I disagree with your thoughts that electric motor
drive system are more "expensive than deisel because
they are designed to last longer". I have been
involved in the sales and applications DC and AC motors
and controlers for variable speed systems in
industrial systems for 30 years. The quality has incresed
and the prices have decreased. The problem with
marine use is that there is a lack of competition and/
or a lack crossover from the industrial world to the
marine world. A DC Motor has brushes. Todays motors have
brushes which are desigend to run for 10000 hours when
properly applied. Both AC and DC Motors have bearing they
have a MTBF (mean time between failure)equal to or
beter than the brushes in DC Motors. The cost of
controls (amplifiers) in the industrial application has
gone down 10 fold in the last 20 years but these
controls have not been applied to marine applications for
whatever reason. The only other item in the system is
batteries and due to the push for electric cars there is a
lot of work being done to make them have better
capacity and lower the cost and weight at the same time. I
feel that it is feasable to put together an effecient
cost effective electric marine propulsion system with
todays componets that will be be every bit as good if
not better then the fossil fuel drive system that are
being used today at a price that is competive to fossil
fuel propulsion systems.
