take on surf I can't conquer. I've had one fail in the past, but luckily it was the windward ama, not the far scarier leeward side. For me the risk of insta-capsize due to a failing shear bolt is greater than the risk of collision or catastrophic landing. Mind you, this is advice I am very hesitant to give out, and I don't raise it with customers unless asked about it (with added caveats). I do, however, recommend to all Island owners to check those bolts regularly (not that it would have helped in this instance) and point out that they are provided 4 spares for a reason.



I am with Yakass in this. I think the same way.
Also that if you choose to go with nylon shear bolts it is necessary to use keep-out lines.

best regards
thomas


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PostPosted: Thu Dec 10, 2015 11:41 am 
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Done! First Sail With My Tandem

I put on keep out lines, KB’s keeper lines, padeyes for leashing the Mirage drives, extra padding for the seats, changed the rigging for better (3:1) leverage from the rear seat, etc., etc. There were more things I could do (and will do), but Michael & Bonny were visiting from New Mexico, and Michael wanted to go sailing. This was one reason I bought my new, out-of-the box 2014 Tandem: guests.

We met on Sanibel on the west coast of Florida. For those of you who do not know, Sanibel Island is a large barrier island about 70 mi north along the coast from our usual haunt of Chokoloskee. Sanibel Island is a beautiful place, although it is beginning to suffer the pains of modern growth. Sanibel Island…

Image


Our launch was immediately next to the causeway connecting the main land to Sanibel Island.

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Our first day sailing was in light winds (10 mph and less). This is Michael, and we are near the Sanibel Causeway. I don’t have bridges anywhere I sail. This one made me a bit nervous, but it was not a problem as long as we crossed under at the highest span. Michael thought it was great.

Image

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Fortunately, the next day we had some winds, about 15 mph when we got to the launch. Now, I have a slightly embarrassing story about our launch on this second sail. This picture is of the launch during very light winds.

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The launch ramp is only about 2 Tandems wide. This is Michael at the end of the 2nd sail. Winds are about 15 mph coming almost directly into the ramp.

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To launch, I had the boat headed out on the left side of the ramp. Michael was in the front seat. I planned to hop in (no rudder at this point), implore Michael to pedal, drop the rudder, and clear the end of the docks. First try, things did not go as planned. I didn’t get the rudder down fast enough. The winds turned us clockwise and forced us back, and against the dock on the right. The incoming waves jammed us into the dock. POP! It took me about 1 second to realize that we had broken an aka brace shear pin. The “pop” was quite loud. Michael asked, “Why did it break so easily?” I laughed and responded, “It didn’t break easily. We gave the right ama/aka a pretty good whack on the dock.” I laughed again. No damage done. The shear pin had done what it was supposed to do: break!

Image


It took a few minutes to change the pin, and we launched again. While it was not without excitement, as we just barely cleared the end of the right dock (“Pedal, Michael. Pedal hard! Pedal harder!!”), we were finally in open water.

We had a nice sail. Michael did not have any foul weather gear. I knew the front passenger of a Tandem got pretty wet, so I had brought a small tarp for Michael to “wear.” He was happy.

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We made it down to the Pt Ybel lighthouse on the Gulf of Mexico.

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On one tack, we were doing 6.5 mph. It seemed effortless. I thought that was pretty good, because I had the sail furled a couple wraps.

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I’m sure Nancy and I will enjoy our first camping trip. I’m looking forward to it. It is definitely less work than using 2 AIs when guests arrive. Yes, I would rate the Tandem a success.

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


Last edited by Chekika on Wed May 09, 2018 5:38 pm, edited 2 times in total.

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PostPosted: Thu Dec 10, 2015 6:43 pm 
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Welcome to the in-crowd Keith! :D :D :D

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2012 Tandem Island "SIC EM" with Hobie spinnaker


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PostPosted: Fri Dec 11, 2015 7:26 am 
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Thanks, Tony. "In-crowd?" Perhaps, but sailing solo, I'm pretty sure, my AI 2 will continue to be my strong favorite. You know, Hobie has finally upgraded the AI to the AI 2, and I think it will be quite successful. Obviously, for more people on board, the Tandem will be great. I'm very lucky to have both.

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: Mon Dec 14, 2015 9:12 am 
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The more I compare my "new" out-of-the-box 2014 Tandem with my AI 2, it appears that Hobie simply took the Tandem model, cut one seat out, glued it back together, and called it the 2015 AI (the AI 2). There may be some changes that are hidden or not so obvious, but looking at them and comparing their sailing characteristics, the AI 2 is just the Tandem minus one seat. Oh yes, the Tandem sail was modified to fit the AI 2.

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


Last edited by Chekika on Mon Dec 14, 2015 11:58 am, edited 1 time in total.

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PostPosted: Mon Dec 14, 2015 11:08 am 
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Keith, I think the bow is designed better on the AI 2 than the TI and I would expect Hobie to incorporate similar on the TI the next time the molds get modified, but that may not be for a while.

Other than that, I agree, a TI less one seat = the AI 2.

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PostPosted: Mon Dec 14, 2015 12:06 pm 
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KB, my AI 2 has been stored in the garage on its rails since last spring. I really have not been able to compare their appearance very well. At some time, I'll do that. Probably, when they are both on the trailer together (next year!)

You are right about the bow. The Tandem bow is very stubby. The AI 2 bow is long and narrow, and it can accommodate a mirage drive through its extended hatch. The difference surprises me, because, although it has been some time since I sailed the AI 2, I thought my 2014 Tandem handled very similarly.

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: Sun Dec 27, 2015 11:57 am 
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Trips--2016 These are some of the currently planned trips.

FLM-Cape Sable, Jan 7-10, 2016 I’m tentatively scheduling 4 days, 3 nights, (Thu-Sun), but you could do Fri-Sun, or even Sat-Sun. Depending on the winds it may be at East Cape Sable or around the corner to NW Cape. If we have good winds, the sailors in the group might go directly from FLM to NW Cape—about a 20 mi trip. But, if we have several kayakers, who are not used to doing a 20 mi day, we could camp at ECS—ECS is one of my favorite places. We will look at the weather and participants after Jan 1 to make a decision about our itinerary. Members: Alex Oancea, Nancy & Keith Wellman, maybe Cindy Augustine

Chok-FLM, Jan 20-26, 2016 The itinerary is Jan 20-21 PAV, Jan 22 PAV to HiLand Beach, Jan 23 Fish, beach comb, & relax on HiLand, Jan 24 HiLand to NW Cape, Jan 25 Fish, beach comb, & relax on NW Cape, Jan 26 NW Cape to FLM. The End You can do various parts of this trip.
Members List:
    Pavilion Key portion—Kathy Kenley, Bob Smith & Wife, Josh Morgan, Toby Nipper, and all Thru Trippers total: 12
    Thru Trippers—Haynes & Dianne, Tom Lachner, Jim Quinlan, Martin Cooperman, Rick Parks, Me
    Highland Beach only:—Alex Oancea
    Cape Sable—Royd Whedon & Allison, Charlie Fast, Sharon Hukowski, and all Thru Trippers total: 11

Chok-PAV, Feb 18-21, 2016 We lost Tom Turner recently—unexpected, and Tom was too young. Tom’s wife, Debbie, can make this trip; so, we will definitely plan to have a few stories about Tom and raise a toast or two. Again, this is a trip where you can do it all—4 days, 3 nights on PAV, or Fri-Sun, or only Sat-Sun. Tides are good for coming and going on any day. Fishing for sea trout and maybe a red or 2 should be good. Pavilion Key, with its mile-long beautiful beach is fun for everyone, the “Jewel of the Everglades.” I hope you all can make it for this special occasion. Be sure to mark these dates on your calendar now. Members: Debbie, Bob Smith & Wife, me

Everglades Challenge, Mar 5-12, 2016 Not one of our trips, but some of us will be camping at Ft Desoto on Mar 3-4 to watch the activities.

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: Sat Jan 02, 2016 3:07 pm 
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These kids know how to sail!

Hope you enjoy these pictures I took (from our Tandem as Nancy piloted from the front seat) of young sailors from all over the world vying for some Olympic position here in Biscayne Bay off Coconut Grove. It is an annual scene this time of the year.

Image


Look at the amount of sail out on this little mono hull.

Image


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


Last edited by Chekika on Mon Jan 04, 2016 1:47 am, edited 2 times in total.

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PostPosted: Sat Jan 02, 2016 3:13 pm 
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2nd Bungee on Tandem Ama

This is a small but important mod to our Tandem. Used SS eye bolts screwed into the ama. Added 1/4" bungee cord tied with a Figure 8 knot--a great knot, BTW.

Image

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


Last edited by Chekika on Sun Jan 03, 2016 3:47 pm, edited 1 time in total.

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