I am building a 60 foot aluminum sailyacht and considering using diesel
electric propulsion with 2 identical diesel enigins of 70 - 100 hp. The
builder is not very experienced in ths field so I am doing some fieldwork
myself .

Anyone with experience in diesel eletric solutions in this size for sailing
yachts?

Cheers.

Marc

I've gone around the diesel electric question on a few research vessels
where it is a good solution.

It is going to be quite expensive.

It makes most sense when the loads while the boat is not moving are a
significant percentage of propulsion loads. This doesn't fit the ususal
cruiser profile (except maybe for Skip and Lydia

You had better have a builder who really understands it. There are going to
be some complex boxes and equipment in between the generators and the props.
Keeping them cool and dry will be a challange. The wiring will be unlike
anything most builders have seen.

It's going to take up a lot more space than a conventional propulsion plant.
There will be some effeciency losses so you will need to carry more fuel on
a boat that already is devoting extra space and weight to this enthusiasm.

When you have problems with it and pull into Pango Nowhere, it's going to
be amusing watching the locals trying to figure out how to fix it.

I love diesel electric but it would not have crossed my mind to try it in a
60 foot sailboat. If having a DE sailboat is a goal in itself because you
like to tinker and want to be a pioneer, cool. If you just want to sail and
cruise, I would forget it. You can use that space, weight, money, and
research effort much more usefully.

--
Roger Long

On Wed, 1 Aug 2007 08:36:11 -0400, "Roger Long"
wrote:

I've gone around the diesel electric question on a few research vessels
where it is a good solution.

It is going to be quite expensive.

It makes most sense when the loads while the boat is not moving are a
significant percentage of propulsion loads. This doesn't fit the ususal
cruiser profile (except maybe for Skip and Lydia

You had better have a builder who really understands it. There are going to
be some complex boxes and equipment in between the generators and the props.
Keeping them cool and dry will be a challange. The wiring will be unlike
anything most builders have seen.

It's going to take up a lot more space than a conventional propulsion plant.
There will be some effeciency losses so you will need to carry more fuel on
a boat that already is devoting extra space and weight to this enthusiasm.

When you have problems with it and pull into Pango Nowhere, it's going to
be amusing watching the locals trying to figure out how to fix it.

I love diesel electric but it would not have crossed my mind to try it in a
60 foot sailboat. If having a DE sailboat is a goal in itself because you
like to tinker and want to be a pioneer, cool. If you just want to sail and
cruise, I would forget it. You can use that space, weight, money, and
research effort much more usefully.


There was an article in "PassageMaker" a while back about the
conversion of a trawler yacht from diesel to diesel-electric. It,
frankly, looked like a corporate promotion article -- perfectly
lighted photos and from the prospectives , obviously professional
camera equipment, but anyway.

The crux of the article was that the owner removed two main engines
and replaced them with a single, larger prime mover driving either an
alternator or generator (I don't remember which way he got his
electricity). Each of the original propellers/shafts, etc, were
replaced by DC motors directly coupled to the shafts. The whole
caboodle was SCR controlled and the genrator/alternator and both DC
drive motors were water cooled. The electric controls looked similar
to the SCR controls in an off shore drilling rig.

From looking at the pictures there appeared to be little of the
installation that was "off the shelf" and my guess was that the whole
installation must have been far in excess of what the original twin
engine installation was.






Bruce in Bangkok
(brucepaigeATgmailDOTcom)

Roger & Bruce; thanks for your reaction. Pioneering is nice.. but not at any
price ;-) Not my main reason for looking into this...

My main objectives are :
- having a backup engine with which she should at least run 4 kn without
having the need for double propellors (too much drag it's a fast sailing
yacht nog an moto sailor ;-)
- not needing a seperate generator by using one of the main engines as a
generator
- less noise / vibration?

Hope to get in contact with someone who has a 60 or 70 foot sailing yacht
running with diesel eletric propulsion. If there is any :-)

Grtz Marc
sy Beluga
wrote in message
...
On Wed, 1 Aug 2007 08:36:11 -0400, "Roger Long"
wrote:

I've gone around the diesel electric question on a few research vessels
where it is a good solution.

It is going to be quite expensive.

It makes most sense when the loads while the boat is not moving are a
significant percentage of propulsion loads. This doesn't fit the ususal
cruiser profile (except maybe for Skip and Lydia

You had better have a builder who really understands it. There are going
to
be some complex boxes and equipment in between the generators and the
props.
Keeping them cool and dry will be a challange. The wiring will be unlike
anything most builders have seen.

It's going to take up a lot more space than a conventional propulsion
plant.
There will be some effeciency losses so you will need to carry more fuel
on
a boat that already is devoting extra space and weight to this enthusiasm.

When you have problems with it and pull into Pango Nowhere, it's going to
be amusing watching the locals trying to figure out how to fix it.

I love diesel electric but it would not have crossed my mind to try it in
a
60 foot sailboat. If having a DE sailboat is a goal in itself because you
like to tinker and want to be a pioneer, cool. If you just want to sail
and
cruise, I would forget it. You can use that space, weight, money, and
research effort much more usefully.


There was an article in "PassageMaker" a while back about the
conversion of a trawler yacht from diesel to diesel-electric. It,
frankly, looked like a corporate promotion article -- perfectly
lighted photos and from the prospectives , obviously professional
camera equipment, but anyway.

The crux of the article was that the owner removed two main engines
and replaced them with a single, larger prime mover driving either an
alternator or generator (I don't remember which way he got his
electricity). Each of the original propellers/shafts, etc, were
replaced by DC motors directly coupled to the shafts. The whole
caboodle was SCR controlled and the genrator/alternator and both DC
drive motors were water cooled. The electric controls looked similar
to the SCR controls in an off shore drilling rig.

From looking at the pictures there appeared to be little of the
installation that was "off the shelf" and my guess was that the whole
installation must have been far in excess of what the original twin
engine installation was.






Bruce in Bangkok
(brucepaigeATgmailDOTcom)

"Marc" wrote


My main objectives are :
- having a backup engine with which she should at least run 4 kn without
having the need for double propellors (too much drag it's a fast sailing
yacht nog an moto sailor ;-)

You already have the back up. They are called sails. If a diesel used in
auxilliar sailboat service doesn't run, it is as apt to be a fuel problem as
anything else. Your second engine will then be down as well.

- not needing a seperate generator by using one of the main engines as a
generator
- less noise / vibration?

A big generator is going to be noiser than a small one. One large enough to
drive the boat is going to be big. Air supply and exhaust are major and
hard to control noise sources. Bigger generators just make it even more
difficult.
Generator's are not happy running at light loads. Unless your hotel load
approaches 50% of your propulsion load running just the one generator for
ship's service will probably result in it's running too lightly. If you do
put in enough hotel load, AC, Jacuzzi, etc., to load up the generator, where
are you going to carry all the fuel?


Hope to get in contact with someone who has a 60 or 70 foot sailing yacht
running with diesel eletric propulsion. If there is any :-)

I'll be amazed if you find one for the above reasons. If you do, please let
us know.

Grtz Marc
sy Beluga
wrote in message
...
On Wed, 1 Aug 2007 08:36:11 -0400, "Roger Long"
wrote:

I've gone around the diesel electric question on a few research vessels
where it is a good solution.

It is going to be quite expensive.

It makes most sense when the loads while the boat is not moving are a
significant percentage of propulsion loads. This doesn't fit the ususal
cruiser profile (except maybe for Skip and Lydia

You had better have a builder who really understands it. There are going
to
be some complex boxes and equipment in between the generators and the
props.
Keeping them cool and dry will be a challange. The wiring will be unlike
anything most builders have seen.

It's going to take up a lot more space than a conventional propulsion
plant.
There will be some effeciency losses so you will need to carry more fuel
on
a boat that already is devoting extra space and weight to this
enthusiasm.

When you have problems with it and pull into Pango Nowhere, it's going
to
be amusing watching the locals trying to figure out how to fix it.

I love diesel electric but it would not have crossed my mind to try it in
a
60 foot sailboat. If having a DE sailboat is a goal in itself because you
like to tinker and want to be a pioneer, cool. If you just want to sail
and
cruise, I would forget it. You can use that space, weight, money, and
research effort much more usefully.


There was an article in "PassageMaker" a while back about the
conversion of a trawler yacht from diesel to diesel-electric. It,
frankly, looked like a corporate promotion article -- perfectly
lighted photos and from the prospectives , obviously professional
camera equipment, but anyway.

The crux of the article was that the owner removed two main engines
and replaced them with a single, larger prime mover driving either an
alternator or generator (I don't remember which way he got his
electricity). Each of the original propellers/shafts, etc, were
replaced by DC motors directly coupled to the shafts. The whole
caboodle was SCR controlled and the genrator/alternator and both DC
drive motors were water cooled. The electric controls looked similar
to the SCR controls in an off shore drilling rig.

From looking at the pictures there appeared to be little of the
installation that was "off the shelf" and my guess was that the whole
installation must have been far in excess of what the original twin
engine installation was.






Bruce in Bangkok
(brucepaigeATgmailDOTcom)

So... you might be right. No reason for me to look into this option any
further. Spend my money on a good main engine and a nice small generator and
saving a lot for extended cruising time ;-)

"Roger Long" wrote in message
...

"Marc" wrote


My main objectives are :
- having a backup engine with which she should at least run 4 kn without
having the need for double propellors (too much drag it's a fast
sailing yacht nog an moto sailor ;-)

You already have the back up. They are called sails. If a diesel used in
auxilliar sailboat service doesn't run, it is as apt to be a fuel problem
as anything else. Your second engine will then be down as well.

- not needing a seperate generator by using one of the main engines as a
generator
- less noise / vibration?

A big generator is going to be noiser than a small one. One large enough
to drive the boat is going to be big. Air supply and exhaust are major
and hard to control noise sources. Bigger generators just make it even
more difficult.
Generator's are not happy running at light loads. Unless your hotel load
approaches 50% of your propulsion load running just the one generator for
ship's service will probably result in it's running too lightly. If you
do put in enough hotel load, AC, Jacuzzi, etc., to load up the generator,
where are you going to carry all the fuel?


Hope to get in contact with someone who has a 60 or 70 foot sailing yacht
running with diesel eletric propulsion. If there is any :-)

I'll be amazed if you find one for the above reasons. If you do, please
let us know.

Grtz Marc
sy Beluga
wrote in message
...
On Wed, 1 Aug 2007 08:36:11 -0400, "Roger Long"
wrote:

I've gone around the diesel electric question on a few research vessels
where it is a good solution.

It is going to be quite expensive.

It makes most sense when the loads while the boat is not moving are a
significant percentage of propulsion loads. This doesn't fit the ususal
cruiser profile (except maybe for Skip and Lydia

You had better have a builder who really understands it. There are
going to
be some complex boxes and equipment in between the generators and the
props.
Keeping them cool and dry will be a challange. The wiring will be
unlike
anything most builders have seen.

It's going to take up a lot more space than a conventional propulsion
plant.
There will be some effeciency losses so you will need to carry more fuel
on
a boat that already is devoting extra space and weight to this
enthusiasm.

When you have problems with it and pull into Pango Nowhere, it's going
to
be amusing watching the locals trying to figure out how to fix it.

I love diesel electric but it would not have crossed my mind to try it
in a
60 foot sailboat. If having a DE sailboat is a goal in itself because
you
like to tinker and want to be a pioneer, cool. If you just want to sail
and
cruise, I would forget it. You can use that space, weight, money, and
research effort much more usefully.


There was an article in "PassageMaker" a while back about the
conversion of a trawler yacht from diesel to diesel-electric. It,
frankly, looked like a corporate promotion article -- perfectly
lighted photos and from the prospectives , obviously professional
camera equipment, but anyway.

The crux of the article was that the owner removed two main engines
and replaced them with a single, larger prime mover driving either an
alternator or generator (I don't remember which way he got his
electricity). Each of the original propellers/shafts, etc, were
replaced by DC motors directly coupled to the shafts. The whole
caboodle was SCR controlled and the genrator/alternator and both DC
drive motors were water cooled. The electric controls looked similar
to the SCR controls in an off shore drilling rig.

From looking at the pictures there appeared to be little of the
installation that was "off the shelf" and my guess was that the whole
installation must have been far in excess of what the original twin
engine installation was.






Bruce in Bangkok
(brucepaigeATgmailDOTcom)

On Wed, 1 Aug 2007 16:44:41 +0200, "Marc" wrote:

Roger & Bruce; thanks for your reaction. Pioneering is nice.. but not at any
price ;-) Not my main reason for looking into this...

My main objectives are :
- having a backup engine with which she should at least run 4 kn without
having the need for double propellors (too much drag it's a fast sailing
yacht nog an moto sailor ;-)
- not needing a seperate generator by using one of the main engines as a
generator
- less noise / vibration?

Consider putting a folding or feathering prop on the "wing" engine to
minimize drag. Mount two large alternators on each engine (200+amps),
and use them to drive a large battery bank and redundant inverters.
That will be much cheaper to build and service than a diesel electric
system, and will give you full backup for everything. Many long range
cruising trawlers are being built that way.

On Wed, 01 Aug 2007 21:00:52 -0400, Wayne.B
wrote:

On Wed, 1 Aug 2007 16:44:41 +0200, "Marc" wrote:

Roger & Bruce; thanks for your reaction. Pioneering is nice.. but not at any
price ;-) Not my main reason for looking into this...

My main objectives are :
- having a backup engine with which she should at least run 4 kn without
having the need for double propellors (too much drag it's a fast sailing
yacht nog an moto sailor ;-)
- not needing a seperate generator by using one of the main engines as a
generator
- less noise / vibration?

Consider putting a folding or feathering prop on the "wing" engine to
minimize drag. Mount two large alternators on each engine (200+amps),
and use them to drive a large battery bank and redundant inverters.
That will be much cheaper to build and service than a diesel electric
system, and will give you full backup for everything. Many long range
cruising trawlers are being built that way.

You are talking about a 60 ft. sail boat. right?

Generally sail boats have auxiliary engines for those times that the
wind doesn't blow. There are also motor-sailers with somewhat bigger
engines but they really don;t go much faster.

I'm assuming that you will have a modern fin keel, broad beam, shallow
hull depth, type of boat with minimum skin friction. I did a really
quick calculation, assuming 20,000 lbs. displacement and came up with
45 shaft H.P., Shaft RPM of 1100 and a speed of about hull speed.

Now, that is probably a bit underpowered as you will be going "up
hill" sometimes but say you add another 25 - 30% and you still aren't
talking about a very big engine.

You've already decided on a sail boat so you have one source of power
and a secondary, the auxiliary diesel. Now do a little research. Go
down to the commercial docks and see how many commercial boats, guys
that spend their whole lives on the water, have more then one source
of moving the boat. The world's fishing fleet is probably 99% single
diesel engine powered and if you've ever been on the Grand Banks in
the winter time that alone should convince you that a second engine is
not really vital to life and happiness.

Lastly, if you are like most owners of 60 ft. bespoken yachts you are
not in the first blush of youthfulness so either you have a crew or a
really strong wife or you are going to need powered winches. So you
have to figure on a gen-set that runs much of the time, if only to
operate the autopilot.

So there you go. A sixty ft. mast and enough dacron to build a circus
tent, a 75-100 H.P. auxiliary engine and a generator set.

And round the world you go =:-)


Bruce in Bangkok
(brucepaigeATgmailDOTcom)

On Aug 1, 4:44 am, "Marc" wrote:
....
My main objectives are :
- having a backup engine with which she should at least run 4 kn without
having the need for double propellors (too much drag it's a fast sailing
yacht nog an moto sailor ;-)
....

Well, I don't want to get into the my boat is faster than... ALL
sailboats are slow. Still, I do have a cruising boat with top speeds
right around twenty knots under sail and it has two engines and two
props. It also has two rudders, two dagger boards and two hulls...
An interesting side effect of having two propulsion engines is that
the props are sized to WOT with both engines running and are thus
"over propped" when only one motor is running. I think this is good
since it means that I can run one engine slowly and still have it
loaded up when motoring through a calm. I don't have a pyrometer on
the engines and they are too small for commercially available flow
meters so I can't really claim to know if the theory really works, but
I run on the assumption that it does... Anyway, it might be fun to
explore the differences in installed cost of twins vs a single and bow
thruster. I think it would be easier to get home on one twin than on
one bow thruster . Another possibility would be to put in a
continuous duty drop down style bow thruster on an "Z" drive. Your
genset could then run that as a "get me into the dock now that I've
sailed home" engine.

-- Tom.

wrote in news:ar41b3tsf5888c1jdihvpusao9orv4vp8d@
4ax.com:

both DC
drive motors were water cooled.

That right there speaks volumes for how efficient it is.



Larry
--
While in Mexico, I didn't have to press 1 for Spanish.
While in Iran, I didn't have to press 1 for Farsi, either.
While in Florida, I had to press 2 for English.
It just isn't fair.