Thursday, September 30, 2010

Re: [Electric Boats] Power Boat Conversion

 

Stephan,


I hope you will not give up on the idea of converting your Trojan to electric propulsion.  As was true with my 26 Pacemaker; you will have challenges along the way; but what a feeling when you cruise with electric power.  I have emailed back & forth with a guy out on the west coast that has an older wooden fly bridge 32 footer that he converted to twin electric propulsion about 2 years ago and he loves it.  Cruises all over the place and now has installed a generator as well.  Such a great thing to do; convert an old powerboat with electric drives.  

John Raynes



On Thu, Sep 30, 2010 at 10:11 PM, quietboats <no_reply@yahoogroups.com> wrote:
 

Stephan, My advice is to read and understand the book "The Nature of Boats" by Dave Gerr--it is an easy read and full of great information on how different types of boats operate. Without background knowledge on basic hull performance principles you won't able able to fully comprehend and utilize the well meaning support and ideas of others.

You have a deep vee boat designed to run fast through rough water--in order to do that, that hull sacrifices ALL elements necesary for an efficient electric boat. So with that hull, one mile, maybe five miles, sure--expensive but doable. Twenty, thirty--never. Ever. Good luck. Tom



--- In electricboats@yahoogroups.com, Stephan Hinni <hinni_mb@...> wrote:
>
> Hi Eric
>
> The figures I sent you are for one engine only, sorry I forgot to mention that.
>
> Thanks for for your calculations, you explained it good and they make sense to me. But cheese, the outcome doesn't look very good for me, does it?
> I know it's not going to be an easy task that conversion, that's why I am here and ask for support and ideas.
>
> Thanks for your time and help Eric.
>
> Regards,
>
> Stephan
>
> --- On Tue, 9/28/10, Eric <ewdysar@...> wrote:
>
> From: Eric <ewdysar@...>
> Subject: Re: [Electric Boats] Power Boat Conversion
> To: electricboats@yahoogroups.com
> Date: Tuesday, September 28, 2010, 5:00 PM
>
>
>
>
>
>
>
>  

>
>
>
>
>
>
>
>
>
> Stephan,
>
>
>
> From your answer, I don't know if these figures are for each engine or for both, but you can adjust my answer accordingly.
>
>
>
> Assuming a thermal efficiency of only 20% because of low throttle settings, a reading of 3.3gph works out to 29.2hp delivered at the engine crankshaft(s). So figuring for 3.3gph for the boat at 6kts, you'll need 15hp from each motor to achieve the same speed. 15hp is 11,250W (15hp * 750W/hp), so your projected 10kW motors may be a little undersized. These figures aren't too far off of the 20kW that was estimated earlier.
>
>
>
> You can quickly see why large power boats run big engines, the hulls aren't very efficient, but hundreds of hp are pretty easy.
>
>
>
> However, that doesn't bode well for electric conversions. Once you find a suitable drive motor, using batteries for storage gets crazy pretty quickly. Using your figures, a 40 mile journey @ 6kts will burn about 22 gallons of gas. One gallon of gasoline through an IC engine is roughly equivalent to 10kWh of electricity through an electric drive. So your round trip would require more than 200kWh of usable battery capacity. Going high tech, Lithium Iron batteries are about half the weight and size of lead acid batteries and this trip would require more than 6000 pounds of LiFePO4 batteries that cost over $100,000. Lead Acid batteries would be somewhat cheaper, but come close to the weight of your boat in batteries alone.
>
>
>
> As you try to scale back to control costs and weight, you can see that $10,000/600lbs of LiFePO4 batteries will drive the boat at 6kts for only about 45 minutes before they're flat.
>
>
>
> All of these numbers are broad estimates, and you results would vary, but these numbers are close enough to seriously re-evaluate the overall feasability of the project. Imagine that your results turned out twice as good as my calcs, I think that the answers are still prohibitive.
>
>
>
> This shows again how electric is not a universal answer. It's is very well suited for some boats, but not very effective for others.
>
>
>
> Fair winds,
>
> Eric
>
> Marina del Rey, CA
>
>
>
> PS. before anyone questions the thermal efficiency value of only 20%, increasing that constant makes all of the numbers even worse...
>
>
>
> --- In electricboats@yahoogroups.com, Stephan Hinni <hinni_mb@> wrote:
>
> >
>
> > Hi Eric
>
> >
>
> > the gas flow meters would show me a reading of about 3.3 gal/hr at 6 kts and 3.8 gal/hr at 8 kts.
>
> >
>
> > Thanks for your support!
>
> >
>
> > Stephan
>
> >
>
> > --- On Mon, 9/27/10, Eric <ewdysar@> wrote:
>
> >
>
> > From: Eric <ewdysar@>
>
> > Subject: Re: [Electric Boats] Power Boat Conversion
>
> > To: electricboats@yahoogroups.com
>
> > Date: Monday, September 27, 2010, 11:31 PM
>
> >
>
> >
>
> > That figure may not be too far off. 20kW is less than 30hp at 100% efficiency. Even an electric drive will deliver only about 10hp to each prop with that amount of energy. Another way to estimate the power needed is to evaluate the fuel consumption.
>
> >
>
> > Stephan,
>
> >
>
> > Do you know the fuel consumption of your boat in gallons per hour at your target speeds of 6 to 8kts?
>
> >
>
> > Given that figure, I can back into the estimated hp that your boat needs to sustain that speed. From there, it's fairly easy to convert the ICE output to electric demand. While this process is not as accurate as a tow test, it should get you in the ballpark of what size drive would be appropriate. Of course, you'll probably want to add some reserve capacity to deal with adverse conditions.
>
> >
>
> > Fair winds,
>
> > Eric
>
> > Marina del Rey, CA
>
> >
>
> > > --- In electricboats@yahoogroups.com, Hans Rijnbout <jrijnb@> wrote:
>
> >
>
> > > > Stephan Hinni wrote:
>
> >
>
> > > >
>
> >
>
> > > > My idea is to use the yacht for scuba diving and pleasure trips. I'd
>
> >
>
> > > > like to cruise at 6 to 8 knots and have a daily range from 40
>
> >
>
> > > > nautical miles.
>
> >
>
> > > > I want to use two 10 kW Mars Motors and let them run at 72 Volts.
>
> >
>
> > > > Battery storage is no problem once the gas engines are out! The
>
> >
>
> > > > battery charging is at the slip (110V) and while navigating 4 Solar
>
> >
>
> > > > Panels bring in a bit of extra amperes. A gas generator is on board
>
> >
>
> > > > too but it have to be fixed first.
>
> >
>
> > > >
>
> >
>
> > > > The yacht is currently powered by 2 Chrysler 250HP gas engines. The
>
> >
>
> > > > length is 30.4 ft, breadth is 12.8 ft and she weights 16000 lbs. The
>
> >
>
> > > > propellers are 16RH16 and 16LH16 and the gear ratio is 1.52:1.
>
> >
>
> > > >
>
> >
>


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Re: [Electric Boats] Re: Tartan 27, setting up bearing

 

Sounds like that would work fine with robust tabbing.  The flange bearing is self aligning, that is the bearing should be on the correct centerline but the mounting plate does not have to be perfectly square to the shaft in the Y and Z axes.  You should try to get it as square as possible though.
 
Denny
 
----- Original Message -----
Sent: Thursday, September 30, 2010 10:00 PM
Subject: [Electric Boats] Re: Tartan 27, setting up bearing

 

Thanks everybody for all the thoughts and advice on the bearing.

It sounds like what I was planning to do might not be careful enough.

I was going to fabricate a transverse plate to hold the bearing and fit it loosely in the shaft alley, then mount the bearing into it off the shaft.

Then I was going to mark the current play in the shaft up, down, left, and right; find the center of that play, assume that was where I wanted the shaft to end up...then slide the bearing (already installed in the transverse plate) onto the shaft it and block the shaft at its "center of play" position. Then tab the plate to the hull.

Basically I would be hanging the bearing from the 1in shaft, with the shaft supported forward by blocks and aft by the cutlass bearing, until the epoxy cured.

I used a similar technique when I replaced my chainplate knees--hang the knee from the chainplate until the epoxy cures, to ensure that the knee (and the holes in it) were in the right place relative to the chainplate.

But I am concerned that bearings in the drivetrain need to have better alignment than the chainplate knees did.

I am also worried about doing this out of the water -- doesn't the boat change shape some between the water and the hard?

Thanks again, Paul

--- In electricboats@yahoogroups.com, "Tom" <boat_works@...> wrote:
>
>
>
> Most boats will have self-aligning stuffing boxes (or shaft seals). Just remove the stuffing box and shim the shaft to be centered in the shaft log. In most boats the unsupported shaft is adequately stiff to allow you to accurately place the thrust bearing.
>
> This assumes that you have the boat out of the water.
>
> It's really not difficult. I've shimmed shafts that only had 3/32" clearance between the shaft and the log without any trouble.
>
> -Tom
>
>
> --- In electricboats@yahoogroups.com, "John Green" <v_2jgree@> wrote:
> >
> > A way you can go when setting up a bearing is to have it mounted on a plate, with slots or oversized holes for adjustment of the flanged bearing.
> > Although my own personal choice would be to have 2 bearings, and universal joints and a short drive shaft to drive the actual prop shaft, but whether you have one or two, this setup will work.
> > The flanges are normally square. You position metal blocks welded on just clear of each of the 4 faces. They are drilled and tapped, and have bolts through them that can be adjusted to butt up against the bearing.
> > To set up a single bearing, you take a dial indicator, and place it in the vertical position. Set it to zero. Pull the shaft up to it's fullest top position, finding the normal position it would be in if the boat was upside down, that is, do not pull beyond a reasonable resting place. Take a reading of the dial gauge. Say it is 50 thousandths, then you adjust the screws in the appropriate block, in this case the bottom one, and raise the shaft/bearing up by 25 thousandths, then repeat the process for sideways play, pulling to one side, (like gravity did when doing the vertical one) zero out the dial, then pull the other way take a reading, set it up by splitting the difference of the two readings. then tighten the main holding bolts.
> > You can still do this without the blocks and screws, but they make it easier. They are also a way to maintain the bearing position if the main attachment bolts work loose, buying a bit of time. If you prefer not to have them, try pinching up the flange bolts hand tight, then tapping the bearing flange sides to move it in small increments once you have the readings.
> > A far better way is to have 2 dial indicators. Then you can be sure that one axis does not move when you are setting up the other. But you can manage with one if care is taken.
> > The idea behind this is that the shaft itself ends up in the centre of all the surrounding clearances that are currently there.
> > This info comes from experience as a machinist/millwright and may have snags due to the marine application, I have only just got into boats, so other group members might wish to correct errors/opinions.
> >
> > My own personal preference will be to separate the prop shaft, and have the drive through a short drive shaft. I am assuming that the prop shaft has two bearings, one each end of the tube. To have 3 of 4 total on the same shaft is mechanically unsound from a practical sense, particularly if the mountings are likely to flex, such as with a boat hull.
> > If that is the way you choose, you might be better with two plates to support the motor(s) and bearings, to enable side load without impacting the prop shaft.
> > Maybe also take a look at fabric universal joints such as are sometimes used in automotive steering on some older vehicles, they are forgiving, and would probably reduce vibration, and require less maintenance than regular UJ's, although of course there would be power limitations, however, they were used for the main drive on pre-war Fiat Topolino cars, so that would indicate a capability of at least 20HP.
> > I would also favour the motor(s) being mounted from behind, allowing easy access to the drive belts.
> >
> > --
> > _______________________________________________
> > Surf the Web in a faster, safer and easier way:
> > Download Opera 9 at http://www.opera.com
> >
>

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Posted by at No comments:

Re: [Electric Boats] Power Boat Conversion

 

Stephan, My advice is to read and understand the book "The Nature of Boats" by Dave Gerr--it is an easy read and full of great information on how different types of boats operate. Without background knowledge on basic hull performance principles you won't able able to fully comprehend and utilize the well meaning support and ideas of others.

You have a deep vee boat designed to run fast through rough water--in order to do that, that hull sacrifices ALL elements necesary for an efficient electric boat. So with that hull, one mile, maybe five miles, sure--expensive but doable. Twenty, thirty--never. Ever. Good luck. Tom

--- In electricboats@yahoogroups.com, Stephan Hinni <hinni_mb@...> wrote:
>
> Hi Eric
>
> The figures I sent you are for one engine only, sorry I forgot to mention that.
>
> Thanks for for your calculations, you explained it good and they make sense to me. But cheese, the outcome doesn't look very good for me, does it?
> I know it's not going to be an easy task that conversion, that's why I am here and ask for support and ideas.
>
> Thanks for your time and help Eric.
>
> Regards,
>
> Stephan
>
> --- On Tue, 9/28/10, Eric <ewdysar@...> wrote:
>
> From: Eric <ewdysar@...>
> Subject: Re: [Electric Boats] Power Boat Conversion
> To: electricboats@yahoogroups.com
> Date: Tuesday, September 28, 2010, 5:00 PM
>
>
>
>
>
>
>
>  
>
>
>
>
>
>
>
>
>
> Stephan,
>
>
>
> From your answer, I don't know if these figures are for each engine or for both, but you can adjust my answer accordingly.
>
>
>
> Assuming a thermal efficiency of only 20% because of low throttle settings, a reading of 3.3gph works out to 29.2hp delivered at the engine crankshaft(s). So figuring for 3.3gph for the boat at 6kts, you'll need 15hp from each motor to achieve the same speed. 15hp is 11,250W (15hp * 750W/hp), so your projected 10kW motors may be a little undersized. These figures aren't too far off of the 20kW that was estimated earlier.
>
>
>
> You can quickly see why large power boats run big engines, the hulls aren't very efficient, but hundreds of hp are pretty easy.
>
>
>
> However, that doesn't bode well for electric conversions. Once you find a suitable drive motor, using batteries for storage gets crazy pretty quickly. Using your figures, a 40 mile journey @ 6kts will burn about 22 gallons of gas. One gallon of gasoline through an IC engine is roughly equivalent to 10kWh of electricity through an electric drive. So your round trip would require more than 200kWh of usable battery capacity. Going high tech, Lithium Iron batteries are about half the weight and size of lead acid batteries and this trip would require more than 6000 pounds of LiFePO4 batteries that cost over $100,000. Lead Acid batteries would be somewhat cheaper, but come close to the weight of your boat in batteries alone.
>
>
>
> As you try to scale back to control costs and weight, you can see that $10,000/600lbs of LiFePO4 batteries will drive the boat at 6kts for only about 45 minutes before they're flat.
>
>
>
> All of these numbers are broad estimates, and you results would vary, but these numbers are close enough to seriously re-evaluate the overall feasability of the project. Imagine that your results turned out twice as good as my calcs, I think that the answers are still prohibitive.
>
>
>
> This shows again how electric is not a universal answer. It's is very well suited for some boats, but not very effective for others.
>
>
>
> Fair winds,
>
> Eric
>
> Marina del Rey, CA
>
>
>
> PS. before anyone questions the thermal efficiency value of only 20%, increasing that constant makes all of the numbers even worse...
>
>
>
> --- In electricboats@yahoogroups.com, Stephan Hinni <hinni_mb@> wrote:
>
> >
>
> > Hi Eric
>
> >
>
> > the gas flow meters would show me a reading of about 3.3 gal/hr at 6 kts and 3.8 gal/hr at 8 kts.
>
> >
>
> > Thanks for your support!
>
> >
>
> > Stephan
>
> >
>
> > --- On Mon, 9/27/10, Eric <ewdysar@> wrote:
>
> >
>
> > From: Eric <ewdysar@>
>
> > Subject: Re: [Electric Boats] Power Boat Conversion
>
> > To: electricboats@yahoogroups.com
>
> > Date: Monday, September 27, 2010, 11:31 PM
>
> >
>
> >
>
> > That figure may not be too far off. 20kW is less than 30hp at 100% efficiency. Even an electric drive will deliver only about 10hp to each prop with that amount of energy. Another way to estimate the power needed is to evaluate the fuel consumption.
>
> >
>
> > Stephan,
>
> >
>
> > Do you know the fuel consumption of your boat in gallons per hour at your target speeds of 6 to 8kts?
>
> >
>
> > Given that figure, I can back into the estimated hp that your boat needs to sustain that speed. From there, it's fairly easy to convert the ICE output to electric demand. While this process is not as accurate as a tow test, it should get you in the ballpark of what size drive would be appropriate. Of course, you'll probably want to add some reserve capacity to deal with adverse conditions.
>
> >
>
> > Fair winds,
>
> > Eric
>
> > Marina del Rey, CA
>
> >
>
> > > --- In electricboats@yahoogroups.com, Hans Rijnbout <jrijnb@> wrote:
>
> >
>
> > > > Stephan Hinni wrote:
>
> >
>
> > > >
>
> >
>
> > > > My idea is to use the yacht for scuba diving and pleasure trips. I'd
>
> >
>
> > > > like to cruise at 6 to 8 knots and have a daily range from 40
>
> >
>
> > > > nautical miles.
>
> >
>
> > > > I want to use two 10 kW Mars Motors and let them run at 72 Volts.
>
> >
>
> > > > Battery storage is no problem once the gas engines are out! The
>
> >
>
> > > > battery charging is at the slip (110V) and while navigating 4 Solar
>
> >
>
> > > > Panels bring in a bit of extra amperes. A gas generator is on board
>
> >
>
> > > > too but it have to be fixed first.
>
> >
>
> > > >
>
> >
>
> > > > The yacht is currently powered by 2 Chrysler 250HP gas engines. The
>
> >
>
> > > > length is 30.4 ft, breadth is 12.8 ft and she weights 16000 lbs. The
>
> >
>
> > > > propellers are 16RH16 and 16LH16 and the gear ratio is 1.52:1.
>
> >
>
> > > >
>
> >
>

__._,_.___
Recent Activity:
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__,_._,___
Posted by at No comments:

[Electric Boats] Re: Tartan 27, setting up bearing

 

Thanks everybody for all the thoughts and advice on the bearing.

It sounds like what I was planning to do might not be careful enough.

I was going to fabricate a transverse plate to hold the bearing and fit it loosely in the shaft alley, then mount the bearing into it off the shaft.

Then I was going to mark the current play in the shaft up, down, left, and right; find the center of that play, assume that was where I wanted the shaft to end up...then slide the bearing (already installed in the transverse plate) onto the shaft it and block the shaft at its "center of play" position. Then tab the plate to the hull.

Basically I would be hanging the bearing from the 1in shaft, with the shaft supported forward by blocks and aft by the cutlass bearing, until the epoxy cured.

I used a similar technique when I replaced my chainplate knees--hang the knee from the chainplate until the epoxy cures, to ensure that the knee (and the holes in it) were in the right place relative to the chainplate.

But I am concerned that bearings in the drivetrain need to have better alignment than the chainplate knees did.

I am also worried about doing this out of the water -- doesn't the boat change shape some between the water and the hard?

Thanks again, Paul

--- In electricboats@yahoogroups.com, "Tom" <boat_works@...> wrote:
>
>
>
> Most boats will have self-aligning stuffing boxes (or shaft seals). Just remove the stuffing box and shim the shaft to be centered in the shaft log. In most boats the unsupported shaft is adequately stiff to allow you to accurately place the thrust bearing.
>
> This assumes that you have the boat out of the water.
>
> It's really not difficult. I've shimmed shafts that only had 3/32" clearance between the shaft and the log without any trouble.
>
> -Tom
>
>
> --- In electricboats@yahoogroups.com, "John Green" <v_2jgree@> wrote:
> >
> > A way you can go when setting up a bearing is to have it mounted on a plate, with slots or oversized holes for adjustment of the flanged bearing.
> > Although my own personal choice would be to have 2 bearings, and universal joints and a short drive shaft to drive the actual prop shaft, but whether you have one or two, this setup will work.
> > The flanges are normally square. You position metal blocks welded on just clear of each of the 4 faces. They are drilled and tapped, and have bolts through them that can be adjusted to butt up against the bearing.
> > To set up a single bearing, you take a dial indicator, and place it in the vertical position. Set it to zero. Pull the shaft up to it's fullest top position, finding the normal position it would be in if the boat was upside down, that is, do not pull beyond a reasonable resting place. Take a reading of the dial gauge. Say it is 50 thousandths, then you adjust the screws in the appropriate block, in this case the bottom one, and raise the shaft/bearing up by 25 thousandths, then repeat the process for sideways play, pulling to one side, (like gravity did when doing the vertical one) zero out the dial, then pull the other way take a reading, set it up by splitting the difference of the two readings. then tighten the main holding bolts.
> > You can still do this without the blocks and screws, but they make it easier. They are also a way to maintain the bearing position if the main attachment bolts work loose, buying a bit of time. If you prefer not to have them, try pinching up the flange bolts hand tight, then tapping the bearing flange sides to move it in small increments once you have the readings.
> > A far better way is to have 2 dial indicators. Then you can be sure that one axis does not move when you are setting up the other. But you can manage with one if care is taken.
> > The idea behind this is that the shaft itself ends up in the centre of all the surrounding clearances that are currently there.
> > This info comes from experience as a machinist/millwright and may have snags due to the marine application, I have only just got into boats, so other group members might wish to correct errors/opinions.
> >
> > My own personal preference will be to separate the prop shaft, and have the drive through a short drive shaft. I am assuming that the prop shaft has two bearings, one each end of the tube. To have 3 of 4 total on the same shaft is mechanically unsound from a practical sense, particularly if the mountings are likely to flex, such as with a boat hull.
> > If that is the way you choose, you might be better with two plates to support the motor(s) and bearings, to enable side load without impacting the prop shaft.
> > Maybe also take a look at fabric universal joints such as are sometimes used in automotive steering on some older vehicles, they are forgiving, and would probably reduce vibration, and require less maintenance than regular UJ's, although of course there would be power limitations, however, they were used for the main drive on pre-war Fiat Topolino cars, so that would indicate a capability of at least 20HP.
> > I would also favour the motor(s) being mounted from behind, allowing easy access to the drive belts.
> >
> > --
> > _______________________________________________
> > Surf the Web in a faster, safer and easier way:
> > Download Opera 9 at http://www.opera.com
> >
>

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[Electric Boats] Re: Power Boat Conversion

 

Stephan,

Most of the larger conversions that I've seen are replacing engines up to the 20-30hp range. A couple of people have replaced 50hp engines with some success. But higher power systems require more storage and the numbers can quickly get out of hand.

You can see that replacing 500hp of IC power is a pretty tall order. Conversely, imagine mounting a 40hp outboard on the back of your boat. Do you think that it would still hit 6kts? Electric drives excel at slow and steady, high power generally means less range.

Good luck,
Eric
Marina del Rey, CA

--- In electricboats@yahoogroups.com, Stephan Hinni <hinni_mb@...> wrote:
>
> Hi Eric
>
> The figures I sent you are for one engine only, sorry I forgot to mention that.
>
> Thanks for for your calculations, you explained it good and they make sense to me. But cheese, the outcome doesn't look very good for me, does it?
> I know it's not going to be an easy task that conversion, that's why I am here and ask for support and ideas.
>
> Thanks for your time and help Eric.
>
> Regards,
>
> Stephan
>
> --- On Tue, 9/28/10, Eric <ewdysar@...> wrote:
>
> From: Eric <ewdysar@...>
> Subject: Re: [Electric Boats] Power Boat Conversion
> To: electricboats@yahoogroups.com
> Date: Tuesday, September 28, 2010, 5:00 PM
>
> Stephan,
>
> From your answer, I don't know if these figures are for each engine or for both, but you can adjust my answer accordingly.
>
> Assuming a thermal efficiency of only 20% because of low throttle settings, a reading of 3.3gph works out to 29.2hp delivered at the engine crankshaft(s). So figuring for 3.3gph for the boat at 6kts, you'll need 15hp from each motor to achieve the same speed. 15hp is 11,250W (15hp * 750W/hp), so your projected 10kW motors may be a little undersized. These figures aren't too far off of the 20kW that was estimated earlier.
>
> You can quickly see why large power boats run big engines, the hulls aren't very efficient, but hundreds of hp are pretty easy.
>
> However, that doesn't bode well for electric conversions. Once you find a suitable drive motor, using batteries for storage gets crazy pretty quickly. Using your figures, a 40 mile journey @ 6kts will burn about 22 gallons of gas. One gallon of gasoline through an IC engine is roughly equivalent to 10kWh of electricity through an electric drive. So your round trip would require more than 200kWh of usable battery capacity. Going high tech, Lithium Iron batteries are about half the weight and size of lead acid batteries and this trip would require more than 6000 pounds of LiFePO4 batteries that cost over $100,000. Lead Acid batteries would be somewhat cheaper, but come close to the weight of your boat in batteries alone.
>
> As you try to scale back to control costs and weight, you can see that $10,000/600lbs of LiFePO4 batteries will drive the boat at 6kts for only about 45 minutes before they're flat.
>
> All of these numbers are broad estimates, and you results would vary, but these numbers are close enough to seriously re-evaluate the overall feasability of the project. Imagine that your results turned out twice as good as my calcs, I think that the answers are still prohibitive.
>
> This shows again how electric is not a universal answer. It's is very well suited for some boats, but not very effective for others.
>
> Fair winds,
>
> Eric
>
> Marina del Rey, CA
>
> PS. before anyone questions the thermal efficiency value of only 20%, increasing that constant makes all of the numbers even worse...
>

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RE: [Electric Boats] Power Boat Conversion

 

It's easy Stephan: With an EV, you can have range, speed or low cost----pick any two.

In your case, you "need" all 3 and so it's a costly proposition and possibly untenable.

-mt

 

From: electricboats@yahoogroups.com [mailto:electricboats@yahoogroups.com] On Behalf Of Stephan Hinni
Sent: Thursday, September 30, 2010 9:40 AM
To: electricboats@yahoogroups.com
Subject: Re: [Electric Boats] Power Boat Conversion

 

 

Hi Eric

The figures I sent you are for one engine only, sorry I forgot to mention that.

Thanks for for your calculations, you explained it good and they make sense to me. But cheese, the outcome doesn't look very good for me, does it?
I know it's not going to be an easy task that conversion, that's why I am here and ask for support and ideas.

Thanks for your time and help Eric.

Regards,

Stephan

--- On Tue, 9/28/10, Eric <ewdysar@yahoo.com> wrote:


From: Eric <ewdysar@yahoo.com>
Subject: Re: [Electric Boats] Power Boat Conversion
To: electricboats@yahoogroups.com
Date: Tuesday, September 28, 2010, 5:00 PM

 

Stephan,

From your answer, I don't know if these figures are for each engine or for both, but you can adjust my answer accordingly.

Assuming a thermal efficiency of only 20% because of low throttle settings, a reading of 3.3gph works out to 29.2hp delivered at the engine crankshaft(s). So figuring for 3.3gph for the boat at 6kts, you'll need 15hp from each motor to achieve the same speed. 15hp is 11,250W (15hp * 750W/hp), so your projected 10kW motors may be a little undersized. These figures aren't too far off of the 20kW that was estimated earlier.

You can quickly see why large power boats run big engines, the hulls aren't very efficient, but hundreds of hp are pretty easy.

However, that doesn't bode well for electric conversions. Once you find a suitable drive motor, using batteries for storage gets crazy pretty quickly. Using your figures, a 40 mile journey @ 6kts will burn about 22 gallons of gas. One gallon of gasoline through an IC engine is roughly equivalent to 10kWh of electricity through an electric drive. So your round trip would require more than 200kWh of usable battery capacity. Going high tech, Lithium Iron batteries are about half the weight and size of lead acid batteries and this trip would require more than 6000 pounds of LiFePO4 batteries that cost over $100,000. Lead Acid batteries would be somewhat cheaper, but come close to the weight of your boat in batteries alone.

As you try to scale back to control costs and weight, you can see that $10,000/600lbs of LiFePO4 batteries will drive the boat at 6kts for only about 45 minutes before they're flat.

All of these numbers are broad estimates, and you results would vary, but these numbers are close enough to seriously re-evaluate the overall feasability of the project. Imagine that your results turned out twice as good as my calcs, I think that the answers are still prohibitive.

This shows again how electric is not a universal answer. It's is very well suited for some boats, but not very effective for others.

Fair winds,
Eric
Marina del Rey, CA

PS. before anyone questions the thermal efficiency value of only 20%, increasing that constant makes all of the numbers even worse...

--- In electricboats@yahoogroups.com, Stephan Hinni <hinni_mb@...> wrote:
>
> Hi Eric
>
> the gas flow meters would show me a reading of about 3.3 gal/hr at 6 kts and 3.8 gal/hr at 8 kts.
>
> Thanks for your support!
>
> Stephan
>
> --- On Mon, 9/27/10, Eric <ewdysar@...> wrote:
>
> From: Eric <ewdysar@...>
> Subject: Re: [Electric Boats] Power Boat Conversion
> To: electricboats@yahoogroups.com
> Date: Monday, September 27, 2010, 11:31 PM
>
>
> That figure may not be too far off. 20kW is less than 30hp at 100% efficiency. Even an electric drive will deliver only about 10hp to each prop with that amount of energy. Another way to estimate the power needed is to evaluate the fuel consumption.
>
> Stephan,
>
> Do you know the fuel consumption of your boat in gallons per hour at your target speeds of 6 to 8kts?
>
> Given that figure, I can back into the estimated hp that your boat needs to sustain that speed. From there, it's fairly easy to convert the ICE output to electric demand. While this process is not as accurate as a tow test, it should get you in the ballpark of what size drive would be appropriate. Of course, you'll probably want to add some reserve capacity to deal with adverse conditions.
>
> Fair winds,
> Eric
> Marina del Rey, CA
>
> > --- In electricboats@yahoogroups.com, Hans Rijnbout <jrijnb@> wrote:
>
> > > Stephan Hinni wrote:
>
> > >
>
> > > My idea is to use the yacht for scuba diving and pleasure trips. I'd
>
> > > like to cruise at 6 to 8 knots and have a daily range from 40
>
> > > nautical miles.
>
> > > I want to use two 10 kW Mars Motors and let them run at 72 Volts.
>
> > > Battery storage is no problem once the gas engines are out! The
>
> > > battery charging is at the slip (110V) and while navigating 4 Solar
>
> > > Panels bring in a bit of extra amperes. A gas generator is on board
>
> > > too but it have to be fixed first.
>
> > >
>
> > > The yacht is currently powered by 2 Chrysler 250HP gas engines. The
>
> > > length is 30.4 ft, breadth is 12.8 ft and she weights 16000 lbs. The
>
> > > propellers are 16RH16 and 16LH16 and the gear ratio is 1.52:1.
>
> > >
>

 

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[Electric Boats] Re: Looking for assistance in conversion project

 

Hey James,

I'm glad to hear that you worked past the melted wires, your controllerless configuration and got your Kelly controller working. Since your project is a little different than most on this board, do you mind sharing some of your test results? The 2 pictures of your boat that I found on this board do show a good looking boat, but nothing about the conversion aspect.

Fair winds,
Eric
Marina del Rey, CA

PS. Is your next project still the 32' Trojan Sportfisher?

--- In electricboats@yahoogroups.com, "james4078" <james4078@...> wrote:
>
> Hey everyone
>
> I have finished my conversion and testing of the new electric drive system in my small prototype electric jet boat.
> I am now looking to bring on some partners on a larger scale boat refit.
>
> I am looking for either equity partners or just investors that want to earn a better return on their money.
>
> Interested parties can email for more details, pictures are posted here of prototype boat.
>
> thanks
>
> James
>

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Re: [Electric Boats] Power Boat Conversion

 

Hi Eric

The figures I sent you are for one engine only, sorry I forgot to mention that.

Thanks for for your calculations, you explained it good and they make sense to me. But cheese, the outcome doesn't look very good for me, does it?
I know it's not going to be an easy task that conversion, that's why I am here and ask for support and ideas.

Thanks for your time and help Eric.

Regards,

Stephan

--- On Tue, 9/28/10, Eric <ewdysar@yahoo.com> wrote:

From: Eric <ewdysar@yahoo.com>
Subject: Re: [Electric Boats] Power Boat Conversion
To: electricboats@yahoogroups.com
Date: Tuesday, September 28, 2010, 5:00 PM

 

Stephan,

From your answer, I don't know if these figures are for each engine or for both, but you can adjust my answer accordingly.

Assuming a thermal efficiency of only 20% because of low throttle settings, a reading of 3.3gph works out to 29.2hp delivered at the engine crankshaft(s). So figuring for 3.3gph for the boat at 6kts, you'll need 15hp from each motor to achieve the same speed. 15hp is 11,250W (15hp * 750W/hp), so your projected 10kW motors may be a little undersized. These figures aren't too far off of the 20kW that was estimated earlier.

You can quickly see why large power boats run big engines, the hulls aren't very efficient, but hundreds of hp are pretty easy.

However, that doesn't bode well for electric conversions. Once you find a suitable drive motor, using batteries for storage gets crazy pretty quickly. Using your figures, a 40 mile journey @ 6kts will burn about 22 gallons of gas. One gallon of gasoline through an IC engine is roughly equivalent to 10kWh of electricity through an electric drive. So your round trip would require more than 200kWh of usable battery capacity. Going high tech, Lithium Iron batteries are about half the weight and size of lead acid batteries and this trip would require more than 6000 pounds of LiFePO4 batteries that cost over $100,000. Lead Acid batteries would be somewhat cheaper, but come close to the weight of your boat in batteries alone.

As you try to scale back to control costs and weight, you can see that $10,000/600lbs of LiFePO4 batteries will drive the boat at 6kts for only about 45 minutes before they're flat.

All of these numbers are broad estimates, and you results would vary, but these numbers are close enough to seriously re-evaluate the overall feasability of the project. Imagine that your results turned out twice as good as my calcs, I think that the answers are still prohibitive.

This shows again how electric is not a universal answer. It's is very well suited for some boats, but not very effective for others.

Fair winds,
Eric
Marina del Rey, CA

PS. before anyone questions the thermal efficiency value of only 20%, increasing that constant makes all of the numbers even worse...

--- In electricboats@yahoogroups.com, Stephan Hinni <hinni_mb@...> wrote:
>
> Hi Eric
>
> the gas flow meters would show me a reading of about 3.3 gal/hr at 6 kts and 3.8 gal/hr at 8 kts.
>
> Thanks for your support!
>
> Stephan
>
> --- On Mon, 9/27/10, Eric <ewdysar@...> wrote:
>
> From: Eric <ewdysar@...>
> Subject: Re: [Electric Boats] Power Boat Conversion
> To: electricboats@yahoogroups.com
> Date: Monday, September 27, 2010, 11:31 PM
>
>
> That figure may not be too far off. 20kW is less than 30hp at 100% efficiency. Even an electric drive will deliver only about 10hp to each prop with that amount of energy. Another way to estimate the power needed is to evaluate the fuel consumption.
>
> Stephan,
>
> Do you know the fuel consumption of your boat in gallons per hour at your target speeds of 6 to 8kts?
>
> Given that figure, I can back into the estimated hp that your boat needs to sustain that speed. From there, it's fairly easy to convert the ICE output to electric demand. While this process is not as accurate as a tow test, it should get you in the ballpark of what size drive would be appropriate. Of course, you'll probably want to add some reserve capacity to deal with adverse conditions.
>
> Fair winds,
> Eric
> Marina del Rey, CA
>
> > --- In electricboats@yahoogroups.com, Hans Rijnbout <jrijnb@> wrote:
>
> > > Stephan Hinni wrote:
>
> > >
>
> > > My idea is to use the yacht for scuba diving and pleasure trips. I'd
>
> > > like to cruise at 6 to 8 knots and have a daily range from 40
>
> > > nautical miles.
>
> > > I want to use two 10 kW Mars Motors and let them run at 72 Volts.
>
> > > Battery storage is no problem once the gas engines are out! The
>
> > > battery charging is at the slip (110V) and while navigating 4 Solar
>
> > > Panels bring in a bit of extra amperes. A gas generator is on board
>
> > > too but it have to be fixed first.
>
> > >
>
> > > The yacht is currently powered by 2 Chrysler 250HP gas engines. The
>
> > > length is 30.4 ft, breadth is 12.8 ft and she weights 16000 lbs. The
>
> > > propellers are 16RH16 and 16LH16 and the gear ratio is 1.52:1.
>
> > >
>


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Posted by at No comments:

[Electric Boats] Re: Tartan 27, setting up bearing

 

Yes, that is correct. The shaft is usually only supported by the Cutless bearing and the reduction gear.

Radial load on the shaft at the gearwheel seems pretty small with toothed belts, certainly not enough to be problem for a 1" diameter shaft closely supported by a thrust bearing.

I tension the belt by moving the motor in slotted mounting holes, as you mentioned. There is much less tension on this belt than on a water pump or alternator.

I have really come to appreciate the simplicity, reliability, and efficiency of the entire installation.

-Tom

--- In electricboats@yahoogroups.com, "John Green" <v_2jgree@...> wrote:
>
> Tom, Thanks. From what you say, there is only one bearing in a regular boat shaft, and that is the cutless or cutlass bearing at the prop end?
> That would make more mechanical sense, as the ICE transmission would form the other bearing. And would make my UJ idea useless, of course.
> Funny how all the books I have read don't make it clear that there is no top (inside) bearing, if that is in fact the case - I hope it is, because if so it just saved a load of future hassle and expense.
> In such a case, of course one bearing at the inside end would be OK provided that the side loads from belt tension were not too high, if a belt was used.
> My two bearing idea is overthinking this whole thing, I assume?
> In my own case, a New Horizons 26 (that was put out of business by the Tartan 27!) I intend trying multiple smaller and cheaper electric motors (to eliminate the controllers and provide the ability to build up the system over time), so I will be able to equalise the side loads by having the motors mounted by slots for adjustment onto a single metal plate, and belts from each one to the shaft pulleys, or preferably one long pulley with teeth. Might be able to use standard automotive parts, maybe recycled cam drives.
>
>
> John
>
> 3b. Re: Tartan 27, setting up bearing
> Posted by: "Tom" boat_works@... boat_works
> Date: Wed Sep 29, 2010 9:21 pm ((PDT))
>
>
>
> Most boats will have self-aligning stuffing boxes (or shaft seals).
> Just remove the stuffing box and shim the shaft to be centered in the
> shaft log. In most boats the unsupported shaft is adequately stiff to
> allow you to accurately place the thrust bearing.
>
> This assumes that you have the boat out of the water.
>
> It's really not difficult. I've shimmed shafts that only had 3/32"
> clearance between the shaft and the log without any trouble.
>
> -Tom
>
> --
> _______________________________________________
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