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Search and Recovery

Knowledge Review - Part 1

A recreational search and recovery diver:

  • recovers only small to medium size objects
  • profit or employment is not primary goal

Six potential hazards of search and recovery diving include:

  • sharp objects and debris
  • entanglement
  • low visibility
  • currents
  • falling objects
  • boat traffic

Five general steps in planning a search and recovery dive are:

  • define the dive objective
  • collect and analyze all available information
  • select a diving mode: snorkel or scuba
  • choose a dive buddy or team
  • briefing everyone involved

Use an expanded square search pattern or a U search patter when:

  • you only have a compass
  • varied topographies
  • large search areas
  • wallet-sized objects or larger

Use a circular rope search pattern when:

  • item is small in a small area
  • item is larger in current or surge
  • bottom is flat and free of obstructions
  • you have a line reel

Execute a circular roper search pattern by:

  • anchor diver anchoring line at center of search area
  • search diver takes taut line and swims in circle
  • after revolution release more line

You should never use your BCD for lifting objects because it could result in a runaway ascent.

The use of a lift bag becomes mandatory with anything over 10 pounds.

Three reasons why commercially-made lift bags should be used for recovering underwater objects:

  • made from heavy duty material designed for lifting
  • have dump valve systems
  • have convenient rigging

Procedure for controlling, rigging, and lifting an object using a lift bag:

  • secure a marker buoy and the lift bag to the object
  • check rigging
  • inflate the bag slowly in small bursts, pulling up between bursts, until it hovers
  • swim the bag and object horizontally (if necessary)
  • begin swimming up slowly with the bag
  • escort the bag venting to control ascent, or allow it to ascend independently

Alternate second stage or an accessory inflater are the only air sources you should use for filling a lift bag.

Knowledge Review - Part 2

Procedure for a jackstay search pattern:

  • use when searching for small object in large, relatively flat area with moderate current
  • establish baseline along search area
  • both divers start at edge of search area at one end of base line
  • Diver 1 swims search rope out perpendicular to baseline, searching
  • Diver 2 remains in place anchoring other end
  • Diver 1 reaches end of line and pulls it tight, then takes the end and swims toward unsearched area a short distance based on visibility and required overlap
  • Diver 1 anchors the end and swims back along the search rope back to Diver 2, searching
  • reunited, both divers move forward until search rope is perpendicular with baseline
  • repeat

Procedure for snorkeler led search pattern:

  • use with one or more divers over a relatively large pattern looking for a relatively large object
  • establish search area with anchored buoys or landmarks at four corners
  • snorkeler swims the pattern
  • divers swim in a V pattern with leader holding line

Procedure for semicircular search pattern:

  • use over bottoms that are flat and obstruction free and in current you can swim against
  • select a compass heading that takes search in straight line through search area
  • diver 1 holds search line
  • diver 2 swims with other end along the determined compass heading until it's taut
  • if divers cannot see each other, then make search line shorter
  • diver 2 becomes anchor diver
  • diver 1 becomes search diver
  • search diver swims half circle until realigning with the heading
  • anchor diver watches and signals when search diver reaches that point
  • divers switch roles
  • when they reach end of search area then searching diver makes full circle, switching direction
  • if object is not found, then establish another line overlapping original one

Procedure for shore walk search pattern:

  • use when searching a large area along shore, with one or many divers, and a tender on shore
  • tender holds search line and walks along shore
  • divers start at deepest point away from shore
  • divers hold line taut while swimming and search perpendicular from shore
  • when divers they reach end of search area, tender signals and takes up line
  • divers reverse direction
  • repeat until at shallow depth

Bottom topography and water movement can affect a search by:

  • dictating what search techniques you can use due to obstacles or current
  • influencing whether water motion can carry away object or bury it

Professional search and recovery differs from recreational in that:

  • it is for profit and/or employment
  • requires professional and ongoing training
  • may use sophisticated equipment
  • may be subject to labor/work regulations

Pinpoint a fix on a submerged object while at the surface over it by:

  • staying where you are
  • selecting two inline permanent landmarks on shore
  • rotating between 60 and 120 degrees
  • selecting another two inline landmarks
  • documenting information

Relocate an object using a known fix by:

  • swimming to general area
  • align with one set of landmarks
  • swim along line until other set of fixes align
  • descend and search

Three commonly used knots for search and recovery are:

  • bowline: attaching rigging to lift bag and object
  • sheet bend: joining two lines together
  • two half-hitches: tie line around an object

Prepare for tying knots underwater by:

  • learning to tie the knot
  • practicing tying knots with gloves
  • practicing tying knots with gloves and with eyes closed