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General arrangement and planning
Performance requirements
What are the top speed and cruising speed require-
ments?
The boat/vessel
Define the category of hull type:
• Displacement
• Semi-planning
• Planning
Consider the boat size and estimate weight, LCG
(Longitudinal Centre of Gravity) etc. Drawing informa-
tion (line drawings) is requested, in the best case re-
sistance data from tank tests.
Propulsion system
Search for the most suitable propulsion system and
engine geometry. Think about the characteristics of
different propulsion systems.
Choice of engine
To provide the best performance and characteristics
of an installation it is important to elaborate and iterate
the information shown in the illustration below. Trial
and error is often needed to finally find the essential
set of "performance" requirements the installation
BOAT
VESSEL
REVERSE GEAR
AND PROPELLER
PERFORMANCE
LIMITATIONS
PROPULSION
SYSTEM
POWER
REQUIREMENT
ENGINE
aims to fulfil. Analysis of each contribution may vary
depending on the dominating priorities such as top
speed, economy, safety, etc. Consult Volvo Penta lit-
erature and computer programs or contact the Volvo
Penta organisation for assistance.
Limitations
Consider possible limitations such as engine and pro-
peller dimensions.
Power requirement
Use the data to define the required power. Do not for-
get to consider power losses due to PTOs, climate,
fuel qualities etc.
Engine
Consult Volvo Penta sales literature for the corre-
sponding engine, giving minimum required power at
the correct duty rating. Check the available reverse
gear ratios.
Reverse gear and propeller
Calculate for the optimum gear ratio as well as propel-
ler type and size.
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