Hi, Steve
Thanks for your reply.
Yes, the energy loss is certainly a factor - weight is not as much a
factor, since I have to add 1« ton of ballast anyway(closed up pond).
Cooling... I have access to stainless heat exchangers at a very good price.
As for the electrical drive - I know that it has a lower energy loss, but
the idea of so much stuff that can short out in my engine room is not
appealing until I have mre knowledge of the equipment's degree of
protection.
The hydraulics OTOH can operate if partly submerged - as long as the diesel
can draw breath :-)

So I speculate on - trying to calculate heat loss right now.

I'd rather be sailing....
Ole


Ole,
I have considered this before and rejected it because of excessive
weight, very high cost and very poor efficiency. Consider the size and
weight of the hydraulics rated for 130 HP. Consider the amount of heat
generated in the hydraulic oil in comparison to a conventional gear.
(lost energy) Now, do a cost comparison. I think you will end up
making the same decision. All other concerns like speed and torque are
simply hydraulic configuration issues and are easily resolved.
Now, electric, propulsion. There you have serious possibilities.
Steve

Hydraulic drive not ready for prime time in personal boats... May never
be... Just a function of basic physics, pump a fluid hard enough to do
useful work and you get lots of wasted energy in pumping and heat
losses...

Electric drive not ready for prime time in cruising boats of our
sizes... I spent part of last week on the phone with STI, Siemens, and
a couple others in a desperate search for numbers that would convince
me to put it in my power cat... The numbers just are not there... For
putzing around the harbor in your electric launch it's fine... For
trolling with your bass boat it's fine.. For moving your 1000 foot
cruise liner, it's fine... For a 30-40-50-60 foot boat it's not fine...
As an auxillary for a sail boat, electric may be a workable solution,
but for the sailor who only uses the engine to get in and out of the
harbor or when the wind dies, a conventional inboard or outboard engine
is a better solution... In the years we kept our Pearson sailboat the
most gas I used in a summer was 10 gallons... Not enough to justify a
$30,000 installation...

denny

Your argument is sound, when you consider salt water boats. I am into
building a house boat for inland waterways in Europe, and in this case
electric transmission makes sense, if you can afford a long investment
return time. Part of the energy will come from solar panels, and part
from a generator. The produced energy will be stored in lead-acid
batteries. This makes a complicated machine, yes, but it brings the
ability to save fuel when it becomes very expensive in the next ten
years, and the fun of quiet and smokeless operation most of the time
when on canals. On rivers, the generator is required full time, but this
is only part of the time we ride our boats.

Denny wrote:
Hydraulic drive not ready for prime time in personal boats... May never
be... Just a function of basic physics, pump a fluid hard enough to do
useful work and you get lots of wasted energy in pumping and heat
losses...

Electric drive not ready for prime time in cruising boats of our
sizes... I spent part of last week on the phone with STI, Siemens, and
a couple others in a desperate search for numbers that would convince
me to put it in my power cat... The numbers just are not there... For
putzing around the harbor in your electric launch it's fine... For
trolling with your bass boat it's fine.. For moving your 1000 foot
cruise liner, it's fine... For a 30-40-50-60 foot boat it's not fine...
As an auxillary for a sail boat, electric may be a workable solution,
but for the sailor who only uses the engine to get in and out of the
harbor or when the wind dies, a conventional inboard or outboard engine
is a better solution... In the years we kept our Pearson sailboat the
most gas I used in a summer was 10 gallons... Not enough to justify a
$30,000 installation...

denny