Expanding Box? Uh?

Why call myself ‘Expanding Box’?  Good question…


I’ve been proud to be involved with the Swanage Lifeboat crew for the whole of this century and have often found myself comparing what happens at ‘work’ with what happens at sea.

There should be a lot of similarities – both work in teams, both are organised in a hierarchy, both train to perform specific roles.  But there are obvious differences too.

But none of that explains ‘Expanding Box’, so let’s get to the point.  Briefly then….one of the search patterns we can employ at sea is called an ‘expanding square’ search.  I’m pretty sure we used to call it an ‘expanding box’ search. I know the cognoscenti will shudder, but I prefer it (and let’s face it, neither ‘box’ nor ‘square’ are really correct…).

An Expanded Square search pattern plot

The pattern is simple, spiralling out from a datum point covering an increasing area as time passes.  But plotting the route like this onto a chart is misleading – we don’t drive the boat along the red line and recreate the plan in reality.  Why not?  Because what we’re looking for doesn’t stay where it’s put – the whole seascape is moving with tide, wave action and wind.  So what we actually execute looks more like this:


Update 14th Feb.  Ran an expanding Square on exercise last 
night about 5 miles south of Anvil Point.  
This is the resultant track showing how the strong westerly 
wind was pushing us to the east.  
But that's OK, what we're looking for is moving too...

The point is that on paper the pattern, or plan, is clear and obvious but the execution of the pattern is affected by all sorts of factors which results in a much more complex looking picture, often impossible to predict.  

Sound familiar?  Recognising the reality, understanding the factors involved and making well-informed decisions as a result is what I can help you with.

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