|
Hello friends,
i just stumbled upon this site and looks like a wealth of information.
I built a little crab skiff during Covid, 21’ narrow and pretty light. Power is currently an Atomic 4 gas engine. ?It is a tunnel drive and turning a 12”- 3 blade cupped “indigo” prop, specifically designed for A4’s. I believe the prop was meant to allow the A4 to turn up and run at 1400 rpm.
the boat currently runs about 14knts wot but is used mostly at 2 to 7 knots which guessing is 500- 1000 rpm.
I can only go an inch bigger prop due to tunnel.
I guess my question is where does one start picking the components?
Can I expect any efficiency with existing prop?
thank you for any feedback
tom
|
Thunderstruck EV is where my kit came from there is a lot of information on the site.
toggle quoted message
Show quoted text
On Dec 27, 2022, at 9:39 AM, Tom@... wrote:
?Hello friends, i just stumbled upon this site and looks like a wealth of information. I built a little crab skiff during Covid, 21’ narrow and pretty light. Power is currently an Atomic 4 gas engine. ?It is a tunnel drive and turning a 12”- 3 blade cupped “indigo” prop, specifically designed for A4’s. I believe the prop was meant to allow the A4 to turn up and run at 1400 rpm. the boat currently runs about 14knts wot but is used mostly at 2 to 7 knots which guessing is 500- 1000 rpm. I can only go an inch bigger prop due to tunnel. I guess my question is where does one start picking the components? Can I expect any efficiency with existing prop? thank you for any feedback tom <2EACD22E-788D-44D1-AB1B-1D32B6CF87D1.jpeg> <A1E5DB80-AE76-457C-AE58-48E58F40EC01.jpeg> <162A3583-DB8C-405E-910B-E9814647F6A6.jpeg>
|
Nicely done! If it were me I would be happy with the current speeds that you are getting, but my boat is electric and the only way it will go that fast is on the trailer. Have fun with your boat. Best Regards Al Hartley
On Tue, Dec 27, 2022 at 10:15 AM Michael Schiller via <captainmike454= [email protected]> wrote: Thunderstruck EV is where my kit came from there is a lot of information on the site. On Dec 27, 2022, at 9:39 AM, Tom@... wrote:
?Hello friends, i just stumbled upon this site and looks like a wealth of information. I built a little crab skiff during Covid, 21’ narrow and pretty light. Power is currently an Atomic 4 gas engine.? It is a tunnel drive and turning a 12”- 3 blade cupped “indigo” prop, specifically designed for A4’s. I believe the prop was meant to allow the A4 to turn up and run at 1400 rpm. the boat currently runs about 14knts wot but is used mostly at 2 to 7 knots which guessing is 500- 1000 rpm. I can only go an inch bigger prop due to tunnel. I guess my question is where does one start picking the components? Can I expect any efficiency with existing prop? thank you for any feedback tom <2EACD22E-788D-44D1-AB1B-1D32B6CF87D1.jpeg> <A1E5DB80-AE76-457C-AE58-48E58F40EC01.jpeg> <162A3583-DB8C-405E-910B-E9814647F6A6.jpeg>
|
i got my kit from Thunderstruck as well. Two thumbs up!
I just changed sprockets/ratios on the gear reduction until my existing prop worked. Much cheaper and easier than changing a prop.?
|
But wouldn't that be far less efficient and a little more noise?
Nick
Sent from my Bell Samsung device over Canada's largest network.
toggle quoted message
Show quoted text
-------- Original message -------- From: kurtphone@... Date: 2022-12-28 10:35 a.m. (GMT-05:00) Subject: Re: [electricboats] Newbie looking for guidance
i got my kit from Thunderstruck as well. Two thumbs up! I just changed sprockets/ratios on the gear reduction until my existing prop worked. Much cheaper and easier than changing a prop.?
|
I was thinking the same thing as Al. If that Atomic 4 is running good why convert?? A4s are super quiet and efficient ICEs. With the exception of using gasoline as its fuel, A4s are awesome and they would definitely be the best way to go 20 kts. But if you have an aversion to gas on a boat , don't want to listen to and smell diesel and don't care of you ever go 20 knots again then that boat looks like it would be an excellent electric boat.?
I'd guess with a solar canopy it could cruise 5 kts just off solar on a sunny day.
If you're sure? electric is the best for you, Thunderstruck is a good place to look for an all inclusive kit for a good price but if you really have a tight budget I'd look at golf cart conversion? kits. I've been running one for 10 years. To say it's a little underpowered is an understatement but it will push the Arc 4 mph on nothing but sunshine and make 5 kits if I suck on the batteries hard. It won't take much to get that boat up to 6 or 7 mph if that's all you want and if you do want to go much faster it won't do it for long unless you spend a fortune on batteries and a lot more on a motor and controller that you won't use most of the time.
Gas or electric though, it's a cool boat.
Capt. Carter Www.shipofimagination.com
On Wed, Dec 28, 2022 at 11:16 AM, 63urban <63urban@...> wrote: But wouldn't that be far less efficient and a little more noise?
Nick
Sent from my Bell Samsung device over Canada's largest network.
-------- Original message -------- From: kurtphone@... Date: 2022-12-28 10:35 a.m. (GMT-05:00) Subject: Re: [electricboats] Newbie looking for guidance
i got my kit from Thunderstruck as well. Two thumbs up! I just changed sprockets/ratios on the gear reduction until my existing prop worked. Much cheaper and easier than changing a prop.?
|
Assuming this was a 18hp Atomic??
You could definitely gain by going with a larger prop. Since you cant go much bigger and you wont need much power at all to push this 6 knots its probably not worth it.?
Personally I think a 3kw motor would be plenty for this boat to putt around.? Since there isn't really any penalty in oversizing, I might go with a 10kw. This would match or exceed the performance of the Atomic.?
I would also try and go direct drive. It may overheat at top speed, but you wont have the battery capacity to keep it there long enough to be an issue.?
I typically don't recommend anything other than LFP for boats. I wouldn't be apposed to it here as long as its in a portable, waterproof enclosure. This will help keep the weight down and in turn have a larger capacity capable of pushing 10kw motor.?
Matt Foley? Sunlight Conversions Perpetual Energy, LLC 201-914-0466
On Wednesday, December 28, 2022 at 12:49:33 PM EST, twowheelinguy via groups.io <twowheelinguy@...> wrote:
I was thinking the same thing as Al. If that Atomic 4 is running good why convert?? A4s are super quiet and efficient ICEs. With the exception of using gasoline as its fuel, A4s are awesome and they would definitely be the best way to go 20 kts. But if you have an aversion to gas on a boat , don't want to listen to and smell diesel and don't care of you ever go 20 knots again then that boat looks like it would be an excellent electric boat.?
I'd guess with a solar canopy it could cruise 5 kts just off solar on a sunny day.
If you're sure? electric is the best for you, Thunderstruck is a good place to look for an all inclusive kit for a good price but if you really have a tight budget I'd look at golf cart conversion? kits. I've been running one for 10 years. To say it's a little underpowered is an understatement but it will push the Arc 4 mph on nothing but sunshine and make 5 kits if I suck on the batteries hard. It won't take much to get that boat up to 6 or 7 mph if that's all you want and if you do want to go much faster it won't do it for long unless you spend a fortune on batteries and a lot more on a motor and controller that you won't use most of the time.
Gas or electric though, it's a cool boat.
Capt. Carter Www.shipofimagination.com
On Wed, Dec 28, 2022 at 11:16 AM, 63urban <63urban@...> wrote: But wouldn't that be far less efficient and a little more noise?
Nick
Sent from my Bell Samsung device over Canada's largest network.
-------- Original message -------- From: kurtphone@... Date: 2022-12-28 10:35 a.m. (GMT-05:00) Subject: Re: [electricboats] Newbie looking for guidance
i got my kit from Thunderstruck as well. Two thumbs up! I just changed sprockets/ratios on the gear reduction until my existing prop worked. Much cheaper and easier than changing a prop.?
|
I have to disagree with ONE thing Matt said. The one penalty for oversizing may only be economic but it is real and could be significant between 3 and 10 HP.
If cost is a minor consideration I'd say a nominal 5-6 kW system would be the sweet spot for most needs and bang/$$$. If your budget is tight, something in the 3 HP range should still push her with authority but might be lacking a little in heavy weather and strong currents. IMO
Capt. Carter Www.shipofimagination.com
On Thu, Dec 29, 2022 at 9:54 AM, Matt Foley <matt@...> wrote: Assuming this was a 18hp Atomic??
You could definitely gain by going with a larger prop. Since you cant go much bigger and you wont need much power at all to push this 6 knots its probably not worth it.?
Personally I think a 3kw motor would be plenty for this boat to putt around.? Since there isn't really any penalty in oversizing, I might go with a 10kw. This would match or exceed the performance of the Atomic.?
I would also try and go direct drive. It may overheat at top speed, but you wont have the battery capacity to keep it there long enough to be an issue.?
I typically don't recommend anything other than LFP for boats. I wouldn't be apposed to it here as long as its in a portable, waterproof enclosure. This will help keep the weight down and in turn have a larger capacity capable of pushing 10kw motor.?
Matt Foley? Sunlight Conversions Perpetual Energy, LLC 201-914-0466
On Wednesday, December 28, 2022 at 12:49:33 PM EST, twowheelinguy via groups.io <twowheelinguy@...> wrote:
I was thinking the same thing as Al. If that Atomic 4 is running good why convert?? A4s are super quiet and efficient ICEs. With the exception of using gasoline as its fuel, A4s are awesome and they would definitely be the best way to go 20 kts. But if you have an aversion to gas on a boat , don't want to listen to and smell diesel and don't care of you ever go 20 knots again then that boat looks like it would be an excellent electric boat.?
I'd guess with a solar canopy it could cruise 5 kts just off solar on a sunny day.
If you're sure? electric is the best for you, Thunderstruck is a good place to look for an all inclusive kit for a good price but if you really have a tight budget I'd look at golf cart conversion? kits. I've been running one for 10 years. To say it's a little underpowered is an understatement but it will push the Arc 4 mph on nothing but sunshine and make 5 kits if I suck on the batteries hard. It won't take much to get that boat up to 6 or 7 mph if that's all you want and if you do want to go much faster it won't do it for long unless you spend a fortune on batteries and a lot more on a motor and controller that you won't use most of the time.
Gas or electric though, it's a cool boat.
Capt. Carter Www.shipofimagination.com On Wed, Dec 28, 2022 at 11:16 AM, 63urban <63urban@...> wrote: But wouldn't that be far less efficient and a little more noise?
Nick
Sent from my Bell Samsung device over Canada's largest network.
-------- Original message -------- From: kurtphone@... Date: 2022-12-28 10:35 a.m. (GMT-05:00) Subject: Re: [electricboats] Newbie looking for guidance
i got my kit from Thunderstruck as well. Two thumbs up! I just changed sprockets/ratios on the gear reduction until my existing prop worked. Much cheaper and easier than changing a prop.?
|
Thank You All,
It is the 30hp A4 currently installed
I know converting from a good running A4 to electric isn't exactly logical but what in boating is?? I do want to try going electric, it suites the way we use her.
If I do it I will use the existing running gear, as easy as it to acess the A4, I may want to put it back in at times.
The hull is very efficent up to 4-6kts (it gets there at idle now)?
Currently if I want to run a trot line I need to drag two 5 gal buckets to go slow enough...The electric will allow for that slow troll.
Tom
|
What kind of boat do you have, Tom ? Here we have all kinds of boats...
What is an "A4" engine (please describe), and what kind of connection do you have between the engine and the prop ?
If you strip the fossile engine, it will be hell to put it back. Good thing is - you will never want to go back !
Carsten
On Thursday, 29 December 2022 at 23:09:42 CET, Tom@... <tom@...> wrote:
Thank You All, It is the 30hp A4 currently installed I know converting from a good running A4 to electric isn't exactly logical but what in boating is?? I do want to try going electric, it suites the way we use her. If I do it I will use the existing running gear, as easy as it to acess the A4, I may want to put it back in at times. The hull is very efficent up to 4-6kts (it gets there at idle now)? Currently if I want to run a trot line I need to drag two 5 gal buckets to go slow enough...The electric will allow for that slow troll. ![]() Tom
|
Hi Tom,
Your boat looks great!
If you're considering something low power on the order of 3 HP and have more time than money, you might get a motor and controller for $100-$200.? Study the torque charts and your propeller geometry to see if you need to modify the prop for higher RPM.? Get a set of 12V (nominal) LiFePO4 batteries for another $100.? You may have an iteration or three to resolve the differences between theory and water.? Once you have it working, buy additional batteries according to how long you want it to run before you switch to oars.
Cheers
Halden
|
The prop has an optimum speed and the motor has an optimum speed. Proper ratio in the gear reduction is when they match. My initial installation at 2.5 to 1 was over propped and I could “overload” the motor. At 3 to 1 it drives the boat much like the old 30hp Volvo only more controllable.?
I noticed no significant change in the noise
level with my ratio changes.?
Thunderstruck advises to not use direct drive without some sort of thrust bearing to save the electric motor bearings from the thrust loads.?
|
That is a good advise, in general ! Always put a thrust bearing in the drive line. Anywhere, between the prop and the main shaft of the motor/engine.
Carsten
On Thursday, 29 December 2022 at 23:44:33 CET, kurtphone@... <kurtphone@...> wrote:
The prop has an optimum speed and the motor has an optimum speed. Proper ratio in the gear reduction is when they match. My initial installation at 2.5 to 1 was over propped and I could “overload” the motor. At 3 to 1 it drives the boat much like the old 30hp Volvo only more controllable.?
I noticed no significant change in the noise
level with my ratio changes.?
Thunderstruck advises to not use direct drive without some sort of thrust bearing to save the electric motor bearings from the thrust loads.?
|
I concur with many here - go to thunderstruck-ev.com for complete kits. Their reduction/motor mount combo makes installation straight forward.?
if you have data - engine RPM - prop RPM - at the speeds you are looking for - this will help in choosing a reduction ratio.?
Once you choose operations time, then you can calculate batter size. I’m an advocate if building your battery from LiFePO4 cells with a suitable BMS ?I did read about a US company selling complete batteries Trophy Battery that seem like quality products.
?
|
Reuben Trane