re-power

[CptnDon]

Can anyone here advise me about re-powering from a gas v8 to electric propulsion?

[CptnDon]

Can anyone here advise me about re-powering from a gas v8 to electric propulsion?

[CptnDon]

Can anyone here advise me about re-powering from a gas v8 to electric propulsion?

[nedL]

What kind of boat?? I think it's safe to say that performance will be no where similar, electric is pretty much for low speed easilly moved hulls.

[nedL]

What kind of boat?? I think it's safe to say that performance will be no where similar, electric is pretty much for low speed easilly moved hulls.

[nedL]

What kind of boat?? I think it's safe to say that performance will be no where similar, electric is pretty much for low speed easilly moved hulls.

[CptnDon]

The boat is a 1960 36' baybuilt(Chesapeake Bay) deadrise sedan fisherman. It weighs approx 16000 lbs.
I can't agree with the assumption that electric is only for lightweight slippery boats. What about trains, giant earth movers, and ships? Surely the technology to move a boat exists out there somewhere.

[CptnDon]

The boat is a 1960 36' baybuilt(Chesapeake Bay) deadrise sedan fisherman. It weighs approx 16000 lbs.
I can't agree with the assumption that electric is only for lightweight slippery boats. What about trains, giant earth movers, and ships? Surely the technology to move a boat exists out there somewhere.

[CptnDon]

The boat is a 1960 36' baybuilt(Chesapeake Bay) deadrise sedan fisherman. It weighs approx 16000 lbs.
I can't agree with the assumption that electric is only for lightweight slippery boats. What about trains, giant earth movers, and ships? Surely the technology to move a boat exists out there somewhere.

[Brian Palmer]

There was an article about electric power in a very recent issue of Professional Boatbuilder (the sister to Woodenboat). Check it out.

-- Brian

[Brian Palmer]

There was an article about electric power in a very recent issue of Professional Boatbuilder (the sister to Woodenboat). Check it out.

-- Brian

[Brian Palmer]

There was an article about electric power in a very recent issue of Professional Boatbuilder (the sister to Woodenboat). Check it out.

-- Brian

[nedL]

I agree that electric moves some pretty big stuff, but I think that's usually either diesel-electric (trains, ships [even QM2 I believe])or straight electric where there is a supply system(trains, subways) with overhead lines or third rail. In these situations you have either big diesel engine generators to provide the power or a hard connection back to the generating source.
I believe the advantages of diesel-electric (esp. in trains) is the low speed driving torgue that is available, not economy or efficiency. An electric motor develops lots of torque at zero RPM, which is needed to get the train moving (can't do that with straight diesel, it will either stall or burn out lots of clutches). I'll have to stick with my initial assertion that when you are restricted electric running off some sort of an electrical storage system (presumably some type of batteries)you don't have the hp available for an extended period of time that is required to move a good size boat (36' deadrise) at a good speed (say 8+ knots). **Or at least not within a budget that most would consider reasonable.

[nedL]

I agree that electric moves some pretty big stuff, but I think that's usually either diesel-electric (trains, ships [even QM2 I believe])or straight electric where there is a supply system(trains, subways) with overhead lines or third rail. In these situations you have either big diesel engine generators to provide the power or a hard connection back to the generating source.
I believe the advantages of diesel-electric (esp. in trains) is the low speed driving torgue that is available, not economy or efficiency. An electric motor develops lots of torque at zero RPM, which is needed to get the train moving (can't do that with straight diesel, it will either stall or burn out lots of clutches). I'll have to stick with my initial assertion that when you are restricted electric running off some sort of an electrical storage system (presumably some type of batteries)you don't have the hp available for an extended period of time that is required to move a good size boat (36' deadrise) at a good speed (say 8+ knots). **Or at least not within a budget that most would consider reasonable.

[nedL]

I agree that electric moves some pretty big stuff, but I think that's usually either diesel-electric (trains, ships [even QM2 I believe])or straight electric where there is a supply system(trains, subways) with overhead lines or third rail. In these situations you have either big diesel engine generators to provide the power or a hard connection back to the generating source.
I believe the advantages of diesel-electric (esp. in trains) is the low speed driving torgue that is available, not economy or efficiency. An electric motor develops lots of torque at zero RPM, which is needed to get the train moving (can't do that with straight diesel, it will either stall or burn out lots of clutches). I'll have to stick with my initial assertion that when you are restricted electric running off some sort of an electrical storage system (presumably some type of batteries)you don't have the hp available for an extended period of time that is required to move a good size boat (36' deadrise) at a good speed (say 8+ knots). **Or at least not within a budget that most would consider reasonable.

[cbob]

Don, Trains, Ships etc. use Steam or Gas Turbine or Diesael Electric, third rail power supply etc. For the power and independence you will probably need is a Diesel or gasoline engine driven generator set with an electric motor on the end of the propeller shaft. The advantage of this setup is the generator can be located remotly from the motor. There are Diesel Hydraulic options that are even less efficient than Diesel Electric, or a very long large drop cord. cbob

[cbob]

Don, Trains, Ships etc. use Steam or Gas Turbine or Diesael Electric, third rail power supply etc. For the power and independence you will probably need is a Diesel or gasoline engine driven generator set with an electric motor on the end of the propeller shaft. The advantage of this setup is the generator can be located remotly from the motor. There are Diesel Hydraulic options that are even less efficient than Diesel Electric, or a very long large drop cord. cbob

[cbob]

Don, Trains, Ships etc. use Steam or Gas Turbine or Diesael Electric, third rail power supply etc. For the power and independence you will probably need is a Diesel or gasoline engine driven generator set with an electric motor on the end of the propeller shaft. The advantage of this setup is the generator can be located remotly from the motor. There are Diesel Hydraulic options that are even less efficient than Diesel Electric, or a very long large drop cord. cbob

[ahp]

Do a little math. One hp is 746 watts. A lead acid battery has about 15 to 20 watt hours per pound. This all assumes unrealistically, 100% efficiency. How many pounds of battery for the same hp for how long?

There are batteries with better specific energy than lead acid, but not enough better for what you are proposing. With batteries and electic motors you might reach the same speed as you could with the V8, but for a VERY short time.

[ahp]

Do a little math. One hp is 746 watts. A lead acid battery has about 15 to 20 watt hours per pound. This all assumes unrealistically, 100% efficiency. How many pounds of battery for the same hp for how long?

There are batteries with better specific energy than lead acid, but not enough better for what you are proposing. With batteries and electic motors you might reach the same speed as you could with the V8, but for a VERY short time.

[ahp]

Do a little math. One hp is 746 watts. A lead acid battery has about 15 to 20 watt hours per pound. This all assumes unrealistically, 100% efficiency. How many pounds of battery for the same hp for how long?

There are batteries with better specific energy than lead acid, but not enough better for what you are proposing. With batteries and electic motors you might reach the same speed as you could with the V8, but for a VERY short time.

[ssor]

I read somewhere that 1 gallon of gasoline can supply the same amount of energy as 1 ton of lead acid batteries. Would a diesel electric motor-generator system be lighter than diesel mechanical transmission system? 1 screw or dual drive? You have a very large vessel, the range is determined by the capacity of the propulsion system. (read Fuel tanks)

[ssor]

I read somewhere that 1 gallon of gasoline can supply the same amount of energy as 1 ton of lead acid batteries. Would a diesel electric motor-generator system be lighter than diesel mechanical transmission system? 1 screw or dual drive? You have a very large vessel, the range is determined by the capacity of the propulsion system. (read Fuel tanks)

[ssor]

I read somewhere that 1 gallon of gasoline can supply the same amount of energy as 1 ton of lead acid batteries. Would a diesel electric motor-generator system be lighter than diesel mechanical transmission system? 1 screw or dual drive? You have a very large vessel, the range is determined by the capacity of the propulsion system. (read Fuel tanks)

[CptnDon]

I guess I should have been more specific. What"s in the boat now is a Palmer(International Harvester) 345 cu.in. gas V8. The specs are:220hp@4000rpm/300ft.lbs.torque. It swings a 22x18 four blade prop. We cruise @2000rpm which gives 118hp/310ft.lbs. and 7kts.
One of the goals of re-powering is to find a smaller "package" since the engine box is a little too big for the cabin.
One idea is to use an electric motor on the prop shaft along with a small DC(?) genset.
Any suggestions?

[CptnDon]

I guess I should have been more specific. What"s in the boat now is a Palmer(International Harvester) 345 cu.in. gas V8. The specs are:220hp@4000rpm/300ft.lbs.torque. It swings a 22x18 four blade prop. We cruise @2000rpm which gives 118hp/310ft.lbs. and 7kts.
One of the goals of re-powering is to find a smaller "package" since the engine box is a little too big for the cabin.
One idea is to use an electric motor on the prop shaft along with a small DC(?) genset.
Any suggestions?

[CptnDon]

I guess I should have been more specific. What"s in the boat now is a Palmer(International Harvester) 345 cu.in. gas V8. The specs are:220hp@4000rpm/300ft.lbs.torque. It swings a 22x18 four blade prop. We cruise @2000rpm which gives 118hp/310ft.lbs. and 7kts.
One of the goals of re-powering is to find a smaller "package" since the engine box is a little too big for the cabin.
One idea is to use an electric motor on the prop shaft along with a small DC(?) genset.
Any suggestions?

[High C]

Originally posted by CptnDon:
...One idea is to use an electric motor on the prop shaft along with a small DC(?) genset.
Any suggestions?It would take a very large genset to keep up with the high demands of an electric propulsion motor, and the other electrical needs of the vessel.

I do think there is great potential for diesel/electric propulsion in motor yachts that also have gensets going all the time already. Instead of having a seperate diesel for propulsion, it would be possible to have one or maybe two gensets powering a bank of batteries which supplies electricity to an electric propulsion motor and all the other electric goodies on board. That's how the state of the art cruise ships do it these days. And trains, of course. I wonder on how small a vessel such an arrangement would be practical?

[High C]

Originally posted by CptnDon:
...One idea is to use an electric motor on the prop shaft along with a small DC(?) genset.
Any suggestions?It would take a very large genset to keep up with the high demands of an electric propulsion motor, and the other electrical needs of the vessel.

I do think there is great potential for diesel/electric propulsion in motor yachts that also have gensets going all the time already. Instead of having a seperate diesel for propulsion, it would be possible to have one or maybe two gensets powering a bank of batteries which supplies electricity to an electric propulsion motor and all the other electric goodies on board. That's how the state of the art cruise ships do it these days. And trains, of course. I wonder on how small a vessel such an arrangement would be practical?

[High C]

Originally posted by CptnDon:
...One idea is to use an electric motor on the prop shaft along with a small DC(?) genset.
Any suggestions?It would take a very large genset to keep up with the high demands of an electric propulsion motor, and the other electrical needs of the vessel.

I do think there is great potential for diesel/electric propulsion in motor yachts that also have gensets going all the time already. Instead of having a seperate diesel for propulsion, it would be possible to have one or maybe two gensets powering a bank of batteries which supplies electricity to an electric propulsion motor and all the other electric goodies on board. That's how the state of the art cruise ships do it these days. And trains, of course. I wonder on how small a vessel such an arrangement would be practical?

[Gary E]

Don,
Your post...
"I guess I should have been more specific. What"s in the boat now is a Palmer(International Harvester) 345 cu.in. gas V8. The specs are:220hp@4000rpm/300ft.lbs.torque. It swings a 22x18 four blade prop. We cruise @2000rpm which gives 118hp/310ft.lbs. and 7kts.
One of the goals of re-powering is to find a smaller "package" since the engine box is a little too big for the cabin.
One idea is to use an electric motor on the prop shaft along with a small DC(?) genset.
Any suggestions?"

For that boat to be using that motor and prop, I would bet you also have a reduction gear, most likely 2:1 Now as for your statement of 118HP at 2000RPM.. how do you know? Did you measure that?

Let me take a educated guess here and say that the DC drive you think will work will be several things...Extreemely expensive, inefficient, and take more space than the engine you now have.

To acomplish your goals of moderate speed, decent handeling, a smaller engine and box, and economy of operation look for a 4 clynder diesel. A 4-53 Detroit with aprox 100 HP..4 cyl Ford has slightly less at 80 ish or a 4 cyl Perkins. Any one of these engines can be installed with minimal alteration to the boat and probably use the same shaft and prop.

Good luck

[Gary E]

Don,
Your post...
"I guess I should have been more specific. What"s in the boat now is a Palmer(International Harvester) 345 cu.in. gas V8. The specs are:220hp@4000rpm/300ft.lbs.torque. It swings a 22x18 four blade prop. We cruise @2000rpm which gives 118hp/310ft.lbs. and 7kts.
One of the goals of re-powering is to find a smaller "package" since the engine box is a little too big for the cabin.
One idea is to use an electric motor on the prop shaft along with a small DC(?) genset.
Any suggestions?"

For that boat to be using that motor and prop, I would bet you also have a reduction gear, most likely 2:1 Now as for your statement of 118HP at 2000RPM.. how do you know? Did you measure that?

Let me take a educated guess here and say that the DC drive you think will work will be several things...Extreemely expensive, inefficient, and take more space than the engine you now have.

To acomplish your goals of moderate speed, decent handeling, a smaller engine and box, and economy of operation look for a 4 clynder diesel. A 4-53 Detroit with aprox 100 HP..4 cyl Ford has slightly less at 80 ish or a 4 cyl Perkins. Any one of these engines can be installed with minimal alteration to the boat and probably use the same shaft and prop.

Good luck

[Gary E]

Don,
Your post...
"I guess I should have been more specific. What"s in the boat now is a Palmer(International Harvester) 345 cu.in. gas V8. The specs are:220hp@4000rpm/300ft.lbs.torque. It swings a 22x18 four blade prop. We cruise @2000rpm which gives 118hp/310ft.lbs. and 7kts.
One of the goals of re-powering is to find a smaller "package" since the engine box is a little too big for the cabin.
One idea is to use an electric motor on the prop shaft along with a small DC(?) genset.
Any suggestions?"

For that boat to be using that motor and prop, I would bet you also have a reduction gear, most likely 2:1 Now as for your statement of 118HP at 2000RPM.. how do you know? Did you measure that?

Let me take a educated guess here and say that the DC drive you think will work will be several things...Extreemely expensive, inefficient, and take more space than the engine you now have.

To acomplish your goals of moderate speed, decent handeling, a smaller engine and box, and economy of operation look for a 4 clynder diesel. A 4-53 Detroit with aprox 100 HP..4 cyl Ford has slightly less at 80 ish or a 4 cyl Perkins. Any one of these engines can be installed with minimal alteration to the boat and probably use the same shaft and prop.

Good luck