Golf course maintenance is a never-ending task, with daily, weekly, monthly and annual programs needed to create desired playing conditions. However, can you name a routine task that is never ending, does damage to mowers, makes mechanics unhappy, and can greatly impact playing conditions in several ways? How about removing stones/rocks from bunkers?
Time consuming and never ending is only half of this issue, but the only time that removal is effective is when the sand is dry. What about the majority of the time when the sand is too moist and does not allow for effective cleaning?
The problem with wet sand is that the bridging among sand particles is stronger than the particles simply falling to the ground through a screen. In every type of manual or machine-powered unit, vibrating the sand does little to actually move the sand downward. What is needed is an up-and-down shaking motion to be more effective. Although humans can shake a rake or a small screen approximately three times per second, this is not enough to move wet sand through a screen. However, when this rate is increased to 30 times per second, the task of moving sand through a ¼” screen when it is wet can be accomplished. This was viewed at Chambers Bay, site of the 2015 US Open, where this former gravel/sand pit has the tremendous rock issue.
The unit tested is a lightweight, three pound rake with a lithium battery for power. The end of the rake shakes in an up-and-down motion at variably controlled speeds, allowing rocks to remain on the screen while sand filters through the screen. It was used successfully on the bunker edges with wet sand, while also removing fescue seedstalks and fir/pine needles on other golf courses. Once the stones have been removed, the rake very effectively smoothes the sand.
While this unit currently is not available for golf courses (it can be viewed at www.shakenrake.com and will be at the 2011 GIS in Orlando), it has been used for several years to clean horse stalls, where slightly larger “objects” need to be cleaned from horse stalls. Rocks in bunkers may not be equivalent to what horses leave behind, but tell that to a golfer the next time a stone affects their ball roll. Better yet, tell it to the mechanic…I dare you!
Source: Larry Gilhuly, lgilhuly@usga.org.