This Derrick, still standing in central Utah in 2005, is a very well preserved example of the central pole model. Note that
the central pole was free to turn so loads could be swung off the wagon and over to the haystack.
This hay derrick may not still be standing, since the picture was obviously taken long before the year 2000. However, it is
a very good illustration of the inverted "V Frame" type where the main boom pole was mounted below the supporting
inverted V frame. This derrick type had more limited mobility in the swing arc of the boom because of the restrictions of
the V frame it was mounted on. However, this type of derrick was stronger than the models that used a single pole to support
Picture courtesy Leon Pitman.