Comments on: About the Bias

By: larry

larry — Tue, 10 Jan 2012 13:36:00 +0000

Hi,

Where can I purchase a set of the lowest bias bowels?

Thanks

Larry

By: Zena

Zena — Sat, 12 Nov 2011 16:45:52 +0000

I have just started playing bowls and am having difficulty deciding how to face my ball depending on the direction. Which side depicts the bias one way or another

By: Shogun

Shogun — Sun, 25 Sep 2011 01:54:43 +0000

Hi,
Just for an experiment I am interested in instrumenting a lawn balling bowl with a 9 DOF IMU package. This would allow me to track and display the trajectory, speed, direction, ‘wobble’ and path of a ball in real time on a computer screen. The IMU has three 3 axis sensors, an accelerometer, a gyro, and a magnetometer. The gyro maybe limited to 2000 degrees per second , which tranlates into about 5.5 revolutions per second. Can anyone tell me the range of ball release velocities when balling. (I may be limited to about 9.8 mph using a 5″ diameter ball?)

One could also use it to measure the ’speed’ of the green, the profile of the green observe the affect of bias etc.

regards

By: PHIL ROBINS

PHIL ROBINS — Wed, 13 Jul 2011 12:57:03 +0000

The important points to consider when choosing a bowl type (narrow or wide) assuming you have the correct size and weight are:-
The amount of bias a bowl has and the type of curve it takes.
The speed/s of greens you normally encounter i.e. grass, synthetic and carpet.
The position you normally play in a rink.
Remember when you use narrow bias bowls you have less tolerance with your weight (length of travel) than with a wider drawing bowl.
With the narrow drawing bowl you have more tolerance with your green (width) than with a wider drawing bowl.
On the slower greens you can get away with narrow bowls if you play at the ‘front end’, if your’e a ‘back end’ player you might be better off with a wider drawing bowl.
There is a strong body of opinion that some modern narrow bowls are more affected by the wind than their wider counterparts.
On the faster greens (15+ seconds) the ‘back end’ players prefer a narrow bowl because it has less or no hook at the end of it’s travel. This makes the ‘yard-on’ shot and it’s over draw weight deratives much easier to play.

By: Bill Huggins

Bill Huggins — Sun, 27 Feb 2011 13:36:57 +0000

How do you decide what weight,size and bias suits you?
I started with size 3 and wide bias and my son has bought me size 3 with a narrow bias.Both of which I was ok with but not consistent.
I see other players with various sizes with heavy added,how do you know which is right for you to get consistency.

By: Alan Glenny

Alan Glenny — Mon, 31 Jan 2011 18:52:23 +0000

In answer to Rob Buttrose’s query about bowl delivery direction, I have looked at Rod Cross’s piece and had e-mail ‘discussions’ with him.

What emerges from his work, amongst other things, is that to bowl to a given jack position, the angle of delivery (that’s the angle between the line between the mat and jack (centre line) and the initial direction of motion of the bowl) is constant regardless of the jack length.

So if you bowl narrow with reduced weight, the bowl will cross the centre line and end up short, and vice versa.

Arguments often arise about the statement ‘you need to give the bowl more green for a longer jack length.’ What Rod Cross’s maths shows is that for a constant mat position, the angle of delivery, therefore the ‘aimimg-point’ on the rear bank, is constant. True for a longer jack length the bowl will go further from the centre line.

However, with a varying mat position and fixed jack length, again the delivery angle is constant, but the required aiming point moves inwards towards the centre line as the mat is moved up the green. This confuses some bowlers.

I’m happy to explain this further if anyone is interested.

By: Peter

Peter — Thu, 16 Dec 2010 16:41:25 +0000

Keith’s response is a straight copy of a theoretical academic paper by Rod Cross published in August 1998 in the American Journal of Physics, for Physics Teachers.
The rules and regulations for master bowls are determined by Word Bowls Ltd. For more information you can visit their website.

By: Rob Buttrose

Rob Buttrose — Thu, 11 Nov 2010 04:33:40 +0000

Hi, basic question from a newbie for all you bowlers.

Given green conditions, wind, temperature and bowl bias how may paths will take a given bowl to the jack (or any desired location ?) Is it only one or range?
Suppose you find the combination of speed and angle that gives you the perfect path. Now , if you bowl a narrower angle than that of the perfect path, the bowl has to have less speed (because it is travelling a shorter distance) . Will it , however, curve off the line or can it curve less? Suppose on the other hand you bowl at a wider angle than the perfect path. In this case, you have to have more speed because it needs to travel further. Can it curve back enough or will it stay wide?

I’ve had a look at the above article by Cross. The answer may be in there somewhere, but I can’t find it. In any case, anyone who has bowled for a while (and has not been kidding themselves! ) will know the answer.

By: Alan Glenny

Alan Glenny — Sat, 30 Oct 2010 13:19:18 +0000

I’ve ‘read’ Keith’s entry on the motion of a bowl on the trajectory of a ball in lawn bowls by Rod Cross, Physics Department, University of Sydney, Sydney 2006, Australia.

I also have an interest in this area (please don’t tell me ‘to get a life’), I do have one.

Does anyone have access to the original article as the maths contained in it is somewhat garbled.

By: morris mccullagh

morris mccullagh — Mon, 16 Aug 2010 14:34:21 +0000

As a coach and keen mathematician I have always wanted to know the maths of the curve a bowls takes and so I found this exposition both interesting and bewildering. I wonder do manufacturers use mathematical formulae in order to determine the bias of a new bowl or is it hit and miss.