The use of portable cross-country fences had increased greatly in the last few years. There are many advantages to the course designer in deploying obstacles that can be used in many different locations, on a course and even at several event sites many miles apart.
The advent of rough terrain forklifts that are capable of lifting and moving a complete obstacle in one piece has facilitated this increased use. Formerly any fence that had to be moved had to be built in sections small enough to be manhandled.
When building portables try to incorporate forklift ˜pockets’ into the fence to allow the tines of the forklift to go into the structure of the fence rather than having to push them into the ground to pick the fence up and then digging up two large divots of turf. If the fence can be picked up on tines one operator can move fences on their own with little risk of damaging the obstacle in the process.
Rough terrain forklifts are extremely heavy machines; take great care when using them on anything but the driest and hardest of ground. Do not turn the steering of rear or four wheel steer machines or ordinary tractors with loaders, when standing still, as this will cut the turf with the tyres. Articulated machines are the most user friendly, as the wheels move forwards and backwards when the steering is turned and the tines move sideways which is an added benefit.
There is more than one downside to portable obstacles. A fence built at the maximum height for a class on the flat concrete in a workshop will be too high when sited on the slightest rising ground, due to the rule that fences must be measured from the point where a horse takes off, rather than straight up and down. Therefore they should always be built slightly lower than maximum height to allow for this. It is usually possible to raise a fence up on wooden blocks if it is too low but it is lot of work to dig it in if it is too high and this defeats the object of having a time saving construction.
Portable fences tend to look odd when placed on steeply sloping sideways ground.
The anchoring of all of these types of fences is of paramount importance. There is nothing more dangerous than half a ton of fence tipping over when hit by a horse. Severe injuries may be caused to both horse and rider if this should occur.
The number and strength of the anchors used for retaining fences will vary according to the profile. The base spread is critical. This should always be more than the height of the fence. Anything with a base less than the height of the fence should be fixed using proper fencing posts driven into the ground with a tractor mounted post driver and then attached to the fence with ‘Spax’ or ˜Timberlok’ type screws.
It is often possible to increase the base of a fence with legs that extend out on the landing side, as with portable steeplechase fences. Up to 400mm, 16” is safe as a horse will always land further away than this. These legs will help to reduce the number and size of the anchors required
A fence with a low height and large base spread, if it is fairly heavy, could be secured simply with half round or square sawn fencing stakes driven into the ground back and front by hand with a fencing maul of large sledge hammer. These should also be attached to the fence with Spax or Timberloks.
There is now a purpose designed steel anchor available, called the Spirafix Ground Anchor. This is in the form of a spiral screw which is hammered into the ground through a special bracket screwed securely to the base of the fence. There are two lengths depending on the soil type. Long for sandy soils and shorter for stony soils where it is hard to drive them in. The clever part of the design is that they can be removed very simply by screwing them out with a spanner in a few seconds. These are expensive to purchase in the first place but as they save a great deal of time and can be used over and over again they pay for themselves in the long run.
Fences with a reasonable base can be fixed with anchors at the front only narrower fences will need them at the back as well.
If in doubt as to how to anchor a fence, take advice from an experienced course builder or BE Technical Adviser.
Downloads & Links
Clarification on the Securing Down of Portable Cross Country Fenceswww.spirafix.com - Spirafix Ground Anchors