Hi,
Has anybody any experience of the swimming pool bulkheads manufactured by Stark? Most of their production appears to have been installed in the US, so I haven't come across them before.
I have an existing one to certify for competition use : the pool in which it is installed has just been fully refurbished and, inevitably there is a major national level competition scheduled for the week after the recertification; little or no time for any adjustments.
From the manufacturer's website I understand that the bulkhead is a one-piece GRP moulding and looking at the design it should be much stiffer than the usual prefabricated types of bulkhead.
The pool where it is installed is trying to get both a 50 metre long course and two 25 metre short courses using the bulkhead, so anything more than minimal flexure is going to cause a problem.
It would be nice to be prewarned before I go there on Saturday about any past problems anybody has had with flexure of a Stark bulkhead under the lane rope tensions.
Thanks for any help forthcoming.
I just got back from the pool where I have touched the bulkhead countless times over the past 20 plus years, but it is not a Stark bulkhead. After reading their website a little I wish it was, they really make their product sound fantastic.
Seems like you would measure it in both positions both under tension and free standing.
As a swimmer I do not think the lane lines will pull enough to flex the bulkhead, but I could be wrong. Some bulkheads bounce a bit and it makes a cool noise when you push off.
Do you measure the center line of each lane in the process of certifying it or at greater frequency?
I staked a track one time and had to return to the field to re-measure because a specialty athletic surveyor had called the P.T. out by a couple hundredths.
I was asking about the Stark made bulkheads because I hadn't seen any before. Most of the bulkheads consist of multiple sections which are bolted together - easier to install for indoor pools. Some of these flex significantly and the designs have been significantly changed over the last couple of years as this problem has been highlighted.
For the London Olympics the bulkhead originally had a flex of over 25mm. at the centre. For the actual games we solved the problem by bolting it back to the rear wall of the pool. Subsequently a lot of stiffening work was carried out and it now (just) meets the requirement.
I've just completed certification on another pool which uses the revised design of that bulkhead. The flex is down to about 10mm., but given that the outer two lanes are not used for high level competition (these are 25m. wide bulkheads) lanes 1-8 are OK.
I must admit that when I first investigated I was very surprised at how much the lane ropes can deflect the bulkhead, although one problem is that many pools have no idea of how much (or little) tension they should be applying to the ropes.
Measurements are taken at 9 per lane over the full face of the touchpads. There is a PDF document on my website giving a full analysis of problem areas
www.SCSsurvey.co.uk/downloads/go5a.pdf
Nominal tolerances are very tight - half the problem is timing companies who push claims for timing to millionths of a second, when realistically 1/100th should really be the limit in any sport. Just accept that occasionally two athletes are so close in performance that there is a tie!
Interesting stuff.
Hearing about the touch pads reminds me of doing age group competition as a kid. The touchpads were about an inch thick and not very sensitive. Nothing like that sinking feeling of looking up at the clock to see how you did and see it still running because the pad was not triggered!
The pads are supposed to respond to a 2kg. load (so as to avoid accidental recording due to water wave), but as you have found out this can result in occasional non-touches occurring.
At least one manufacturer has now introduced an indicator light onto the pad, which lights up when a touch is registered. Not ideal, but at least that gives an opportunity to whack the pad if the first touch failed to register.
It'll be nice when all manufacturers adopt a similar solution. It's real fun trying to exert 2kg. pressure at the bottom end of a spirit level which is 80cm. under water.
By the way, some pads have little compression before the sensing load is reached, others will compress by up to 2mm. (which on a 1500m. race lengthens the effective course by 60mm.)
Yup, she's a Stark
Checked out the bulkhead during my set today and it says Stark on the top. I eyeballed down the top face and it looked like there may be 3-10 mm deformation but it is hard to tell if that extends to the waterline and while I have some trust in my eye I know that appearances can be deceiving.
Seems like a pretty rigid assembly but I could certainly see it twisting a bit after all.
Funny, chatting with a dude in England about measuring a swimming pool accessory manufactured in Arlington WA.
Yup, she's a Stark
Now I've measured one I'm quite impressed by the Stark bulkhead. Very little distortion under the lane rope tension. I guess the reason that most of their production has been limited to installations in the US is because one peice bulkheads 25 metres long need wide open spaces to intall them - not a problem in parts of the world which have open air pools or plenty of land to build on - rather more difficult where land is at a premium and there is rarely lots of spare room to enable such a beast to be threaded through the walls and into position.
After much messing about the pool was certified (so Commonwealth Games can be held this summer!!)
Couldn't get the architects dream of 50 metres AND two 25 metres either side of the bulkhead. I'm not sure if that "bright" idea happens on the west side of the pond but too many European locations are trying to do it. Unfortunately 50m +10mmx2 touchpads doesn't equal 2x (25m +10x2 touchpads) and although there is a little bit of tolerance you can build in between the bulkhead and the far end pool wall, its a bit like trying to apply particle accelerator tolerances to building work.
Still, it all makes work for the surveyor.
