Image of party barge, showing upper deck.
The Playhouse – History Reimagined
2023-Dec-29

Project Scope

DMS worked with our Client to develop a nearly unstoppable drone.  This little vessel traveled independently for months on end, performing sonar surveys and deploying survey buoys along the way.  Reliability was key for this vessel.  Other long range vessels may use sails and flimsy hulls.  But sometimes the wind doesn't blow where you want.  So our Client requested a fully powered design, chock full of redundancy.  This beauty came fully loaded:

  • Multiple redundant batteries.
  • Main engine alone can power all vessel systems.
  • Backup generator included.
  • Azimuthing retractable bow thruster, which also doubles as emergency propulsion
    • Bow thruster normally retracted, protected inside the hull.
  • Recessed keel coolers to protect engine cooling.
  • And many more little details . . .

 

Nearly Unsinkable

This was a small drone, operating on a big ocean.  We knew to expect ocean waves that easily swamped the vessel.  DMS prepared for the ship to face severe storms, with a host of stability features.

  • Full self-righting capability.  If a wave capsizes the drone, it will always roll back upright.
  • Operation with flooded mission bay.
    • The mission bay frequently deployed buoys from the stern.  A wave can flood the entire mission bay during this operation.
    • A flooded mission bay was just an inconvenience.  The drone remained afloat and operational.
    • Just activate bilge pumps to clear out the water, and keep operating.
  • The drone had sufficient righting energy to tackle moderate sized waves without capsize.
  • Full damage stability survival.  Flood any compartment of this drone, and it remained completely upright. 
  • Minimal roll motions.  Even in stormy conditions, the vessel showed minimal roll motions.  Small roll meant better sonar surveys.  Get your survey back sooner, with better data.

Everything about this vessel screamed survival.  It rose to the challenge of operating in normal to stormy conditions.  No more waiting for a sunny day to complete your survey.  And if the truly horrible storm blows in, just ride out the storm.  The drone survived many severe storm conditions.  With this drone ship, you no longer fear the storm. 

Cross the Pacific Ocean - TWICE!

Endurance and range were critical for this drone.  The ship deployed on long range endurance missions, going for months at a time.  Other designers may use a sail powered drone.  But sails only work when the wind blows where you want it.  Our Client required a fully engine driven vessel for independence. 

DMS carefully studied the vessel powering.  We did better than just throwing in a big engine.  We created an efficient drone.  She had the power to achieve over 7 knots when needed.  But at slower speeds, her efficiency really shined.  At peak efficiency, we saw the real power of this drone:

  • A mission operating time of over 80 days.  Over 2 months uninterrupted!
  • A maximum travel range over 9500 NM.  That's enough to cross from the USA to South Korea and back, on a single tank of fuel!

No reliance on the wind.  Undeterred by large ocean waves.  Almost unrestricted range and endurance.  This drone goes anywhere!

Return on Investment

Seakeeping Prediction

Drone motions were critical for this design.  The sonar worked best pointed vertically down.  With a rocking vessel, that reduced sonar quality, leading to repeat runs, less area surveyed, and longer survey time.  DMS predicted the roll motions for rough sea conditions, using a seakeeping analysis.  Vessel roll remained small, allowing continued operation, even in rough seas.  This analysis proved a major selling point for the drone.  It greatly increased confidence to a potential buyer, knowing that the drone worked effectively, even in rough seas.

 

Focused Engineering

Complete design of the entire drone was a major effort, requiring a large engineering budget.  As a smaller company, our Client didn't have a massive budget.  But they had the skills to design many parts of the vessel themselves.  So DMS focused our efforts.  We restricted engineering to the few specialized areas.  Things like stability, survival, and seakeeping.  These small details really made the difference, adding huge value to the drone.  The Client only paid for engineering in the valuable details.  This flexibility allowed them to achieve much more with a smaller budget.

Related Services

Seakeeping Analysis

Our seakeeping analysis covers everything from a simple motions study . . . up to complex multi-vessel interactions.  We go a step further by providing error analysis on every seakeeping study.  Use the results with confidence, knowing the DMS measured and quantified the quality of your simulations.

Stability Analysis

Ship stability preserves you and protects you against the storm.  When the wind blows and the waves swell . . . the ship holds fast.  That is the strength of stability analysis.

Powering Analysis

Want to travel forever?  Or go so fast that you outrun the waves?  Powering analysis grants that.  At DMS, we can determine the power requirements, size your engine, select a propeller, and more.  DMS focuses on efficient power.  We do more than just throw a big engine at the problem.  We can carefully optimize the vessel to reduce your power requirements.  Go farther, while burning less fuel.

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