Cigarette AMG Electric Drive
03-26-2026 | 08:22 AM
#13
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Joined: Jan 2006
Posts: 3,598
Likes: 1,168
From: taxachusetts
Hi there,
I still have my 38 foot boat with two GM 502 here in Germany. After starting rebuilding the boat last year I found out that the V8’s need to be overhauled as well. For some years I was building and developing electric motor bikes so I was thinking to convert my boat to electric. The thought is to build two electric motors in a waterproof housing and connect the motor direct with a shaft to the surface propeller. The “drives” would then be connected to the stern like Arneson Surface drives. In the drawing there would be a 500R outboard just as size comparison. The boat should have in the end just two electric drives and no more fuel engines.
Here where some simulated numbers what one drive could achieve:
Propshaft 4000 rpm
Propshaft Torque 1000 Nm or 737 ft lbf
Power: 569 hp
Weight one drive app. 100 kg or 220 lb
More over the 800V Li/ion Battery should have a capacity of 300 kWh and it would weight about 1500 kg or 3300 lb.
Just to be clear I grow up with V8s and still be a fan, but after I looked up the prices for two new Mercruisers with drives and app. 550 hp I thought if doing something new.
What do you think?
Markus
I still have my 38 foot boat with two GM 502 here in Germany. After starting rebuilding the boat last year I found out that the V8’s need to be overhauled as well. For some years I was building and developing electric motor bikes so I was thinking to convert my boat to electric. The thought is to build two electric motors in a waterproof housing and connect the motor direct with a shaft to the surface propeller. The “drives” would then be connected to the stern like Arneson Surface drives. In the drawing there would be a 500R outboard just as size comparison. The boat should have in the end just two electric drives and no more fuel engines.
Here where some simulated numbers what one drive could achieve:
Propshaft 4000 rpm
Propshaft Torque 1000 Nm or 737 ft lbf
Power: 569 hp
Weight one drive app. 100 kg or 220 lb
More over the 800V Li/ion Battery should have a capacity of 300 kWh and it would weight about 1500 kg or 3300 lb.
Just to be clear I grow up with V8s and still be a fan, but after I looked up the prices for two new Mercruisers with drives and app. 550 hp I thought if doing something new.
What do you think?
Markus
03-26-2026 | 08:56 AM
#14
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Joined: Jun 2020
Posts: 518
Likes: 187
From: Holland MI
I have replaced many lenco electric trim tab actuators over the years from the electric motor failing. I personally dont think its a good idea to have an electric motor submerged under water. Heat is a huge killer of electric motors, and if you put one in a waterproof box, where does the heat go? Sure the water will cool the box, but how cold is the water?
03-26-2026 | 08:59 AM
#15
Registered
Joined: Apr 2019
Posts: 112
Likes: 55
From: Michigan
Hi there,
I still have my 38 foot boat with two GM 502 here in Germany. After starting rebuilding the boat last year I found out that the V8’s need to be overhauled as well. For some years I was building and developing electric motor bikes so I was thinking to convert my boat to electric. The thought is to build two electric motors in a waterproof housing and connect the motor direct with a shaft to the surface propeller. The “drives” would then be connected to the stern like Arneson Surface drives. In the drawing there would be a 500R outboard just as size comparison. The boat should have in the end just two electric drives and no more fuel engines.
Here where some simulated numbers what one drive could achieve:
Propshaft 4000 rpm
Propshaft Torque 1000 Nm or 737 ft lbf
Power: 569 hp
Weight one drive app. 100 kg or 220 lb
More over the 800V Li/ion Battery should have a capacity of 300 kWh and it would weight about 1500 kg or 3300 lb.
Just to be clear I grow up with V8s and still be a fan, but after I looked up the prices for two new Mercruisers with drives and app. 550 hp I thought if doing something new.
What do you think?
Markus
I still have my 38 foot boat with two GM 502 here in Germany. After starting rebuilding the boat last year I found out that the V8’s need to be overhauled as well. For some years I was building and developing electric motor bikes so I was thinking to convert my boat to electric. The thought is to build two electric motors in a waterproof housing and connect the motor direct with a shaft to the surface propeller. The “drives” would then be connected to the stern like Arneson Surface drives. In the drawing there would be a 500R outboard just as size comparison. The boat should have in the end just two electric drives and no more fuel engines.
Here where some simulated numbers what one drive could achieve:
Propshaft 4000 rpm
Propshaft Torque 1000 Nm or 737 ft lbf
Power: 569 hp
Weight one drive app. 100 kg or 220 lb
More over the 800V Li/ion Battery should have a capacity of 300 kWh and it would weight about 1500 kg or 3300 lb.
Just to be clear I grow up with V8s and still be a fan, but after I looked up the prices for two new Mercruisers with drives and app. 550 hp I thought if doing something new.
What do you think?
Markus
I currently hold the record for the world’s fastest electric boat at 114.20 mph. https://www.princetonelectricspeedboating.com
I’d be happy to take a deep look into the project with you, if you’d like.
-Andrew
03-26-2026 | 11:02 AM
#18
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Joined: Dec 2025
Posts: 26
Likes: 0
From: Germany
Hi Andrew,
thank you for your answer. How many horsepower had the princeton electric speed boat?
The battery will be made by myself I guess, maybe 27200 Sony US VTC 6 cells, as I have written before I have made some electric motor bikes. One motorbike battery had 600 cells inside and had a capacity of 6.5 kWh and a weight of 32 kg so around 44 of these packs should fit in the boat. This bike was able to produce 50 horsepower and you could go at least 1 hour on the track. Bye the way this picture was made 2015 long time before Stark Vark.
thank you for your answer. How many horsepower had the princeton electric speed boat?
The battery will be made by myself I guess, maybe 27200 Sony US VTC 6 cells, as I have written before I have made some electric motor bikes. One motorbike battery had 600 cells inside and had a capacity of 6.5 kWh and a weight of 32 kg so around 44 of these packs should fit in the boat. This bike was able to produce 50 horsepower and you could go at least 1 hour on the track. Bye the way this picture was made 2015 long time before Stark Vark.
03-26-2026 | 11:37 AM
#19
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Joined: Dec 2025
Posts: 26
Likes: 0
From: Germany
Hi Ryan,
the cooling will be done by splashing water at the stern. I would connect a flexible hose between motor and old engine room, big enough to put in the 3 phase cables and make it breath when the motor gets hot and cold. The motor will have an PTC temperatur sensor so the controller can reduce power when it is hot. The shaft sealing will be done with two shaft sealings similar a mercruiser drive shaft. Maybe you know the material what Mercury uses for the shafts?
the cooling will be done by splashing water at the stern. I would connect a flexible hose between motor and old engine room, big enough to put in the 3 phase cables and make it breath when the motor gets hot and cold. The motor will have an PTC temperatur sensor so the controller can reduce power when it is hot. The shaft sealing will be done with two shaft sealings similar a mercruiser drive shaft. Maybe you know the material what Mercury uses for the shafts?
03-26-2026 | 12:05 PM
#20
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Joined: May 2023
Posts: 101
Likes: 86
From: Spokane Wa
If you have money and time to throw at a project like that, go for it. But I think the performance is going to be extremely underwhelming. Its not like a dirtbike on the track when your are constantly varying the throttle between 0-100%. There is no opportunity for regeneration. Those motors will be under mid to high load basically the whole time and its going to absolutely suck that battery dry. Its also not like an electric car where you get on the highway and cruise and the power requirements are minimal, a tesla at 70mph only needs like 30hp to maintain that speed on the flat and straight. Every single MPH on that Cigarette is more constant power. The idea is much better suited to a trawler application where to weight wont matter and the loads are much more reasonable.
Last edited by mutt2jeff; 03-26-2026 at 12:12 PM.
