Tank Strap Advice

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Adding to what kwinter said, there's also a technique that is a lot easier to show than describe.
When it's wet, reasonably tight and under tension:
- keep pulling on the strap end while "rocking" the buckle a few times. This incrementally tightens it even more.
- then like kwinter said, keeping tension with the cam buckle position (partly closed), thread through the last slot, and
- then close by pulling on the end of the strap to maximize leverage.

That's the procedure I was talking about, but it included the "rocking" which I usually omit.
 
- then close by pulling on the end of the strap to maximize leverage.

I have often heard that pulling on the strap increases leverage. But how?

The strap doesn't increase the length of the lever (the buckle) since it isn't rigid.

I think an analogy would be attaching rope to the handles of a wheelbarrow...it doesn't offer any mechanical advantage.
 
Adding to what kwinter said, there's also a technique that is a lot easier to show than describe.
When it's wet, reasonably tight and under tension:
- keep pulling on the strap end while "rocking" the buckle a few times. This incrementally tightens it even more.
- then like kwinter said, keeping tension with the cam buckle position (partly closed), thread through the last slot, and
- then close by pulling on the end of the strap to maximize leverage.

The issue with your son is most likely technique. As pointed out by kwinter and knotical, you want to use the buckel as a ratchet.

[video=youtube;emnI_EWdqq8]http://www.youtube.com/watch?v=emnI_EWdqq8[/video]
 
I have often heard that pulling on the strap increases leverage. But how?

The strap doesn't increase the length of the lever (the buckle) since it isn't rigid.

I think an analogy would be attaching rope to the handles of a wheelbarrow...it doesn't offer any mechanical advantage.

Good point. It's how I've been doing it for years. Now I'll have to get out a BC and cylinder to see if there's any benefit to my old habit.
 
I have often heard that pulling on the strap increases leverage. But how?

The strap doesn't increase the length of the lever (the buckle) since it isn't rigid.

I think an analogy would be attaching rope to the handles of a wheelbarrow...it doesn't offer any mechanical advantage.

You're misinterpreting the physics. When your hand pushes the cam band over, the centroid of the force is halfway down the cam. When you use the strap, it's much closer to the end....it's about twice as far out.
 
You're misinterpreting the physics. When your hand pushes the cam band over, the centroid of the force is halfway down the cam. When you use the strap, it's much closer to the end....it's about twice as far out.

That definitely makes sense, although I don't believe I have misinterpreted anything.

When I close my buckle I put the base of my palm on the end of the buckle (actually on the strap as it is fed through the final slot) and push. I suppose I am not exactly on the end like the strap is, but I think a centimeter of difference hardly results in a mechanical advantage worth considering.
 
OK, I just played with some gear and think the benefit of pulling on the strap is:
- something to grab on to.
And the benefit of using the end of the strap is:
- can jerk it if I've rocked the cam to the max.

thank you, nimoh (really)
 
OK, I just played with some gear and think the benefit of pulling on the strap is:
- something to grab on to.
And the benefit of using the end of the strap is:
- can jerk it if I've rocked the cam to the max.

thank you, nimoh (really)

I do agree there may be other advantages to using the strap (even though I like to push the buckle).

For a real mechanical advantage, you could put a screwdriver into the slot at the end of the buckle and push on the screwdriver...although this is likely to damage the buckle :)
 
That definitely makes sense, although I don't believe I have misinterpreted anything.

When I close my buckle I put the base of my palm on the end of the buckle (actually on the strap as it is fed through the final slot) and push. I suppose I am not exactly on the end like the strap is, but I think a centimeter of difference hardly results in a mechanical advantage worth considering.

Gotcha. I've never seen anyone actually push from the tip. Even I use my palm over the whole face of it when I don't pull the strap. As for the centimeter making a difference, it might in terms of percentage. If your moment arm goes from 2cm to 3cm, you get a big difference. Assuming a normal cam is ~10cm tall, it makes a slight difference....but not as noticeable as what I had been thinking, you're right. If the technique used is to push from the "tip" of the buckle, then I think that other "techniques" are at fault, like the band being too loosely placed in the buckle. This could be remedied by the maneuver akimbo posted a video of (or a few others, I'm sure).

As for misunderstanding the physics, I apologize. Most people don't take into account the location of the force. My assumption was due to how I secure the camband, I shouldn't have assumed.

On that topic, someone was complaining that they couldn't apply any torque to their application despite using a cheater bar. When I checked, they were on the standard handle and thought the WEIGHT of the cheater bar was supposed to help. I explained torque. I got quickly corrected and told the moment arm was HUGE because the (completely unused) cheater bar was hanging there.
 
https://www.shearwater.com/products/perdix-ai/

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