Inboard engines and a changing world

[newhaul]

Originally Posted by newhaul

4000 rpm so a 3.5:1 ratio is about right ( didn't do exact math ) the diesel is 2,000rpm and a 1.8:1 fwd and 2:1 Rev. On the hurth.
Not free but an old comuta car for $200 just needs batteries.

Well got the car and serios score the batteries took a charge so I have 8 gc2 batteries for a full 48v bank . still deciding if I should strip it for the boat or drive it as a car.

[newhaul]

Ok here is a serious question which will determine my convert or not.
My diesel I will install turns at 3600rpm top power of 11hp
My electric motor turns 4000rpm at max 6.5hp.
Now can I use the same 2.1:1 transmission on the electric that is on the diesel?
If yes then all I need to buy is the controller, And throttle lever .

[Pete7]

Think you might want to look at prop speeds because if they turn too quickly they are likely to cavitate. Ours is geared to 1350 revolutions at maximum engine speed.

Pete

[newhaul]

Originally Posted by Pete7

Think you might want to look at prop speeds because if they turn too quickly they are likely to cavitate. Ours is geared to 1350 revolutions at maximum engine speed.

Pete

The hurth 50 is the tyranny that was coupled to the spare westerbeke 10-two I got for parts. Top rpm power curve is 3600 and top on the electric is 4000 just hoping I don't need to spend another grand on reduction gears that would be a deal breaker .

[GordMay]

0.476 [2.1:1 rstio] x 4000 motor RPM = 1905 shaft RPM
0.476 x 3600 engine RPM = 1714 shaft RPM

Sailboat propeller shaft speeds are typically between 850 ➛ 1650 shaft RPM.
Propeller selection [diameter & pitch] can partially mitigate incorrect gear ratios.
Engine RPM, shaft speed and propeller diameter ➥ https://ab-marine.com/knowledge-base...ller-diameter/

“The Propeller Handbook: The Complete Reference for Choosing, Installing, and Understanding Boat Propellers” ~ by Dave Gerr
is available for free online reading at:
➥ http://kashti.ir/files/ENBOOKS/Propeller%20Handbook.pdf

[newhaul]

Originally Posted by GordMay

0.476 [2.1:1 rstio] x 4000 motor RPM = 1905 shaft RPM
0.476 x 3600 engine RPM = 1714 shaft RPM

Sailboat propeller shaft speeds are typically between 850 ➛ 1650 shaft RPM.
Propeller selection [diameter & pitch] can partially mitigate incorrect gear ratios.
Engine RPM, shaft speed and propeller diameter ➥ https://ab-marine.com/knowledge-base...ller-diameter/

“The Propeller Handbook: The Complete Reference for Choosing, Installing, and Understanding Boat Propellers” ~ by Dave Gerr
is available for free online reading at:
➥ http://kashti.ir/files/ENBOOKS/Propeller%20Handbook.pdf

Thank you for this information .
The rpms are variable but the posted are at max hp output. Max torque is a bit lower .
Looking at the numbers it seems the Trans will work so now for a speed controller for 48v and top of 125 amps . That doesn't require a bank loan .

[lifeofreilly57]

Originally Posted by Chotu

As the march to switch to all electric motors for automobiles and trucks continues to accelerate, what will become of our boats?

Will diesel get cheap because the demand drops or will it become a high priced specialty fuel because no one makes it anymore?

What about propane cooktops? Gasoline for outboards? Heaters (diesel, propane, etc)?

People are moving away from these things and it's not slowing down. A lot of people are selling gas stations because they see the writing on the wall.

What do you think will happen to our boats, which mostly run on fossil fuels when not sailing?

Electric vehicles are the future, but not right away.
There still needs to be a lot of support infrastucture built to support it, currently EV sales have dropped dramatically.
Internal combustion engines have been in development for over 100 years, the EV market is still in its infancy. Until huge leaps in battery technology improve the capacity while decreasing the size and weights of the battery bank needed to power a boat for any length of time I don't see it being an alternative, yet. Those who have switched are quite limited in range.
Fossil fuels will be around for quite some time as the transition takes place. Even then, I don't see a sudden drop in diesel fuel production. It'll be a couple decades before it makes that transition.
I do see electric power as the future, but it will trickle down the ladder of application to boats eventually, just not in the foreseeable future. Diesel will still be the primary fuel for heavy trucks, construction equipment and boats. Also, home heting oil is basically diesel fuel with another dye to determin taxability.

[GordMay]

This is all too complicated for me to evaluate, and explain, and I can’t read all the nameplate data, nor locate a data sheet, on your motor.

However, it appears [from the nameplate] that your GE DC Motor #580 49 JB 327 C has an “Intermittent Rated” duty cycle, with Class ‘F’ [155°C/105°C Rise] insulation.

Intermittent Duty [‘S2' or ‘S3', followed by the percentage of time under load] means the loads for which the motor is loaded for short[er] time, and then it is shut down, either for a long duration, or a very short duration. As a general rule, the higher the load, the shorter the run-time, before cooling.

Continuous Duty [‘S1'] means the loads for which the motor operates continuously, for a long time, under the same conditions, without any significant changes in the load. In a continuous duty cycle, the temperature of the motor will continue to increase, until it reaches a steady-state value. If the motor is not properly sized for the load, it may operate at a temperature that exceeds its maximum temperature rating, which can lead to motor failure.

Electric Motor Duty Ratings ➥ https://www.alltorquetransmissions.c...-duty-ratings/

NEMA insulation classes for motors ➥ NEMA insulation classes for motors - Drives and Automation