# Thread: 1 inch dip in the middle of the net

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## 1 inch dip in the middle of the net

why is this necessary?

2. it is physics. you cannot have no dip.

as the net has weight, to have no dip, it will require infinitely tight string to support it. or at least very very high tension string.

but most of the time the standard (poles) aren't that strong to support a very high tension so the rule allow for an inch dip.

3. I thought the dip was half an inch...

^Not necessary; unavoidable.

With the type of posts you see on TV it's impossible to get the net absolutely straight on top because the posts will fall inward - there's something like 100 kg holding them in place, but they'll tilt if the string gets tight enough. If I had my maths hat on I'd have a go at working out the minimum possible dip for the given catenary and tension, but it's only 10 am...

(The posts at our club are sunk into the floor, so we can get our nets basically straight i.e. eight of inch or less.)

4. the dip will not be unavoidable if the top of the net is made of a solid steel bar or rod running the across the width of the court... but it might hurt the racket if you accidentally whack it...

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Even if you had solid, high-strength steel posts (and thick steel cables to take the tension), there would still be a few mm of deflection. Plus, you'd have to have a tennis-net style crank to apply the tension.

My club doesn't have posts which fit into the floor, so an inch is about the best we can achieve before the posts (with additional weight) start to slip inwards.

However, did play at a club in Denmark. They had a turnbuckle tensing a steel cable. They could achieve such a high tension that you could sit on it! Didn't look comfortable or safe, so didn't try it myself!

6. Plus, you'd have to have a tennis-net style crank to apply the tension.
This made me think of Homer Simpson:

"Make sure the net is tight and springy..."

*dog is catapulted into a tree.

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why not make the top of the net rigid? like inserting a pole in there.

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I played in a church few times which has a court with two pillars as the pole!
so I tighten it and there is almost no dip

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