Stake Boom

**oldgringo** · 06-10-2011, 11:56

Originally Posted by Alamosa

Disclaimer: I am not a mechanical engineer and the statements made represent my opinions and are based on my observations and deduction. I don’t claim that this is safe for any particular purpose.

This entry is pretty long, so I am breaking it into multiple posts for the individual sections.

Issue: Stakes are used to anchor an item (tarp, canopy, etc.) to the ground. When the stake is driven into the ground and the cord is attached at the head, it generates an unbalanced force on the stake. This produces a pivoting action on the stake when the cord is tensioned. The effect is that a compressive force is applied to the ground in front of the stake above the pivot point and to the ground behind the stake below the pivot point.

The result is that the holding power of the stake is reduced from its full length to the equivalent holding power of two much shorter stakes which are applying their pressure to a smaller areas.

T he more the stake is pulled toward vertical, the more the hole it was driven into is expanded providing less constriction on the stake and the easier it is to pull out of the ground. In addition, as the stake is pulled toward vertical, it is subjected to a much greater vertical force trying to pull it out of the ground.

In short, the worse it gets, the worse it gets.

Not that it changes anything, but I think the fulcrum is all the way at the bottom of the stake. But then, I'm not a ME, either.

**Knotty** · 06-10-2011, 15:32

I am an ME by degree and am still puzzled as to which model correctly represents the situation. All those years in sales have dumbed me down.

**GrayDog** · 06-10-2011, 15:55

I'm not an engineer and don't play one on TV but...

If you could come up with a titanium or aluminum tube. You could use it with an ultralight stake like

so the whole thing comes apart for packing while retaining the surface area resistance of the V shaped stake.

There are plastic versions available but I would question their strength vs weight.

**shumway** · 06-10-2011, 16:12

I've seen this idea before. The stake was made of steel bar, bent like you say, and was huge if I remember correctly. I think it was used for one of those circus sized tents. I can't find an image on Google though.

**Gqgeek81** · 06-10-2011, 17:23

I sort of think the fulcrum point is at ground level?

If the hole in the boom produces a weak point consider making something shaped a bit like an F. Imagine for example a pipe wrench laid on the ground and pushed over so the stake comes up between the jaws. If you were to then pull up on the end of the handle it would transfer the torque to the stake. A lot of Tree Stands also work like this and some weed pullers and post removers for tractors.

**gmcttr** · 06-10-2011, 18:40

For the sake of argument, the fulcrum point will be at the highest point that the soil has the strength to support the stake and not allow it to "cut in" any farther. At least that's my story and I'm sticking to it.

**Catavarie** · 06-10-2011, 19:20

So why not just use a decent sized rock or log placed on the line directly in front of the stake, therefore changing the direction of the force on the stake from vertical to horizontal? This would alter the direction of the stake on the ground as the fulcrum would move up to ground level and therefore the ground behind the stake would be significantly greater (roughly tripled assuming 45* angle) so a much greater force would be required to cause the stake to launch on it's own.

It is truly UL as you don't have to carry the rock or log with you, simply pick it up at the campsite. Also this has been done for years with success by many people. All you reall need is an extra 6 inches of guy line.

**bigred72** · 06-10-2011, 19:21

Check these out. A little pricey, but hanging in sandy and snowy areas, these are the best. I use the MSR ground stakes in the same manner.

http://www.toughstake.com/

http://www.youtube.com/watch?v=ihjQWZe86gg

**Browny** · 06-11-2011, 00:02

Freaky timing, I just made some of these at work.

5mm Dia. High Tensile Stainless Steel

Depending how they go, I may lengthen the top as per op.

For me, I think they will pack ok in a custom sack, sort of like a sock with the ankle bend. All nested together.

**bigred72** · 06-11-2011, 09:32

Originally Posted by Browny

Freaky timing, I just made some of these at work.

5mm Dia. High Tensile Stainless Steel

Depending how they go, I may lengthen the top as per op.

For me, I think they will pack ok in a custom sack, sort of like a sock with the ankle bend. All nested together.

Now that is Slick!!!