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Here They Come
- Thread starter Foggy
- Start date
Foggy":3qtcpfjy said:Thanks, daninPA, for explaining how a grievance differs from an argument* -->
a set of propositions --> a point. For me, when 'points' contain mostly extremes they lose value and my interest.
Thanks for providing a ready example of sophistry and reductionism.
-----------------------------
For those not inclined to score points in a fabricated joust, I'd like to observe that multiple sources of energy for propulsion are welcome.
Every power source has trade-offs. It's best when we can assess each and make choices based on our circumstances, conditions, interests, and resources.
Pretending any motor is "green" with no environmental impact is wishful thinking. It has an impact -- the only difference is where and what is impacted.
They are almost here... but pricey. Believe the claims? Buy one and find out.
What better use for all that $$ you saved by not going anywhere during COVID?
Then tell me about it.
Aye.
What better use for all that $$ you saved by not going anywhere during COVID?
The all-electric X-Shore EELEX 8000 costs $150,000.
The beauty of the boats, 1 -- it's about 1/3 of the cost of gas, 2 -- it's extremely quiet. You don't even hear it when you're out, you hear the water, and then 3 -- basically there are no byproducts going into the water. ...it can travel up to 100 nautical hours and only takes 30 to 40 minutes to charge.
https://upnorthlive.com/news/local/all- ... ids-marina
Then tell me about it.
Aye.
Worried lithium-ion batteries aren't up to the job for electric motors and eboats?
OMG
Sodium (about 1/4 lb in a gallon of sea water) is being developed to replace lithium.
It's much more abundant, safer, close to Li on the periodic table... has great potential.
https://beta.nsf.gov/news/scientists-de ... technology
Imagine if solar panel energy, when improved, could charge sodium-ion marine
batteries limiting or obviating the need for shore power recharging.
Now that's something, for some, to look forward to!
Aye.
OMG
Sodium (about 1/4 lb in a gallon of sea water) is being developed to replace lithium.
It's much more abundant, safer, close to Li on the periodic table... has great potential.
https://beta.nsf.gov/news/scientists-de ... technology
Imagine if solar panel energy, when improved, could charge sodium-ion marine
batteries limiting or obviating the need for shore power recharging.
Now that's something, for some, to look forward to!
Aye.
One can build an electric boat for far less than the prices above. These are back of the napkin type of calculations. The number of batteries, will determine the speed and range, (I went with 240 amp hour 48 volt battery) The boat would need only about 6 hp to achieve about 5 mph. But went with 20 hp to give the "reserve" to buck wind and current.
Elco 48 volt, 20 HP electric motor about $7,000
Controls for above motor $500.
Materials to build narrow beam, 20' light weight very efficient boat in stitch and glue: $10,000: 3/8" bottom 1/4" hull sides and deck Brunyzeel Marine plywood. Cover bottom with laver of 1708 on outside, 6 oz on the inside of all of hull, and 6 0z on hull sides and deck. Epoxy used for the entire project.
Running gear about $2,000
48 volt 20 amp battery charger and monitor about $800
48 Volt. Ampere Time 100 amp hours about $2100 per battery
48 Volt EVO 120 amp hour battery about $1600 per battery
If you assemble your own cells/battery about $800 per 48 volt, 100 amp hour battery. There are cheaper batteries, but this is for proven batteries.
Figure about $23,000 if you jump in today--no fudge factor for the inflation or oil priced materials tomorrow.. Actually the cost may be a bit less.
Probably take about 500 hours construction time, based on a hull design like Sam Devlin's Curlew 20. The time will be very dependent on the skills of the builder. There would be a number of differences--including the engine under a center console, There could be any type of deck or house design.
Elco 48 volt, 20 HP electric motor about $7,000
Controls for above motor $500.
Materials to build narrow beam, 20' light weight very efficient boat in stitch and glue: $10,000: 3/8" bottom 1/4" hull sides and deck Brunyzeel Marine plywood. Cover bottom with laver of 1708 on outside, 6 oz on the inside of all of hull, and 6 0z on hull sides and deck. Epoxy used for the entire project.
Running gear about $2,000
48 volt 20 amp battery charger and monitor about $800
48 Volt. Ampere Time 100 amp hours about $2100 per battery
48 Volt EVO 120 amp hour battery about $1600 per battery
If you assemble your own cells/battery about $800 per 48 volt, 100 amp hour battery. There are cheaper batteries, but this is for proven batteries.
Figure about $23,000 if you jump in today--no fudge factor for the inflation or oil priced materials tomorrow.. Actually the cost may be a bit less.
Probably take about 500 hours construction time, based on a hull design like Sam Devlin's Curlew 20. The time will be very dependent on the skills of the builder. There would be a number of differences--including the engine under a center console, There could be any type of deck or house design.
Karl Konecny
Member
Bob,
I like your boat design but I think you will still have range issues. 240 amp-hour, 48 volts is only 11.5 kW-hours. Six hp is ~4.5 kW which would drain the battery in about 2.5 hours which does not give you much range at the slow speed.
I'v worked in electric boat propulsion (autonomous submarines) for 20 years. Energy storage is the issue.
The day will come when battery technology will improve and cost will decline to the point an all electric boat will rival a gas powered boat. (We do have to solve the charging problem as well).
Here is what I am contemplating: I use my 22' cruiser for offshore salmon fishing. I will keep my 90hp Suzuki for crossing the bar and traveling to and from the fishing grounds but replace my kicker with an electric thruster. I can troll all day (8 to 10 hours) at just a couple of hp so an appropriate 5 hp electric thruster would be just fine. I would need a 15 to 20 kW-hr battery but would choose a voltage in the 200 - 300 volt range which would keep wire sizes reasonable and there are plenty of very efficient BLDC motor controllers available for that voltage and current.
I could recharge those batteries easily overnight on a standard 30 amp 120 volt marine AC hook up.
Throw in a 300 volt to 12 volt converter and I would eliminate the need for a house battery.
And I would have silent trolling! Instant start-stop! Precise thrust control! But it would not be cheap . . .
I like your boat design but I think you will still have range issues. 240 amp-hour, 48 volts is only 11.5 kW-hours. Six hp is ~4.5 kW which would drain the battery in about 2.5 hours which does not give you much range at the slow speed.
I'v worked in electric boat propulsion (autonomous submarines) for 20 years. Energy storage is the issue.
The day will come when battery technology will improve and cost will decline to the point an all electric boat will rival a gas powered boat. (We do have to solve the charging problem as well).
Here is what I am contemplating: I use my 22' cruiser for offshore salmon fishing. I will keep my 90hp Suzuki for crossing the bar and traveling to and from the fishing grounds but replace my kicker with an electric thruster. I can troll all day (8 to 10 hours) at just a couple of hp so an appropriate 5 hp electric thruster would be just fine. I would need a 15 to 20 kW-hr battery but would choose a voltage in the 200 - 300 volt range which would keep wire sizes reasonable and there are plenty of very efficient BLDC motor controllers available for that voltage and current.
I could recharge those batteries easily overnight on a standard 30 amp 120 volt marine AC hook up.
Throw in a 300 volt to 12 volt converter and I would eliminate the need for a house battery.
And I would have silent trolling! Instant start-stop! Precise thrust control! But it would not be cheap . . .
From my friends in Sweden. The Candela C-8 C-8 hydrofoil electric boat.
Ad foils and the efficiency (and complexity) increase dramatically:
https://www.youtube.com/watch?v=m0fWO1KO8-E
For more details:
https://www.youtube.com/watch?v=OYVfmtEDr00
We are already in the future!
Ad foils and the efficiency (and complexity) increase dramatically:
https://www.youtube.com/watch?v=m0fWO1KO8-E
For more details:
https://www.youtube.com/watch?v=OYVfmtEDr00
We are already in the future!
Karl,
Thanks for the response. How much "efficiency" will the 20 hp motor have lets say putting out 3 HP--Is there a "Price to pay" for the larger reserve.
I agree that battery capacity is the weak link--and will continue to be for some time. On the other hand (entirely different animal because the water resistance is far greater than rolling plus air resistance of the car) electric cars have large battery packs which are not as proportionately as expensive.
I had chosen the 48 volts because of the motor voltage and a very proven marine motor. But your point is very well taken.
The Torqeedo has a little under 1KWH battery supposedly rated at about 3hp (I think that is over-rated) but will push the 22 25 and my 18' Caracal cat at 3 mph for about 6 miles. (and that use is obviously is far less than even 1 hp)
I guess that experimentation is would be key to make sure that the hull is as slippery as possible. My neighbor worked on this for some time using Prendle Cat hulls and about a 3 hP electric motor--but used FLA batteries--he finally gave up.''
There must be a goodly amount of knowledge in your field of efficiencies of the motors and batteries.
How would one of the "5 hp thrusters" work to propel the about 20' light weight boat? I would think it would be about half of the power required for a C dory 22???
Thanks,
Bob
Thanks for the response. How much "efficiency" will the 20 hp motor have lets say putting out 3 HP--Is there a "Price to pay" for the larger reserve.
I agree that battery capacity is the weak link--and will continue to be for some time. On the other hand (entirely different animal because the water resistance is far greater than rolling plus air resistance of the car) electric cars have large battery packs which are not as proportionately as expensive.
I had chosen the 48 volts because of the motor voltage and a very proven marine motor. But your point is very well taken.
The Torqeedo has a little under 1KWH battery supposedly rated at about 3hp (I think that is over-rated) but will push the 22 25 and my 18' Caracal cat at 3 mph for about 6 miles. (and that use is obviously is far less than even 1 hp)
I guess that experimentation is would be key to make sure that the hull is as slippery as possible. My neighbor worked on this for some time using Prendle Cat hulls and about a 3 hP electric motor--but used FLA batteries--he finally gave up.''
There must be a goodly amount of knowledge in your field of efficiencies of the motors and batteries.
How would one of the "5 hp thrusters" work to propel the about 20' light weight boat? I would think it would be about half of the power required for a C dory 22???
Thanks,
Bob
I had wondered about foils, but thought that there was too much power needed to get on foil--I was wrong! Foils at 16 knots (?MPH) and when on efficient foil speed uses less than half of power at starting to plane.
The links show a lot more of the technology than I had realized went into the Candela 8. Carbon fiber, about 3500 lbs all up for a 29' boat sleeping 2 adults and 2 children, in the C 7 when on foils the boat was using less than 1 KWH per nautical mile. (C 7 was an outboard powered with motor in the cowl and drive shaft and gearing losses. The C8 only has electric motors in the "pod" which is attached to the rudder foil. So it is very close to being silent.
Good time to pay for now of the C 8's for next year--only 300,000 Euro--which is very close to parity currently.
The factory has over 100 on order!
So we see that a it is "practical" if you have $300,000+ for a 29' electric boat!
The links show a lot more of the technology than I had realized went into the Candela 8. Carbon fiber, about 3500 lbs all up for a 29' boat sleeping 2 adults and 2 children, in the C 7 when on foils the boat was using less than 1 KWH per nautical mile. (C 7 was an outboard powered with motor in the cowl and drive shaft and gearing losses. The C8 only has electric motors in the "pod" which is attached to the rudder foil. So it is very close to being silent.
Good time to pay for now of the C 8's for next year--only 300,000 Euro--which is very close to parity currently.
The factory has over 100 on order!
So we see that a it is "practical" if you have $300,000+ for a 29' electric boat!
Karl Konecny
Member
Bob,
Good questions with no easy answer. With a good 3 ph brushless DC motor design there is only a small penalty in efficiency in running a 20 hp motor at a 3 hp point. The bigger question is what is the advantage of having all that reserve hp. Power required goes up as the cube of boat speed (displacement mode) so doubling the speed requires eight times the power. At 20 hp you would drain your battery is very short order, about 45 minutes, which would give you very short range. I think the arguments that you need to excess power to overcome strong tidal current or wind don't pan out. With an electric boat you need to think more like a sailor -- don't fight the tide.
The Candela hydro-foil craft is an interesting example. They state it requires 25 kW to keep the boat flying. We know it takes much more than that to transition from planing to flying. Their motor is a 55 kW motor so they must have very little power to spare getting up on foil, a good design. Note they have a 44kW-hr battery so they an only fly for a bit over 1.5 hours, much less if you want to maintain reserve power for the unexpected. But the Candela does achieve amazing speed.
One frustration in this propulsion business is that there is so little data about propulsion components. Traditional outboards are rated at a max horsepower at max rpm. Very hard to get information out efficiency at different speeds and throttle settings. Electric trolling motors usually give a thrust spec at full revs and zero speed but very little data on actually power and thrust vs. hull speed. And hull designers do not publish much about hull resistance vs. speed. Propeller manufactures give even less data about their designs. Where are the thrust vs. input power and rpm vs. hull speed curves?
The submarine thrusters I work with are exceptional for thrust at low hull speeds. Most don't work well on surface boats because of cavitation problems which go away at depth pressure. But in reality they are just a different propeller design, higher speed, higher thrust.
I was impressed with the custom Candela motor/thruster although I question the decision to not have it oil filled. Shaft seals are good but there is enough crap floating around in coastal and inland waters (fishing line, . . .) that can cause seal problems. At least an oil filled motor will resist water intrusion and allow operation with a leak for awhile. Electric motor parts cannot be corrosion resistant. Oil filled motors do lose some efficiency (not much) but the reliability is worth it. Maybe Candela seals off the electric portion of the motor but that also will reduce efficiency (again not by much). I assume their engineers have thought of all of this and have made a calculated decision but I lean toward oil filled motors.
At this point in time I feel electric boat propulsion is ideal (but more costly) for someone on a "small" lake with their own dock (and charger) that uses the boat for short sunset cruises or trolling. But I do believe the improving technology will take over in the future.
Good questions with no easy answer. With a good 3 ph brushless DC motor design there is only a small penalty in efficiency in running a 20 hp motor at a 3 hp point. The bigger question is what is the advantage of having all that reserve hp. Power required goes up as the cube of boat speed (displacement mode) so doubling the speed requires eight times the power. At 20 hp you would drain your battery is very short order, about 45 minutes, which would give you very short range. I think the arguments that you need to excess power to overcome strong tidal current or wind don't pan out. With an electric boat you need to think more like a sailor -- don't fight the tide.
The Candela hydro-foil craft is an interesting example. They state it requires 25 kW to keep the boat flying. We know it takes much more than that to transition from planing to flying. Their motor is a 55 kW motor so they must have very little power to spare getting up on foil, a good design. Note they have a 44kW-hr battery so they an only fly for a bit over 1.5 hours, much less if you want to maintain reserve power for the unexpected. But the Candela does achieve amazing speed.
One frustration in this propulsion business is that there is so little data about propulsion components. Traditional outboards are rated at a max horsepower at max rpm. Very hard to get information out efficiency at different speeds and throttle settings. Electric trolling motors usually give a thrust spec at full revs and zero speed but very little data on actually power and thrust vs. hull speed. And hull designers do not publish much about hull resistance vs. speed. Propeller manufactures give even less data about their designs. Where are the thrust vs. input power and rpm vs. hull speed curves?
The submarine thrusters I work with are exceptional for thrust at low hull speeds. Most don't work well on surface boats because of cavitation problems which go away at depth pressure. But in reality they are just a different propeller design, higher speed, higher thrust.
I was impressed with the custom Candela motor/thruster although I question the decision to not have it oil filled. Shaft seals are good but there is enough crap floating around in coastal and inland waters (fishing line, . . .) that can cause seal problems. At least an oil filled motor will resist water intrusion and allow operation with a leak for awhile. Electric motor parts cannot be corrosion resistant. Oil filled motors do lose some efficiency (not much) but the reliability is worth it. Maybe Candela seals off the electric portion of the motor but that also will reduce efficiency (again not by much). I assume their engineers have thought of all of this and have made a calculated decision but I lean toward oil filled motors.
At this point in time I feel electric boat propulsion is ideal (but more costly) for someone on a "small" lake with their own dock (and charger) that uses the boat for short sunset cruises or trolling. But I do believe the improving technology will take over in the future.
Now we're gettin' somewhere. Foils yet. Be there in a minute...
Less energy, more speed.
But you don't have to be a speed freak. Want less speed and still
be able to beach your foiled eboat? The answer: retractable foils.
https://www.boatsnews.com/story/24381/t ... able-foils
I have to ask Harvey: Dream about a mega solar recharging eboat with retractable
foils? What would such a dream be: day, false awakening, healing, prophetic, a
nightmare (for some), or wet (it's a boat, yes)?
Aye.
Less energy, more speed.
But you don't have to be a speed freak. Want less speed and still
be able to beach your foiled eboat? The answer: retractable foils.
https://www.boatsnews.com/story/24381/t ... able-foils
I have to ask Harvey: Dream about a mega solar recharging eboat with retractable
foils? What would such a dream be: day, false awakening, healing, prophetic, a
nightmare (for some), or wet (it's a boat, yes)?
Aye.
Karl Konecny
Member
I'm certainly not a speed freak, there is reason my boat is named "Nowhere Fast"
thataway":3qlup99w said:... So we see that a it is "practical" if you have $300,000+ for a 29' electric boat!
I guess those people will have plenty of money for foil repairs after hitting debris in the water at speed.
Foils in the past have had a problem with foils and surface debris. I can remember seeing a Navy foiling ship in the Long Beach Area over 40 years ago. I believe it was run by gas turbines, I also heard that the design was not developed because of the issue hitting debris. I did ride in a foil boat in Sydney Australia in the 80's, so foil boats have been around for a long time. First hydrofoil was in 1906.
Thanks for the further information.
The Canela 8 has the forward foils retractable above the water line. The retractable "garage" is also where the step in the hull is which helps get the boat on plane. Also there is a very sophisticated computer on the Canela 8 with multiple sensors to make hundreds of adjustments of foil angle and Dept a minute.
'
The Pegasus-class ships were powered by two 800 horsepower (600 kW) twin turbo-charged Mercedes-Benz diesel engines when waterborne, using water jets (designed by Aerojet),[5] giving them a speed of 12 knots (22 km/h; 14 mph). When foilborne, the ships were powered by a General Electric LM2500 gas turbine and a very large water jet, giving them a speed of over 48 knots (89 km/h; 55 mph).
Thanks for the further information.
The Canela 8 has the forward foils retractable above the water line. The retractable "garage" is also where the step in the hull is which helps get the boat on plane. Also there is a very sophisticated computer on the Canela 8 with multiple sensors to make hundreds of adjustments of foil angle and Dept a minute.
'
ssobol":1nt5buja said:I guess those people will have plenty of money for foil repairs after hitting debris in the water at speed.
Indeed.
It's always interesting when folks posit military gear for civilian use and ignore the battalion of mechanics, supply, and other technicians required to keep those machines operational.
thataway":8hj22bnj said:Foils in the past have had a problem with foils and surface debris. I can remember seeing a Navy foiling ship in the Long Beach Area over 40 years ago. I believe it was run by gas turbines, I also heard that the design was not developed because of the issue hitting debris. I did ride in a foil boat in Sydney Australia in the 80's, so foil boats have been around for a long time. First hydrofoil was in 1906.
The Pegasus-class ships were powered by two 800 horsepower (600 kW) twin turbo-charged Mercedes-Benz diesel engines when waterborne, using water jets (designed by Aerojet),[5] giving them a speed of 12 knots (22 km/h; 14 mph). When foilborne, the ships were powered by a General Electric LM2500 gas turbine and a very large water jet, giving them a speed of over 48 knots (89 km/h; 55 mph).
Thanks for the further information.
....
When I was much younger, they tried running hydrofoil ferries from Seattle to Victoria, BC. When they worked they were pretty fast way to get from one place to the other. However, they had lots of problems with the foils including hitting stuff in the water at speed. The hydro-foil ferries only lasted a season. It was about 1985.
thataway":1ramhw43 said:Foils in the past have had a problem with foils and surface debris. I can remember seeing a Navy foiling ship in the Long Beach Area over 40 years ago. I believe it was run by gas turbines, I also heard that the design was not developed because of the issue hitting debris. I did ride in a foil boat in Sydney Australia in the 80's, so foil boats have been around for a long time. First hydrofoil was in 1906.
The Pegasus-class ships were powered by two 800 horsepower (600 kW) twin turbo-charged Mercedes-Benz diesel engines when waterborne, using water jets (designed by Aerojet),[5] giving them a speed of 12 knots (22 km/h; 14 mph). When foilborne, the ships were powered by a General Electric LM2500 gas turbine and a very large water jet, giving them a speed of over 48 knots (89 km/h; 55 mph).
Thanks for the further information.
....
When I was much younger, they tried running hydrofoil ferries from Seattle to Victoria, BC. When they worked they were pretty fast way to get from one place to the other. However, they had lots of problems with the foils including hitting stuff in the water at speed. The hydro-foil ferries only lasted a season. It was about 1985.
Karl Konecny
Member
I the mid 80's I would take a hydrofoil ferry from Hong Kong to Macao. I believe Boeing made them. I don't know the fate of the boats but so many people went to Macao to gamble that Macao immigration insisted you had a round trip ticket to board the boat so you didn't end up penniless and stranded in Macao.
Wood Zeppelin
New member
Why elec motors are superior
(1) Elec motors have peak torque at 0 rpm (when it is most useful/needed).
(2) 1/3 as many moving parts.
(1) Elec motors have peak torque at 0 rpm (when it is most useful/needed).
(2) 1/3 as many moving parts.