WHISPER 100/WHISPER 200 24 Foot Tower Manual
Document #0026 REV E
SOUTHWEST WINDPOWER
5/20/05
9
Step 5: Guy Wire Anchor Installation
There are four types of anchors that are most commonly used with our towers; screw in “Auger”
type anchors, hammer driven “duckbill” anchors, cast concrete anchors and expansion bolts (for use
only in solid rock).
What anchor should be used depends on the soil type that the anchors will
be placed in.
See the following table for our suggestions:
Soil Type
Sand
Loose Gravel
Loam
Clay
Rocky Soil
Gravely Soil
Solid (Soft) Rock
Solid (Hard) Rock
Recommended Anchor
Concrete
Concrete
Auger
Duckbill
Duckbill
Auger or Duckbill
Large, Long Expansion Bolt
Smaller Expansion Bolt
Alternatives
None
None
Duckbill, Concrete
Auger, Concrete
Concrete
Concrete
Large Eye Bolt + Cement
None
The loads on a single anchor can exceed 1,500 lb. in a 100-mph gale. Make sure that the anchors
chosen can withstand at least this much force or the tower will have to be lowered during storms.
Augers and Duckbill anchors are frequently available at mobile home supply stores. Augers are
also available the dealer where your turbine was purchased or from SWWP. Expansion bolts for
anchoring in solid rock can be purchased at most hardware stores.
Augers:
If the soil conditions make their use feasible, augers are the simplest anchors to install.
Augers screw into the ground using either a piece of wood, pipe or rod as a “cheater bar”. If a
mistake is made or if the tower must be removed an auger can be “unscrewed” out of the ground
and reused. They depend on the soil holding together for their strength are not suitable for sand or
loose gravel. If the soil is rocky or clay-like you may have difficulty screwing them in.
An auger is usually installed by screwing it straight into the ground a few turns to get it started and
then tilting it to the desired angle once it is into the ground a few inches. A substantial downward
pressure is usually necessary to get an auger started. Screw the augers in as far as possible for the
greatest strength.
