CarpeDiem 430 Posted February 28 Share Posted February 28 16 hours ago, Bad Kitty said: I tried really hard to make it work for me, but ended up going 2 x 40hp diesel again, and don't regret it for a minute. The all-electric solution is, imho, not mature enough or well proven enough. There are numerous boats that have gone that way, and then ripped it all out & refitted ICE drivetrains. Ultimately, every now & then you may need to motor for 48 hours, and nothing all electric will do it. Not in small craft size. But you have a generator for when you need it. A purpose spec'd marine generator with a matched alternator is many times more efficient than a diesel sail drive engine. Our engines waste so much energy. I agree you can't get away from having a generator when you also have tight schedules and can't afford to Bob around for 48hrs waiting for favorable winds. Quote Link to post Share on other sites
CarpeDiem 430 Posted February 28 Share Posted February 28 18 hours ago, Saltynuts said: I really can't understand why anyone would fit electric propulsion. The extra expense, range issues and they are worse for the environment than an ice engine. An hydro generating electric motor with appropriate battery storage and a optimally engineered ice engine is an order of magnitude better for the environment. Running an ice engine at optimal torque with all the energy that can be being pumped into the batteries and nothing being wasted is why hybrid cars are so efficient. On a hybrid boat you get the double whammy option of being able to have extended range by having a propellor drive as well that can be also spun by the batteries or the diesel. When you are sailing you are also charging the batteries. And if the batteries go flat you can engage the engine. Quote Link to post Share on other sites
Black Panther 1,587 Posted February 28 Share Posted February 28 1 hour ago, CarpeDiem said: I agree you can't get away from having a generator when you also have tight schedules and can't afford to Bob around for 48hrs waiting for favorable winds. The difference between want vs need. 1 Quote Link to post Share on other sites
waikiore 399 Posted February 28 Share Posted February 28 Though on the average cruising yacht space is at a premium and you are buying an expensive battery bank, an expensive proper marine genset (diesel) an electric motor and all the installation and room requirements that entails . Not entirely sure how a genset running through batteries to power an electric motor is more efficient than a diesel through a gearbox to shaft?. Then of course what happens to the large battery bank when it is had it. I have been involved in some of this stuff, lecky powered gunboats with hydro generation through Gori prop. Repowering existing cruising Cats with diesels and utilising big battery banks and Integrel smart charging on the engines (taking away the need for separate gensets) ..... Quote Link to post Share on other sites
Black Panther 1,587 Posted February 28 Share Posted February 28 For me the main purpose of going electric is to not have an ice engine. I'm happy to go a bit slower and 60 NM is plenty of range. Recharging off grid is an issue, but the technology continues to improve. 1 Quote Link to post Share on other sites
CarpeDiem 430 Posted February 28 Share Posted February 28 18 minutes ago, waikiore said: Then of course what happens to the large battery bank when it is had it. LTO cells have 30000 cycles. LFP cells have conservatively 3000 cycles. Most now have 7000 cycles. Assume you are in a marina, you charge your batteries every week and you motor your full battery capacity (call it a conservative 15Nm) every weekend on a 3000 cycle battery bank... That's 57 years of weekend usage. They are going to outlast the boat. You run the generator occasionally cause you picked a light wind weather window and you are on a tight schedule. After 4.5 years I have put 225hrs on the engine. The most use it gets is making a deadline cause theirs no wind. Which is typically the delivery home from coastal or bay week. I have room for a smaller lighter engine, fuel and 24kwh of batteries. Which apparently would give me 20Nm at 4knots. The numbers stack up for me. Ymmv 1 Quote Link to post Share on other sites
Saltynuts 6 Posted February 28 Share Posted February 28 3 hours ago, CarpeDiem said: An hydro generating electric motor with appropriate battery storage and a optimally engineered ice engine is an order of magnitude better for the environment. Running an ice engine at optimal torque with all the energy that can be being pumped into the batteries and nothing being wasted is why hybrid cars are so efficient. On a hybrid boat you get the double whammy option of being able to have extended range by having a propellor drive as well that can be also spun by the batteries or the diesel. When you are sailing you are also charging the batteries. And if the batteries go flat you can engage the engine. When I repowered a couple of years ago I was quite excited about going electric. I researched it quite extensively but as much as I wanted it to work, I just couldn't make it stack up. The quantity of battery storage and solar panels needed for typical use just doesn't work. Weight, space, expense, range and windage were all major issues. Without getting into the politics of the global warming nonsense, it doesn't stack up environmetally either. https://www.yachtingmonthly.com/news/electric-propulsion-not-most-green-study-finds-95997 1 Quote Link to post Share on other sites
CarpeDiem 430 Posted February 28 Share Posted February 28 42 minutes ago, Saltynuts said: Without getting into the politics of the global warming nonsense, it doesn't stack up environmetally either. https://www.yachtingmonthly.com/news/electric-propulsion-not-most-green-study-finds-95997 That's a great article. Thanks for sharing. I feel like I missed an opportunity to go electric 5 yrs ago... Now reading that maybe I didn't.. Haha Quote Link to post Share on other sites
aardvarkash10 960 Posted February 29 Share Posted February 29 1 hour ago, Saltynuts said: Without getting into the politics of the global warming nonsense that's not politics, its science. 1 2 Quote Link to post Share on other sites
Bad Kitty 252 Posted February 29 Share Posted February 29 6 hours ago, CarpeDiem said: But you have a generator for when you need it. A purpose spec'd marine generator with a matched alternator is many times more efficient than a diesel sail drive engine. Our engines waste so much energy. I agree you can't get away from having a generator when you also have tight schedules and can't afford to Bob around for 48hrs waiting for favorable winds. You can't run the generator to charge the batteries & motor continuously. If you're happy drifting around waiting for batteries to charge while a tropical depression is headed your way then all good, me, I'm not. Quote Link to post Share on other sites
aardvarkash10 960 Posted February 29 Share Posted February 29 Hell, the 2qm20 in SO is now 50 years old. It's done about 70 hours a year for the past 4 years, so probably about 3500 hours in its lifetime. It uses around 3 litres an hour at cruise revs, so close to 10,000 litres in its lifetime. That's about a 10 tonnes of diesel. Which generates about 26 tonnes of CO2 or half a tonne per year. SO was bought because we couldn't fly to Japan for ski trips during COVID. Those flights were about 22 hours return. A passenger generates around 90kg of CO2 emissions per hour when flying. For two people our flight would have generated almost four tonnes of CO2 each year. We are therefore in credit. The diesel stays. 1 Quote Link to post Share on other sites
K4309 257 Posted February 29 Share Posted February 29 3 minutes ago, aardvarkash10 said: Hell, the 2qm20 in SO is now 50 years old. It's done about 70 hours a year for the past 4 years, so probably about 3500 hours in its lifetime. It uses around 3 litres an hour at cruise revs, so close to 10,000 litres in its lifetime. That's about a 10 tonnes of diesel. Which generates about 26 tonnes of CO2 or half a tonne per year. SO was bought because we couldn't fly to Japan for ski trips during COVID. Those flights were about 22 hours return. A passenger generates around 90kg of CO2 emissions per hour when flying. For two people our flight would have generated almost four tonnes of CO2 each year. We are therefore in credit. The diesel stays. Personally, I think worrying about how much diesel a sailing boat burns is a nonsense. Quoting Aa's example as a good example of relativity. I'm constantly reading boat reviews in the magazines about launches, fizz boats what not. The amount of diesel or petrol those things burn is eye-watering. Just reading about the latest fishing boat, innovative design and what not, they recon it is fantastic fuel economy burning 2.65l per nautical mile. It is designed for day trips and has a 550l fuel tank. You can upgrade that to an 800l fuel tank!?!?! If you are going electric drive purely for environmental benefit on a yacht, you need to be very careful the environmental cost of the batteries and associated ancillary's don't outweigh the amount of fuel you'd burn over the life of the boat. Then there is outboards. I've got a little 2hp Yamaha. It's 2 stroke which is not great for the environment. I know people look at electric outboards for various reasons, one of which the impact on the environment. I use my outboard for dinghy fishing missions regularly and am putting a lot of hours on the outboard. But the thing is, 1l of two stroke oil has lasted about 2 years so far. Sure the 2 stroke motor puts oil into the sea, but the actual amount is very very minor. It doesn't take much new consumerism / consumption of new batteries, motors etc to offset any environmental benefits you'd get from ditching the 2 stroke. I know there are other benefits like power autonomy in remote pacific islands, or the stealth factor for fishing (reportedly makes a difference), but in the environmental element, I don't think the benefits are there. 2 Quote Link to post Share on other sites
aardvarkash10 960 Posted February 29 Share Posted February 29 31 minutes ago, K4309 said: , I don't think the benefits are there. Can I just reword that slightly. The environmental benefit of not using any petroleum products are definitely there, but the relative benefit of (insert alternative technology or activity here) vs petroleum fuel use is a far more fraught equation. For example, if I had to row our dinghy everywhere the general public would be exposed to unacceptable levels of vulgarity. Quote Link to post Share on other sites
khayyam 68 Posted February 29 Share Posted February 29 1 hour ago, Bad Kitty said: You can't run the generator to charge the batteries & motor continuously. If you're happy drifting around waiting for batteries to charge while a tropical depression is headed your way then all good, me, I'm not. Surely that just depends on how you spec it. Hybrid cars can. Quote Link to post Share on other sites
CarpeDiem 430 Posted February 29 Share Posted February 29 2 hours ago, Bad Kitty said: You can't run the generator to charge the batteries & motor continuously. That's exactly what you do. The HH44 has a 10kW engine which is just a stock standard 3 cylinder kuboto red mechanical diesel that we all know. It has a 10 kW generator attached to the output shaft and also has the typical shaft drive propellor that most boats have. So the 10kW engine can be delivering 6kW to the drive shaft propelling the boat while driving the generator at 4kW charging your battery bank. When you stop the engine the battery powers the generator spinning the drive shaft. When you put the sails up the propellor spins the generator charging the batteries. This is even more efficient than hybrid cars which convert mechanical to electrical and back to mechanical. And hybrid cars have been charging batteries while you drive since forever. Quote Link to post Share on other sites
Bad Kitty 252 Posted February 29 Share Posted February 29 24 minutes ago, CarpeDiem said: That's exactly what you do. The HH44 has a 10kW engine which is just a stock standard 3 cylinder kuboto red mechanical diesel that we all know. It has a 10 kW generator attached to the output shaft and also has the typical shaft drive propellor that most boats have. So the 10kW engine can be delivering 6kW to the drive shaft propelling the boat while driving the generator at 4kW charging your battery bank. When you stop the engine the battery powers the generator spinning the drive shaft. When you put the sails up the propellor spins the generator charging the batteries. This is even more efficient than hybrid cars which convert mechanical to electrical and back to mechanical. And hybrid cars have been charging batteries while you drive since forever. OK, so that is a true hybrid system. To motor continuously you are running a main engine, whole also charging batteries. So isn't that just a more expensive, heavier ICE drivetrain, with a whole lot more embedded carbon in it's manufacture, & battery disposal implications at some time, for the ability to motor quietly for a short distance? I'm still not seeing the real world planet saving impact? Quote Link to post Share on other sites
CarpeDiem 430 Posted February 29 Share Posted February 29 28 minutes ago, Bad Kitty said: OK, so that is a true hybrid system. To motor continuously you are running a main engine, whole also charging batteries. So isn't that just a more expensive, heavier ICE drivetrain, with a whole lot more embedded carbon in it's manufacture, & battery disposal implications at some time, for the ability to motor quietly for a short distance? I'm still not seeing the real world planet saving impact? Well the boat also has 4kW of solar. So on a good day you could motor for 8 hrs without touching the battery... But yes it's definitely a whole lot more expensive... Reality is you don't need the generator. But everyone wants the generator because of range anxiety. An OceanVolt spec'd plug in non hybrid package (no generator) for Carpe Diem that would weigh less than the engine, take less space than engine and fuel tank, would give me 50Nm of range fully charged from shore power. The only time I have ever motored that far is on a time sensitive trip... otherwise I wait for the wind. So I would need to change my ways. Which I won't be cause I just repowered and if that engine gets 50 years it will outlast me. Quote Link to post Share on other sites
darkside 61 Posted February 29 Share Posted February 29 Sail boat engine revs are constant and hopefully set at the most efficient revs. The gains of hybrid system on a yacht will be less than any machine with variable load and engine revs. The HH has plenty of roof for solar and should sail better than most cats in the light. It might work out OK. I would worry about long term reliability. I see you can get electric sail drives now. For a cat how about one diesel and one electric? Quote Link to post Share on other sites
aardvarkash10 960 Posted February 29 Share Posted February 29 Meh Kick out the ICE diesel and go gas turbine on your genset. A bitch to start, but very efficient at fixed rpm, run on any liquid fuel, and that pleasing jet engine howl to leave them all scratching their heads. And you can cook over the exhaust. 1 Quote Link to post Share on other sites
DrWatson 375 Posted February 29 Share Posted February 29 19 hours ago, K4309 said: Personally, I think worrying about how much diesel a sailing boat burns is a nonsense. Quoting Aa's example as a good example of relativity. I'm constantly reading boat reviews in the magazines about launches, fizz boats what not. The amount of diesel or petrol those things burn is eye-watering. Just reading about the latest fishing boat, innovative design and what not, they recon it is fantastic fuel economy burning 2.65l per nautical mile. It is designed for day trips and has a 550l fuel tank. You can upgrade that to an 800l fuel tank!?!?! If you are going electric drive purely for environmental benefit on a yacht, you need to be very careful the environmental cost of the batteries and associated ancillary's don't outweigh the amount of fuel you'd burn over the life of the boat. Then there is outboards. I've got a little 2hp Yamaha. It's 2 stroke which is not great for the environment. I know people look at electric outboards for various reasons, one of which the impact on the environment. I use my outboard for dinghy fishing missions regularly and am putting a lot of hours on the outboard. But the thing is, 1l of two stroke oil has lasted about 2 years so far. Sure the 2 stroke motor puts oil into the sea, but the actual amount is very very minor. It doesn't take much new consumerism / consumption of new batteries, motors etc to offset any environmental benefits you'd get from ditching the 2 stroke. I know there are other benefits like power autonomy in remote pacific islands, or the stealth factor for fishing (reportedly makes a difference), but in the environmental element, I don't think the benefits are there. Thing I’m most happy about with my electric motor is the removal of the petrol and the stinking outboard from my lazarete I think I will buy the next engine size up when and if this one craps out tho. A bit more oompf would be good. Quote Link to post Share on other sites
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