Cutting a Wide SWATH

Impractical.  Inefficient.  Just plain difficult.

A lot of these terms came to mind when staring at the current state of Poolbot, and imagining trying to get it to cross a body of water larger than… well, a pool.  The most recent problems with getting long-range communications equipment mounted just compounded the negativity.

Then, an epiphany: why not have Poolbot carried by some other vehicle.  It could be simply dropped into position by a surface “carrier”, which needn’t submerge.  All the GPS, communications, solar charging, etc. equipment can be kept on the carrier, which would be more visible and more stable, with much more reliable communications. 

Having seen recent stories on the late, engineer-lamented Lockheed-designed US Navy experimental ship, Sea Shadow (IX-529, torn up for scrap in 2012), using a SWATH design for the carrier makes good sense.  Poolbot could be suspended under the main hull during surface transport, above the waterline.

This idea is brilliant.  So brilliant, in fact, that a NATO research group at Italy’s University of Genoa outlined a highly similar design… in 2010.

Nevertheless, despite a total lack of originality, a SWATH-based carrier for Poolbot is the new plan.  The NATO ASV design does not cover certain key details about deploying and recovering its AUV.  Nor are charging and comms covered.  To that end, here are a few specifics for Poolbot’s carrier:

  • solar panels mounted to the top and sides
  • “claw” under main hull for Poolbot, to keep AUV above the surface during transport
  • GPS, XBee, cellular antennas on carrier hull
  • at least one main-hull-mounted camera
  • batteries in main hull body
  • wireless communication (XBee) only with Poolbot – no wires for data!
  • wireless charging, if possible, for Poolbot (inductive charging pad under claw?)

All of this should allow both Poolbot and the carrier to carry out operations autonomously, indefinitely, without having to be opened up for anything other than serious drydock maintenance.  Even better, almost all of the original Poolbot plans and code can be kept unchanged.

Next post: dimensions and a mock-up…

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