ama brace leash idea (definately TESTED now.. )

I liked this idea for ama safety lines using cleats viewtopic.php?f=69&t=54733 and maybe should have posted in that thread but this is a little too much off topic. I would probably have used the cleat idea (plus also maybe the bungee idea also suggested in that thread) but I always sit in the rear on the TI and you just end up with a lot of line to make something like that work.. so I tried something a little different.

Do you even need anything like this.. don’t know and that is a personal question but the wife and I are planning a trip to the Puget Sound in the fall and this boat will also get used a fair amount in Colorado at 8600 ft elevation so we deal with some cold water.. Anyhow, I wanted something that was very easy to set up and allowed me to collapse either side ama - mostly because I have to use guest docks at several lakes I sail at and this makes loading way easier. Fast setup and being able to quickly collapse and ama are two things I really like about the TI an wanted to preserve these.

The idea here was to add a line between the aka brace and the hull that was captive to the two ends of the brace so that if there was a failure at either the knob on the hull or the nylon sheer pin, the brace would still "mostly" work to keep the ama from collapsing.

This is what I ended up with and how well it at least works in the driveway (it has not been tested on the water).

For the failure conditions (either the knob connection failing or the nylon sheer bolt breaking), the ama will still fold back some and I measured how far..

Original ama position 100% out, 57 inches from hull center to center of ama
Ama folded all the way in (no leash) 33.9% out, 19 inches c to c
Knob failure 96% out, 55 inch c to c
Nylon bolt failure plus knob failure 86% out, 49 inches c to c
ama rotated forward, both nylon bolt plus knob failure 92% out, 53 inch c to c

Is this a good idea.. I don’t know.. I think "maybe sort of". But.. a little different so I posted it.

picture below - to "deploy" this, I simply clip the quick connect to the eye strap (which has a large aluminum backing plate inside the hull). If I need to collapse an ama, I just unclip the quick link. The line with the quick clip stays on the brace all the time.


picture below - at the other end of the brace where it connects to the aka


next two pictures below - what happens if there is a knob attachment failure




next four pictures below - what happens if there is a nylon sheer bolt failure plus a knob failure








picture below - this setup will also keep the ama from collapsing forward for both of the failure modes

Cleaver idea, Walt. I have my own safety lines (http://www.hobiecat.com/forums/viewtopic.php?f=70&t=7276&p=256156#p256156), but in case I lose an aka brace knob, or even the whole brace, I hope I remember your simple solution. One thing I'm going to fit into my tool/repair bag is 50-100' of good parachute cord for emergencies.

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

Keith:
I use that Para-cord for everything, handy stuff, I get mine at Home Depot ( around $6 bucks for 50 ft. Suprisingly strong and durable.
Bob

I recently picked up 100' of "TOUGH-GRID 750lb Paracord / Parachute Cord - This Is The Genuine 'Mil Spec' Type IV 750lb Paracord Used & Certified by the US Military (MIl-C-5040-H)" on Amazon. $16.47 It has 1553 ratings, 5 stars out of 5 stars. Seems good. I'm trying to figure out some roller to put it on which will keep it from being a mess in my repair bag.

Amazon http://www.amazon.com/gp/product/B00CJICDT2/ref=oh_aui_detailpage_o02_s01?ie=UTF8&psc=1

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

Thanks Keith, I have benefited a lot myself from ideas you and others have posted here.

FYI, that leash idea actually would work better on the AI than the TI. The TI has the brace going rear from the aka and the AI has the brace going forward from the aka. So the leash idea on the AI would be similar to the last picture I showed. After the failure, the amas would rotate a little to the rear and likely go about the 92% of original width that I measured for the TI ama's going forward. On the AI, the leash would still prevent the ama from collapsing forward as well as reverse just like on the TI.

A couple more pictures..

The leash just stays on the brace all the time so this is how its "stored". Last year I think I rigged some sort of sailing craft maybe 35 times and why I like fast setup. I think the TI on a trailer is about the fastest setup saiing craft I have ever owned (well.. except the AI I also had on a trailer). The only thing I will have to do with this setup is simply clip the quick connect, unclip when I want to collapse an ama (also easy to do when Im sitting in the rear seat and need to use a dock). But.. I still dont know how well it works in a real failure situation..


This is the backing plate for the eye strap on the hull .. stock 1/4 by 3/4 AL bar

Well.. didn't mean to but I got to test the heck out of the leash idea..

https://www.youtube.com/watch?v=IaAhNX5HMMA

The leash kept us from capsizing even though it was the down wind ama that had the sheer pin break and in pretty good wind. I also was able to change out the pin on the water - took about 7 minutes. This leash idea seemed to work well.

Uh... ya.. dumb for this to happen in the first place..

A self-fulfilling thread, huh? Lucky for us, everyone was equipped with dashcams.

Walt, you really deserved to capsize. You clearly were the "give way" boat...

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The Wind Is Your Friend...

No doubt I deserved to capsize (but didnt which was the point..). I think if you do a search on right of way and safety, you will find all sorts of posts on those subjects that you can contribute to. Hopefully this thread at least a little bit remains about this safety leash idea.

Well done then. We want to avoid dunking the wife at all costs.

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The Wind Is Your Friend...

I removed the video but what it showed was the down wind ama hitting the rear of another TI and it breaks the nylon sheer pin. The ama folds back slightly and then is caught by the leash and does not collapse. Without the leash, we would have gone over, probably turtled. Even though it is the downward ama that had the sheer pin break, we continued to sail (forcast that day was for 10 to 20 mph winds) a little before I noticed the pin had busted. I changed the pin on the water as the leash kept the ama out and the boat stable. The setup on this for the day sailing was to simply clip on the leash on both sides. In this accident, the ama tried to fold back but the leash would have also prevented the ama from folding forward. Worked well for how simple it is to rig.

Yeah, Walt, nice job getting that all on video. Definitely a "self-fulfilling" thread.

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

I’m scratching my head trying to figure out what this means?? lol..

Anyhow.. all the accidents I have been involved with or have heard about would have been protected by the leash idea because either something broke or came loose (like the knob unscrewing) out on the water and in both cases where I have had the sheer pin bust, there was an initial impact that broke the sheer pin but nothing after that. However, after my last incident, I got to wondering what if I had hit something very rigid such as the piling of a bridge.. The sheer pin would have busted like it was supposed to but then the leash might have tightened up and then something else busted.

So.. I put an extra "fuse" in the leash by cutting the rope and sewing two pieces together (see the picture). In the accident I just had where there was only the initial impact that broke the sheer pin, the threads I have sewn here would have easily held and I would have had the same outcome (no capsize).

And.. I’m messing with the original Hobie design which actually did exactly what it was supposed to do...

Walt, while I like your engineering solution to losing a sheer bolt, I can't help feeling that you have over-complicated things... I just clip a rope to the padeye on the ama, thread it through the mast holder just aft of the mast) and then off to the other side's ama. Job done, without any mods to the Island! I admit my solution doesn't cater for running the ama into something backwards, but realistically, the odds are small ehough to run that risk IMO. Of course another diagonal rope leading to behind the rear crossbar would provide this additional protection if required.

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

I prefer the back seat of the TI (I’m a little over 200 pounds) and it’s also important to me to be able to easily collapse an ama from the back seat while on the water. All the solutions I looked at were somewhat of a hassle to collapse either ama easily. As an example, when I come in after sailing I often use a guest dock. With my setup, I just unclip the leash (which is very accessible just under the knob) and then pop the brace off and the ama folds back. I can do this with either ama. All the other solutions I had looked at would require somehow working your way out to the ama itself to unclip or maybe climbing up to the mast to unclip.

Also, compare my setup time. Clip one side, the clip the other side. The leashes are already the rest of the way hooked up always. It’s the ease of collapsing an ama on the water and almost no setup time that drove a little different way of doing that. The TI is very fast to setup and that is one of the things I really like about it.

Like so much with sailing, you just have to pick your tradeoffs.. I really don’t want to defend this way of doing it – just a different way.. but it works well for what I wanted and how I use the boat.