Building a High School Shot Put Sector
Geoff Emerson – Throws Coach – Myers Park High School, Charlotte NC
This summer, we set out to solve a problem we've had
with our shot sector for a number of years. Because our
sector is almost perfectly level - which is normally
desirable - it retained water after a heavy rain. This
caused us to miss too many days of practice during
otherwise acceptable weather.
An Internet search of construction methods didn’t yield
very much, so this article is being written in the hope that
it will help someone else. I'm not suggesting this is the
best way or the only way, it's just how we did it.
Our design was to create a ‘shower pan’; that is, the periphery of the sector was excavated to about 4"
and sloped down to about 7" in the center of the sector. In the center we dug a hole or ‘retention well’
about 4' wide by 10' long by 2' deep. The idea is that water runs down the slope and collects in the
gravel filled well where it eventually drains, but keeps the material above dry.
We began by excavating to a depth of 4-7" in a shape slightly wider than a 34.92 degree sector. This
extra width gave us room to work with the lumber that formed our sector line barrier. We chose a
distance of 60' as a trade-off between material costs and the throws we're likely to have. The area
beyond is grass, so we can still accommodate longer throws. The dimensions of the retention well were
an educated guess, but have worked out so far. We elected to have the excavation done with a machine
vs. manually, which added cost, but saved considerable time and also gave us a more precise shower
pan.
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After creating the pan we filled the retention well with 5
tons of a material called 6/7 stone, which is small gravel.
Then we covered all but the well with a material called
'soil separator' which is designed to stop water from
penetrating, allowing it to run into the retention well.
When placing the soil separator, it should be overlapped
like roof shingles so that water running down the pan
(periphery to center) does not run under the material.
Although some people use nails or stakes to hold the soil
separator in place, we found that the 4 x 6 lumber for the
sector line barrier worked fine.
We then laid 4 x 6 lumber on the sector lines, oriented 4"
across and 6" down. We drilled three 1/2” holes in each 10'
section and anchored them with 2' rebar (also 1/2”). We
used a sledge hammer to drive the rebar flush with the
lumber (the hole and the rebar are covered with PVC
boards in a later step). We considered positioning the
lumber outside of the sector which would slightly reduce
hits from errant shots but would also require us to
continue to paint sector lines. We also thought having the
border be the actual sector line looked better.
The arc of the 60' back line was made by using scrap (less
expensive) synthetic decking installed on its side and held
in place with rebar.
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Next, we filled the sector with a material that the local stone yard calls 'washed screenings'. I've also
heard it called granite dust. It has a fine enough consistency not to chew up the shots, but compacts
better than sand so it’s firm to walk on. To achieve a minimum depth of 4" out to 60’ required
approximately 32 tons of screenings. Before adding the screenings, we placed conventional landscape
fabric from Home Depot over the retention well, so as to allow water to penetrate, but not the
screenings.
Once the screenings were spread, the next step was to
install our actual sector lines on top of the 4 x 6's. The
sector lines are made from 1 x 2 x 8' PVC board. We
chose this over wood for maintenance reasons as they
would never need to be painted. The boards were
fastened with deck screws to exactly line up with the
34.92 sector. By screwing the PVC in using 8’ sections, we
will be able to remove and replace them should they
become too banged up.
Cost - the total cost was about $2600. Major expenditures were:
• Stone– 32 tons of screenings & 5 tons of 6/7 stone – $1075 (including $285 delivery)
• Rental of bobcat and operator for a day – $750
• Landscape lumber ($220) and soil separator fabric ($220)
• White PVC boards ($160) and miscellaneous wood and hardware.
There are opportunities to reduce cost with additional labor (digging vs. bobcat), less expensive
materials or reducing the sector dimensions (e.g. 50’ vs. 60’). Our sector was paid for, both financially
and with a lot of 'sweat equity' by parent volunteers, many of our throwers and our team’s coaching
staff.
The Final Result
We've only been using the finished sector for about a month, but so far it has worked well. We didn't
take any specific steps to compact the screenings, such as rolling them or using a plate tamper, but they
are pretty firm to walk on already and hopefully with additional rain and foot traffic, they'll firm up a
little more. A few weeks back, we had a big storm (1" of rain in one hour), and while the sector did have
puddles in it immediately after, it drained quickly and within a few hours was bone dry. So we hope we
accomplished our goal of having a drier sector.
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