BOOT ’09 aftermath

  Hurricane Hot Chocolate blew through the Feller Yachting prototyping workshop and left a debris field that we’ve only just managed to clear.  Our Appearance at the Boot exhibition in Düsseldorf was a wonderful experience and a terrific success.  Almost eight kilograms of espresso-roast beans were consumed by the admiring crowds and  a dozen bottles of rum made hot chocolate extra special for our afternoon visitors and neighbors.  We miss you already.

  To everyone who stopped and smiled, 

  Thank You.

  From your friends at Feller Yachting.

Hot Chocolate 540

Defining the Dynamic Maximum

  A ride over rough water in a fast motorboat can be an unpleasant event.  The violent motion of a planing hull crashing over waves is likely more rough than any other mode of transportation a person will experience.  Often speed must be reduced to prevent slamming, prolonging the uncomfortable journey and consuming extra fuel, as planing hulls are less efficient at speeds below planing.  

   To address this problem, a vessel must be seaworthy and capable of high speed, be efficient at all speeds and must prosess a more comfortable motion in rough water.

In designing a vessel that satisfies these requirements, our approach has been to define what we call “the dynamic maximum”.  The dynamic maximum is a theoretical point of optimum balance of design criteria, where combined performance in all aspects is greatest.  It can only be arrived at through experimentation, in our case with models in a tank testing scenario.  The equilibrium is reached when a planing hull has a minimum of wetted surface area and wind resistance yet sufficient planing properties to exceed hull speed.

  Our “Dymax” hull represents a major innovation in pleasure craft.  It’s unique design gives it  extraordinary hydrodynamic properties.  The narrow entry parts the water with minimum resistance and the rounded midship sections displace smoothly and evenly. 

A pronounced step draws air under the clean aft sections, further reducing drag.  The result is an extremely smooth ride at all speeds.  Acceleration from displacement to planing mode is quick with none of the bow-high pitch experienced in ordinary planing hulls.  The boats cruise comfortably and efficiently at high speed with no tendancy to porpoise or oscillate. 

The easy, rounded sections act as shock absorbers, eliminating pounding.  At rest, the narrow hull is stabilized like a trimaran by the inflated tubes aft.

  The ride of a dymax hull is the dynamic maximum of comfortable performance, an elegant expression of the craft of yachting.

DYMAX SLENDERPLANE

DOING MORE WITH LESS

Drawing on pioneering work in the field of high speed hull form development carried out in the early part of the last century and combined with the advantages of modern construction materials and lightweight engines, designer Uwe Feller has developed an extraordinarily efficient vessel.  Refined with test-tank modeling and computer aided design, the hull has been prototyped in Germany.  Preliminary sea trials have shown exceptional efficiency and unequaled ride comfort.

Dubbed “Dymax”, the hull design is a slender, stepped planing hull with deep rounded sections.  The fine entry parts water effortlessly and provides little bouyancy forward, minimizing the pitching effect of waves.  The easy, rounded sections smoothly accelerate water off the chines and ventilated step.  Air drawn under the boat by the step reduces the wetted surface and thus the resistance of the hull.  The narrow waterline of the hull is stabilized at rest by inflated tubes, which offer good protection alongside as well.

With just 33 kilowatts, the 5.3 meter prototype exceeded 60 kilometers per hour with two passengers.  Acceleration is steady with little ‘hump’ resistance and no ‘bow-high pitch before planing.  The careful placement of the step ensures the ride is level and smooth.  Cornering is tight and precise, it’s a thrilling boat to drive.

Testing continues with more engine configurations while production designs are being finalized.  An appearance at Boot in Dusseldorf is planned.  For more information, visit felleryachting.de

Marine Catalytic Converters

The challenge of emission reduction in marine propulsion systems has in some cases been addressed in a manner of reluctant adherence to imposed government and trade standards.  To curb nitrous oxide, carbon monoxide and particulate emissions, recreational boat manufacturers are applying readily available automotive catalytic converters.  These systems are highly effective in controlled emission tests, a testament to the well-established catalyst compound applied to the substrate surface.  The most common substrate in automotive catalytic converters is a ceramic comb.  These ceramic catalyst blocks can become fragile and their lifespan in marine applications has proven short.  Faced with the high cost of replacing a failed catalytic converter, operators of recreation boats equipped with poorly designed emission reduction systems may choose to remove them altogether for a cheaper repair bill and an possible increase in performance.

If a manufacturer of recreational boats claims a reduction of harmful emissions from their products, it must be acheived in a manner that will be effective over the entire products lifespan.  If a catalytic converter is employed, it must be robust to withstand the shocks sustained in a high-speed boat.

Feller engineering has produced a patented all-metal catalytic converter for the recreational marine propulsion industry.  The catalyst substrate withstands extreme temperature and water immersion with excellent flow characteristics and even heat distribution.  Destruction testing proved impossible, with the catalyst substrate outlasting the engine in each test.  High reductions in emissions have been recorded with negligible loss of performance.