TRAVIS COUNTY DIVE TEAM
2-PERSON "Z" SEARCH
Description
The 2-person "Z" pattern covers a large rectangular area with a
small number of divers.
It takes longer to set up than a circle pattern, but it moves quickly
once it is set up.
The "Z" pattern uses two search buoys with a search line connected
between their anchors.
Start with the search line marking one end of the search area.
The search team starts at one anchor and searches along the line.
When they reach the other anchor, they move that anchor a few feet
perpendicular to the search line, then search back along the line
to the first anchor.
When they reach the first anchor, they move it in the same direction
as the other anchor, then search back along the line.
This pattern moves the two anchors along the sides of the search area
and sweeps the search line between them.
It is similar to the "Jackstay" pattern except that it does not involve
setting the stay lines along the sides of the pattern.
JOB DESCRIPTIONS
One SWEEP and one POINT
SWEEP - JOB DESCRIPTION:
- In charge of the team.
- Moves the buoys and searches along the search line.
- Responsible for the integrity of the patten.
POINT - JOB DESCRIPTION:
- Stays in contact with the Sweep and searches ahead of the search line.
- Responsible for all search activity.
The POINT works in undisturbed water ahead of the search line.
Finding and Recovering the Search Target:
There is no "Found-the-Target" signalling required.
The entire team is together at all times.
Operating the Z Pattern
Starting the Pattern
This is the tricky part. It takes practice.
- Connect the search line between the two anchors at the surface.
- Before lowering the anchors, position the starting buoy
where you want one corner of the planned search area.
Position the other buoy at the right heading along one end of the search
area, but do not pull the search line taut at the surface.
- Before lowering the anchors, both divers should set their compass
markers for the heading between the two buoys at the surface.
- Lower both buoys' anchors slowly, at the same time, with the search
line connected between them.
You left some slack between the anchors, so they should not drag each
other out of position.
- The divers descend on the first buoy, swim the search line to the
second anchor, and then reposition the second anchor.
Set the right compass heading and pull the line taut.
Tactics
- This pattern works best with two divers.
A third sweep will not let the pattern go any faster.
If you have extra manpower, set up more than one pattern.
- If you start two patterns at opposite ends of the planned search
area, moving toward each other, they will cover the whole area
when they come together.
- If you start two patterns back-to-back across the center of your
planned search area, moving away from each other, you will cover
the middle of the area first.
- The Z pattern is equipment intensive.
You need one buoy per working diver.
And both buoys on one pattern should have the same kind of anchor.
- This pattern inherently bears off at a slight angle away from
the anchor that moves first.
There are two ways to counteract that:
- The SWEEP should make the first anchor movement about half of
the visibility distance.
- When you set the buoys, they won't be lined up exactly right.
Start from the buoy that you want to rotate the pattern toward.
- Run the pattern with the same divers acting as SWEEP and POINT
in both directions.
It is important for the same diver to move both buoys so both
ends move at the same speed.
- When the SWEEP moves each buoy, the POINT should move up the anchor
line a foot or two to stay out of the way.
Then the SWEEP gets in position to start.
Finally the POINT moves back down and beside the SWEEP to start
the pattern moving again.
- The SWEEP should pull the search line taut while moving the anchor.
That keeps the pattern at full width.
If you drag each anchor toward the other one a little,
it will not hurt the pattern.
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