Tag Archives: CFD

Jet Boats/Ships Don’t Have to be Fuel Hogs

I will present a paper on this subject at
ASNE Day 2015: Engineering America’s Maritime Dominance
March 4-5, 2015 in
Arlington, VA

Military Jet Boats Now Dominant, but Not Sustainable
Valued for their high speed capability and shallow draft, marine jets beat out propellers as the dominant propulsion in commercial and military craft, even though jets consume more fuel at lower speeds. Yet lower speeds are where they spend most of their time.

Water Jet Pump CFD

Office of Naval Research
Water Jet Pump CFD

Automotive and Aircraft Technologies to the Rescue
By incorporating technology from modern aircraft and cars, jet boats can be much more fuel efficient at low and mid-range speeds without sacrificing high-speed capability or the other operational advantages of current technology.

Simulation Saves Time and Money.
My technical paper and presentation also demonstrate the incorporation of variable geometry and electronic controls in computer simulations to test systems and accurately predict performance.  The models developed in this process are directly useful in rapid prototyping.

The graphic above is an example of the development of a marine jet pump using computational fluid dynamics.

My technical paper details computer design and simulation methods, which allow fast, accurate and economical prediction of performance and fuel consumption in any operational profile. The process produces files for use with the latest part prototyping and pilot production methods.


Marine Jet Variable Power Transmission

Never Bet Against a MicroController

Race car with computational fluid dynamicsMarine propulsion has lagged behind other transportation products because it has failed to integrate new technologies to produce innovative benefits in sustainability, safety, reliability, operating costs, manufacturing costs and lifetime ownership costs.

These failures stem from routine reliance on familiar methods of product design, development and manufacturing.  Doing it the same old way is comfortable, but produces too much of the same old results.

Simulation for Performance & Efficiency

Example of computational fluid dynamics image courtesy of Pointwise

Example of computational fluid dynamics (CFD). Image Courtesy of Pointwise. www.pointwise.com

How different would it be if marine propulsion design was not limited by these familiar product design, development, and manufacturing processes?

Let’s say the design process made maximum use of computational methods and simulation to define the mechanical dimensions and requirements of the optimum propulsion system over the expected range of operating speeds and loads.

If motor efficiency, lower emissions, and longer operating life require a variable power transmission as they do in trucks, buses and cars, why not make that part of the design?  

It seems natural that such a system would be best made using design, development and manufacturing methods commonly used for autos, trucks, and large construction equipment.

Fortunately, these methods and services are highly developed, widely available, and ever more economical, which makes this whole approach more practical than traditional methods.

Why Not Boats?

Electronically controlled components, similar to those long found in aircraft, automobiles, and even home appliances, can enhance marine propulsion.

These controls, programming methods, and associated development services are readily available.  This development path is highly automated for very large markets, so is the fastest, most exact, and most economical one available.

The only remaining question is
why has it taken so long for marine propulsion to get here?