The University of Bath presents

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The University of Bath presents
The Minerva and Seabomb
Presented by will and Tom
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Introduction

• Bath University Racing Submarine Team - BURST
• 2 submarines
• New propeller driven submarine The Minerva
• Modified biomimetic submarine Seabomb.

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The Minerva

• 1 man, propeller driven
• Pilot in prone position, cyclic input, chain
  drive to prop shaft.
• Dive planes, rudder and elevator controlled
  manually via brake cables.
• Uses 3 composites

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Pilot Ergonomics

• Investigation into optimum human input reveals
  the prone cyclic position.
• Shoulder provide reaction to pedalling force
• Increase hull depth compared to previous design
  for race bike crank and pedals

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Design Speed

• Expireometer optimum rpm and exertion duration
• Ergo-meter provided accurate pilot power
  calculations underwater
• Drag testing on full size hull prototype revealed
  drag coefficient.
• Two values provide design speed 6 knots.

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Propeller

• Propeller designed using a software based on
  Lifting Line Theory.
• Inputs to the program
• 6 knot design speed
• Velocity wake profile Testing and CFD
• The propeller has a RP core to match CAD design
• Composite Fiberglass and polyester resin was
  used for strength and waterproof of the propeller

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Hull

• Hull developed from composite investigations
• Conclusion Cork
• 40 stiffer 40 lighter and provides the
  buoyancy
• Environmentally friendly
• - UK aero and marine industry
• - Balsa doesnt form and hardwood
• Doesnt compress under water

Cork
PU Foam
Balsa
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The SeaBomb

• The 2011 SeaBomb is BURSTs platform for
  Innovation.
• Trialing two new innovative systems
• Hydraulic transmission,
• Autopilot system using Multibeam Sonar,
  actuated control surfaces and on board processing

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The SeaBomb

• As a development of the 2007 SeaBomb
• Cyclic input
• Heaving fin propulsion
• As in Minerva a cork sandwich hull.
• Modular transmission

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Heaving Fin

• Optimal fin design found through Scale Modelling
  and Lifting-line software
• Strouhal number (rate of shedding) based on
  tuna fin - Frequency 1-2hz
• Material ABS
• Stiffness of a fish tail
• Durable
• AR is maximized to give optimal efficiency while
  keeping below the diameter of the hull

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Hydraulic Transmission

• Hydraulic transmission used to facilitate rotary
  to linear motion.
• Initial Design Open loop water system.
• Issues Excessive friction and stiction
• Solution Closed loop hydraulic oil system
• Advantages
• Extra lubrication
• High viscosity less leakage

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Sonar Guided Autopilot

• Aim Fully independent control to reduce pilot
  task loading.
• Achieved through

Multibeam Sonar
Actuated fins
P.C. controller
Pressure sensor and Inclonometer
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Fins

• Aim Investigate optimal ARs geometry.
• Result Dolphin Pectoral fin.
• Reduction in induced drag from shedding vortices.

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Safety Buoy

• Flax (linen) and Polylatic acid from corn
  starch
• Completely natural composite using no petro
  chemicals.

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Conclusion

• Have successfully translated the various
  theoretical ideas into tangible designs.
• Minerva is giving us boat to compete
• SeaBomb acts as our step for development.