On Sat, 15 Dec 2007 09:50:00 +0100, Heikki wrote:

John C. wrote:

Run it as a generator and use it to charge an oversized bank of batteries.
With an electric motor you will gain variable speed and direction without
have an engineering nightmare.

I have been speculating about a diesel-electric propulsion for a smallish
sailboat. Does anyone have links to, or experience with, small electric
motors that are suitable for continuous use - most of my googling finds bow
thrusters and other extra machinery.

I am thinking of a fairly small engine, say 5-10 Hp, to be used mostly in
manouvering in and out of marinas, and occasionally coming home from a calm
sea. Would it make sense to mount the whole engine on the transom-hung
rudder? That way it could turn with the rudder, and give good steering in
both directions. When not in use, it could be lifted out of the water, so I
could use a decent size of propeller for it.

Would anyone care to shoot the idea down before I get too attached to it.
The whole project is on a dreaming level, I won't be building anything for
the next many years. But I still want to design it as if I was going to
build it some day soon...

Regards

Heikki
(Copenhagen, Denmark)


I don't have the answer to your question, but I wanted to tell you that I
fell in love with Copenhagen a few years back when visiting your country.
We stayed in a campground at the edge of the city and took the train in
each day. What a beautiful city and port.

I've never had a more enjoyable time than taking a harbor/city cruise
through Copenhagen. We stopped for lunch here, of course!

http://tinyurl.com/yu575t

Sorry for the interruption. There are a lot of very smart folks here who
should be able to help with your question.
--
John H

On Sat, 15 Dec 2007 09:50:00 +0100, Heikki wrote:

John C. wrote:

Run it as a generator and use it to charge an oversized bank of batteries.
With an electric motor you will gain variable speed and direction without
have an engineering nightmare.

I have been speculating about a diesel-electric propulsion for a smallish
sailboat. Does anyone have links to, or experience with, small electric
motors that are suitable for continuous use - most of my googling finds bow
thrusters and other extra machinery.

I am thinking of a fairly small engine, say 5-10 Hp, to be used mostly in
manouvering in and out of marinas, and occasionally coming home from a calm
sea. Would it make sense to mount the whole engine on the transom-hung
rudder? That way it could turn with the rudder, and give good steering in
both directions. When not in use, it could be lifted out of the water, so I
could use a decent size of propeller for it.

Would anyone care to shoot the idea down before I get too attached to it.
The whole project is on a dreaming level, I won't be building anything for
the next many years. But I still want to design it as if I was going to
build it some day soon...

Regards

Heikki
(Copenhagen, Denmark)

Yes, I guess I'd have to say "why"? With a small diesel engine you
would have a variable thrust device without the added complexity of
the electrical motor, controller, etc., not to mention the "over sized
bank of batteries".

Bruce-in-Bangkok
(Note:remove underscores
from address for reply)

On Sat, 15 Dec 2007 09:50:00 +0100, Heikki wrote:

John C. wrote:

Run it as a generator and use it to charge an oversized bank of batteries.
With an electric motor you will gain variable speed and direction without
have an engineering nightmare.

I have been speculating about a diesel-electric propulsion for a smallish
sailboat. Does anyone have links to, or experience with, small electric
motors that are suitable for continuous use - most of my googling finds bow
thrusters and other extra machinery.

There are electric fishing motors, in the one horsepower or less
class. Maybe enough power for an under twenty foot boat. Not good on a
windy day.

I am thinking of a fairly small engine, say 5-10 Hp, to be used mostly in
manouvering in and out of marinas, and occasionally coming home from a calm
sea. Would it make sense to mount the whole engine on the transom-hung
rudder? That way it could turn with the rudder, and give good steering in
both directions. When not in use, it could be lifted out of the water, so I
could use a decent size of propeller for it.

There is the tried and true outboard motor. Hanging stuff on the
rudder sounds like a poor approach to me. Not to mention ugly.

Would anyone care to shoot the idea down before I get too attached to it.

Shouldn't be too hard.

Casady

Hi John,
Ive been thinking much along the same lines for my some-day dream boat
(60+foot sailing cat). I'd ultimately like to have redundancy in all
systems with maybe 4 props; one in each hull and twin drop down props in the
deck. While it initally may sound stupid, I'd envisaged having many systems
tied together. I was thinking hi speed hydraulics for reliability, with
many tie-ins. here would be diesel generators (x1 or x2) with battery
banks, and an option to either have the diesels direct drive the hydraulics
or charge batteries, or both. There would then be electric motors to drive
hydraulics on demand also. The two props in the hulls would be hydraulic
drive, while the two in the deck would probably just be some form of
standalone outboard (also diesel).

Further to all this, many other items on the boat would also be hydraulic
driven; compressor for refrigeration, whinches, anchor whicn etc and could
all be driven by either the diesel motor running the hydraulic pumps, or the
electric motors running the same pumps. The props in the water would also
be able to function as generators, and there would be other options for
generating electricity (wind generators, solar etc). this would give
numerous options for drive, and with 2 of everything you would have plenty
of redundancy. The beauty of electric drive is power on demand; no need to
start motors, stalling etc... the power is there straight away. This is a
huge plus in emergency situations, and is just nice in having silent drive
for day sailing.

The downside to all this is efficiency. By running multiple systems like
this your efficiency gets down pretty low. From my point of view though, I
am hoping to run a pretty minimalist scheme of things electrically; no tv,
dvd, minimal refrigeration, minimal nav, LED nav lights, no microwave etc
etc, so the electric is mainly for propulsion. With a boat used mainly as a
sailing boat, I would hope that I can keep propulsion usage low enough that
it could be recovered by means of solar and wind generation meaning that
diesel was only there as a backup. In a cruising mentality, you may be
happy to wait another week rather than burn some diesel. I'm trying to see
the longer view here, but may be completely wrong. While some very large
capacity ships have gone to diesel over electric, most of the stuff
available is still diesel direct drive. For the most part the diesel over
electric stuff is running exotic propulsion systems anyway (not normal
props)

There are some inboard style electric motors available on ebay in australia
in the last year, i think the name is thiele? they advertise up to 44hp,
and sell controllers etc to suit. they have the necessary components to use
the prop to drive the motor as a generator also. a bit of hunting around
should get some useful information. Im far from the buying stage myself,
maybe in 10 years or so

Shaun


"Heikki" wrote in message
...
John C. wrote:

Run it as a generator and use it to charge an oversized bank of
batteries.
With an electric motor you will gain variable speed and direction without
have an engineering nightmare.

I have been speculating about a diesel-electric propulsion for a smallish
sailboat. Does anyone have links to, or experience with, small electric
motors that are suitable for continuous use - most of my googling finds
bow
thrusters and other extra machinery.

I am thinking of a fairly small engine, say 5-10 Hp, to be used mostly in
manouvering in and out of marinas, and occasionally coming home from a
calm
sea. Would it make sense to mount the whole engine on the transom-hung
rudder? That way it could turn with the rudder, and give good steering in
both directions. When not in use, it could be lifted out of the water, so
I
could use a decent size of propeller for it.

Would anyone care to shoot the idea down before I get too attached to it.
The whole project is on a dreaming level, I won't be building anything for
the next many years. But I still want to design it as if I was going to
build it some day soon...

Regards

Heikki
(Copenhagen, Denmark)

On Dec 15, 2:50 am, Heikki wrote:
John C. wrote:
Run it as a generator and use it to charge an oversized bank of batteries.
With an electric motor you will gain variable speed and direction without
have an engineering nightmare.

I have been speculating about a diesel-electric propulsion for a smallish
sailboat. Does anyone have links to, or experience with, small electric
motors that are suitable for continuous use - most of my googling finds bow
thrusters and other extra machinery.

I am thinking of a fairly small engine, say 5-10 Hp, to be used mostly in
manouvering in and out of marinas, and occasionally coming home from a calm
sea. Would it make sense to mount the whole engine on the transom-hung
rudder? That way it could turn with the rudder, and give good steering in
both directions. When not in use, it could be lifted out of the water, so I
could use a decent size of propeller for it.

Would anyone care to shoot the idea down before I get too attached to it.
The whole project is on a dreaming level, I won't be building anything for
the next many years. But I still want to design it as if I was going to
build it some day soon...

Regards

Heikki
(Copenhagen, Denmark)

I would get a lower unit from an outboard and mount it permanently on
the bottom of the hull and then mount a 32V military surplus motor on
the inside and use the rudder for steering. Use three 12V batteries
in series for 36V which will drop to about 32V when under load. The
US Military made several large 32V motors that were used for fuel pump
in Jets and for power generation in the old prop planes. I have a 15
HP (Jet fuel pump) and a 25 HP (I think this came out of a B-25) that
I picked up at surplus prices a few years ago to make an electric car
which I later disassembled (yes it was successful). Am now thinking
about the 25HP for a small single seat hydroplane for short but fast
runs.

Heikki wrote:
John C. wrote:

Run it as a generator and use it to charge an oversized bank of batteries.
With an electric motor you will gain variable speed and direction without
have an engineering nightmare.

I have been speculating about a diesel-electric propulsion for a smallish
sailboat. Does anyone have links to, or experience with, small electric
motors that are suitable for continuous use - most of my googling finds bow
thrusters and other extra machinery.

I am thinking of a fairly small engine, say 5-10 Hp, to be used mostly in
manouvering in and out of marinas, and occasionally coming home from a calm
sea. Would it make sense to mount the whole engine on the transom-hung
rudder? That way it could turn with the rudder, and give good steering in
both directions. When not in use, it could be lifted out of the water, so I
could use a decent size of propeller for it.

Would anyone care to shoot the idea down before I get too attached to it.
The whole project is on a dreaming level, I won't be building anything for
the next many years. But I still want to design it as if I was going to
build it some day soon...

Regards

Heikki
(Copenhagen, Denmark)



Bow thruster type motor or electric trolling motor

Heikki wrote:
John C. wrote:

Run it as a generator and use it to charge an oversized bank of batteries.
With an electric motor you will gain variable speed and direction without
have an engineering nightmare.

I have been speculating about a diesel-electric propulsion for a smallish
sailboat. Does anyone have links to, or experience with, small electric
motors that are suitable for continuous use - most of my googling finds bow
thrusters and other extra machinery.

I am thinking of a fairly small engine, say 5-10 Hp, to be used mostly in
manouvering in and out of marinas, and occasionally coming home from a calm
sea. Would it make sense to mount the whole engine on the transom-hung
rudder? That way it could turn with the rudder, and give good steering in
both directions. When not in use, it could be lifted out of the water, so I
could use a decent size of propeller for it.

Would anyone care to shoot the idea down before I get too attached to it.
The whole project is on a dreaming level, I won't be building anything for
the next many years. But I still want to design it as if I was going to
build it some day soon...

BANG! (whistling sound as the idea spirals down in flames :-)

Seriously, if you just want to get in and out of the marina, look for
off-the-shelf electric outboards. But 5-10 hp is probably going to be
hard to find. Check out the following link for more info on electric
boats and gas/diesel electric conversions. Good luck!

http://www.econogics.com/ev/evboats.htm

Keith Hughes

PS. Just for clarity of terminology on the US side of the pond, Electric
= Motor, Gasoline/Diesel/Fuel = Engine.

On Sat, 15 Dec 2007 09:50:00 +0100 Heikki
) wrote:
John C. wrote:

Run it as a generator and use it to charge an oversized bank of batteries.
With an electric motor you will gain variable speed and direction without
have an engineering nightmare.

I have been speculating about a diesel-electric propulsion for a smallish
sailboat. Does anyone have links to, or experience with, small electric
motors that are suitable for continuous use - most of my googling finds bow
thrusters and other extra machinery.

I am thinking of a fairly small engine, say 5-10 Hp, to be used mostly in
manouvering in and out of marinas, and occasionally coming home from a calm
sea. Would it make sense to mount the whole engine on the transom-hung
rudder? That way it could turn with the rudder, and give good steering in
both directions. When not in use, it could be lifted out of the water, so I
could use a decent size of propeller for it.

Would anyone care to shoot the idea down before I get too attached to it.
The whole project is on a dreaming level, I won't be building anything for
the next many years. But I still want to design it as if I was going to
build it some day soon...

Regular outboards do have a fair weight/hp compared to e-motor and
batteries. The only thin you have to worry about is fuel. Or how did you
plan to fill your batteries?

--
Richard
e-mail: vervang/replace invalid door/with NL.net

Look into golf cart motors. Consider duty cycle and run times with respect
to motor choice and battery bank size. Larger engines can be found in the
fork truck industry. Both the golf cart and fork truck would provide speed
and direction controls as well as basic mounting design. Your small diesel
generator may need to run much longer than your motor and or you will
require dockside recharging and use the diesel as back and top-off while at
sea. Keeping the generator output close to the energy needs of the motor
will increase the overall efficiency of the system. It would be useless to
require 4 hours of charging to produce the energy needed for 15 minutes of
motoring unless the battery bank was large enough to carry reserve energy in
far excess of your typical needs. The primary charge would then come from
dockside sources and your generator would be always on stand by.

There is a lot of info on the net about hybrid electric craft. You just need
to apply the information to your specific application.



"Heikki" wrote in message
...
John C. wrote:

Run it as a generator and use it to charge an oversized bank of
batteries.
With an electric motor you will gain variable speed and direction without
have an engineering nightmare.

I have been speculating about a diesel-electric propulsion for a smallish
sailboat. Does anyone have links to, or experience with, small electric
motors that are suitable for continuous use - most of my googling finds
bow
thrusters and other extra machinery.

I am thinking of a fairly small engine, say 5-10 Hp, to be used mostly in
manouvering in and out of marinas, and occasionally coming home from a
calm
sea. Would it make sense to mount the whole engine on the transom-hung
rudder? That way it could turn with the rudder, and give good steering in
both directions. When not in use, it could be lifted out of the water, so
I
could use a decent size of propeller for it.

Would anyone care to shoot the idea down before I get too attached to it.
The whole project is on a dreaming level, I won't be building anything for
the next many years. But I still want to design it as if I was going to
build it some day soon...

Regards

Heikki
(Copenhagen, Denmark)

Richard van den Berg wrote:

Regular outboards do have a fair weight/hp compared to e-motor and
batteries. The only thin you have to worry about is fuel. Or how did you
plan to fill your batteries?

Oh, I was planning to have a diesel engine (and a generator) running most of
the time to provide the electricity. The idea was to be able to place the
generator engine where I wanted it, and the propelller(s) and the driving
engine where they would be most useful. Instead of a solid shaft, I would
have flexible cables in between. I could run it on the batteries for a
minutes, if I needed extra manouvering, but in most cases, the power would
come from the generator. Also, I was hoping that the electric propulsion
would be smaller and lighter, so it would be easier to lift out of the
water when going by sail...

- Heikki