Floating Docks

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Floating Docks

Postby cortney_lofton » Sat Mar 19, 2005 11:41 pm

On March 16,2005 I received a call from the Big Bear Lake District expressing that the ice had melted and some of the docks had broke free and were floating to the center of the lake.

*Note that the mountain had been in a six year drought and has significantly impacted the lake by twenty feet. we estimated aprox 30% of the docks were not in use due to the low water level.

After this years visit of the pineapple express weather storm, the lake gained twelve feet. As a result the non used docks floated off their pipe ancors, leaving a 3 inch pipe standing from 4 to 10 feet from the surface. Thats aprox 400 poles around an 11 mile shore line, creating a very dangerous condition.

We have the month of April to complete the search and recovery before the boat season opens.
The visability is aprox 3-5 feet if the north westerlys down.

We rigged a barge with a Videoray,an Air jack,Lift boom and diver.
We charted the location on a map, of some of the existing docks along the shore line then using topo's we estimated where some of the docks would have been located during the drought season.

Is this like finding a needle in a hay stack or What?

Any Suggestions?
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Floating Docks

Postby scott_bentley » Mon Mar 21, 2005 7:05 pm

A sonar is going to be key to solving this. There are two methods to consider in deploying sonars on this job. One is to use a VideoRay-mounted scanning sonar. This will not be as useable for navigation, but will be more maneuverable in finding each pole. The second is a barge-mounted sonar, which would be more stable and could track the VideoRay and the poles. We've found that you need a pretty good sonar to track a VideoRay, and sometimes you need to add aluminum foil or something to increase its reflectivity when tracking on a scanning sonar.
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