10
CONCEPTS
1–CONCEPTS
BROCK’S BACKYARD IS PERFECT FOR A ZIP LINE. HE ORDERED A 200-FT LINE AND IN ORDER TO INSTALL
IT, HE NEEDS TO FIGURE OUT WHERE TO ANCHOR THE CABLE ON EACH OF HIS TWO TREES. SO HERE’S
WHAT HE DID. FIRST, BROCK READ THROUGH THE ENTIRE MANUAL THE EVENING BEFORE HE PLANNED
ON SETTING UP HIS ZIP LINE.
THE NEXT DAY HE PACED OFF THE DISTANCE TO MAKE SURE HE KNOWS THE EXACT DISTANCE.
THE DISTANCE IS 180-FT. HE FILLS IN BOX 1 = 180
NEXT, HE FIGURED OUT THE AMOUNT OF SLOPE HE WILL NEED. SINCE HE PURCHASED A ZIP
LINE THAT ONLY INCLUDED A STOP BLOCK, HIS CALCULATIONS WILL BE FOR A 3% SLOPE. WHIPPING
OUT HIS SMART PHONE HE MULTIPLIES 180 X 0.03 AND GETS 5.4, WHICH HE ROUNDS TO THE NEAREST
WHOLE NUMBER AND ENTERS 5 IN BOX 2.
USING HIS LENGTH OF 180 FROM BOX 1 HE MULTIPLIES IT BY 0.02. HIS ANSWER WAS 3.6
WHICH HE ROUNDS TO THE NEAREST WHOLE NUMBER 4 AND ENTERS IT INTO BOX 3.
TO FIGURE OUT HOW MUCH HIS YARD ELEVATION CHANGE IS BETWEEN THE TWO ANCHOR
POINTS HE ORDERED A SIGHT LEVEL. HE IS SIX FEET TALL, SO HE PENCILS 6 IN BOX 4B, NEXT HE
LOOKS THROUGH THE SITE LEVEL UNTIL THE BUBBLE LINES UP WITH THE CENTER CROSSHAIRS ON THE
END ANCHOR TREE. THERE HAPPENS TO BE A NICE BRANCH THAT HE CAN IDENTIFY EASILY WHICH WILL
BE WHAT HE WILL USE FOR A MARK. HE HIKES TO THE END ANCHOR TREE, SETS A LADDER AGAINST THE
TREE AND CLIMBS UP THE LADDER WITH A TAPE MEASURE. HE MEASURES FROM THE GROUND TO HIS
MARK, WHICH WAS A NICE BRANCH. THE TAPE MEASURES 14-FT. HE PENCILS IN 14 IN BOX 4A AND
THEN CALCULATES WHAT BOX 4C IS. [14 - 6 = 8] AND HE PENCILS 8 IN BOX 4C.
JUST FOR THE FUN OF DOUBLE CHECKING HIS FIGURES, HE DOWNLOADS AN ALTIMETER APP ON HIS
SMART PHONE. STANDING AT THE BASE OF THE START ANCHOR TREE HE TAKES THE FIRST MEASURE-
MENT WHICH IS 1743 FT. FROM SEA LEVEL. HE JOTS DOWN THAT NUMBER WHILE STRIDING OVER TO
THE END ANCHOR TREE. TAKING ANOTHER MEASUREMENT ON HIS APP AT THE BASE OF THE END AN-
CHOR TREE, THE READING SHOWS 1735 FT. FROM SEA LEVEL WHICH HE PENCILS BELOW THE FIRST
FIGURE. CALCULATING THE DIFFERENCE BETWEEN THESE TWO MEASUREMENTS WILL BE THE
ELEVATION CHANGE BETWEEN HIS TWO ANCHOR POINTS AND THIS CAN BE ENTERED INTO BOX 4C.
WITH ALL OF HIS PHYSICAL MEASUREMENTS COMPLETED, HE SITS DOWN ON HIS BACKYARD DECK AND
FILLS OUT THE REST OF HIS WORKSHEET.
TO CALCULATE HIS ENDING ANCHOR HEIGHT [BOX 3 + 7 FEET = BOX 5]
4 + 7 FEET = 11 FOR THE END ANCHOR HEIGHT.
TO CALCULATE HIS STARTING ANCHOR HEIGHT [BOX 2 + BOX 5] – [BOX 4C ] = [BOX 6 ]
[5 + 11 = 16]– [8] = 8 FOR THE START ANCHOR HEIGHT.
NOW BROCK IS READY TO MOVE ON TO HIS NEXT STEP.
INSTALLATION EXAMPLE
GO TO NEXT STEPS
CABLE
INSTALLATION
2
BOX 2
BOX 1
BOX 3
BOX 4
BOX 5
BOX 6
1743 ft. - 1735 ft. = 8ft.