ARTICULATION REASONS
Trimmability
The capability to trim up and/or down the drive is
obtained through an hydraulic cylinder called “trim
cylinder”. The ability to trim the Arneson Drives
allows for the propeller submergence to match the engine
horsepower output, thus more power is converted to
producing thrust while the engine is operating closer or
at its rated power curve.
Propeller submergence can be adjusted while underway,
by using a surface piercing propeller in conjunction
with an ASD, allowing selection of the optimum thrust
angle for varying load and sea condition |
Click for sample
(0,9MB)
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Steerability
Steering control and response is maximized when the
propeller function is the essential directional force.
Unlike conventional systems that vector propeller thrust
off an external rudder, the Arneson Surface Drives angle
the propellers in the appropriate direction of motion.
Because the thrust steering the ASD can turn tighter,
with greater control than fixed shaft drives. Tests
shown that positive thrust steering has an effect double
than propeller rudder effect. Maneuverability is
improved at all speed. .Steering is power assisted via
an engine driven pumps located on engines. For safety
reasons a double power steering pump installation is
always suggested. |
Click for sample
1,2MB)
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Reversibility
The Surface Drives have the reputation for poor reversing
characteristics. Unlike Surface fixed shaft system Arneson
Surface Drives can be trimmed down during docking maneuvering
improving a lot reversing.
However, reversing does not only depend by the Surface Drive
System. Historically, Surface Drives equipped vessels have
been high speed vessels (i.e., the original ASD equipped
vessels were all race boats). The propellers designed for this
high speed applications have an extremely inefficient blade
shape for reversing. The leading edge is designed “cleaver
style” on these propellers, very efficient to achieve the
highest top speed but providing poor reverse capability.
New blade designs have been extensively studied by major
propeller manufacturers to match pleasure as well as military
vessel operating requirements.
New blade designs released over the last years have
improved reverse maneuverability in respect to traditional “cleaver”
type design and now harbor performance is very similar to
conventional propeller applications thanks to this development
together with an appropriate hull design and the use of
Arneson articulated Surface Drive system.
The result of such innovative propulsion system can be
summarized as follows:
- 15-30%
speed increase over conventional systems
- 15-30%
increase in fuel efficiency
- Shallow water maneuverability
- Reduced
cavitation
- Larger selection of propellers
- Reduced
underwater appendage drag up to 50%
- Positive
thrust steering- superior maneuverability
- Maintenance
simplicity- less than 20 moving parts
- Low maintenance requirements
- Greater flexibility of engine placement
- Less vibration- smoother running condition
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