Switched to Electric

dLj · Jan 28, 2022

jviss said:
That statement by Watt & Sea is nonsense. I am not kidding, I'm an electrical engineer, and I've made a study of energy conversion. Any bit of energy generated by the hydro charger is taking speed off your boat. Otherwise, it would be magic. Where do you think the energy is coming from?

@jviss - dude - with all due respect - get off your high horse! Oh my, you're an electrical engineer and you've made a study of energy conservation. Have you made a study of turbines running off sailboats? Because if you have, please provide the data.

Note that the Watts & Sea unit is articulated, you can pull it out of the water totally. So when racing and speed is of the utmost importance, you can pull it totally out of the water especially under conditions here the drag will have a measurable effect on your speed. You can then drop it down and generate electricity when the sailing conditions are such that it won't have a measurable affect on your hull speed. See @DArcy 's post above...

No one is suggesting that conservation of energy is not being maintained. That's a fundamental law of physics, we all agree. However, this is a very complex system with many variables at play.

dj

jviss · Jan 28, 2022

dLj said:
@jviss - dude - with all due respect - get off your high horse! Oh my, you're an electrical engineer and you've made a study of energy conservation. Have you made a study of turbines running off sailboats? Because if you have, please provide the data.

Note that the Watts & Sea unit is articulated, you can pull it out of the water totally. So when racing and speed is of the utmost importance, you can pull it totally out of the water especially under conditions here the drag will have a measurable effect on your speed. You can then drop it down and generate electricity when the sailing conditions are such that it won't have a measurable affect on your hull speed. See @DArcy 's post above...

No one is suggesting that conservation of energy is not being maintained. That's a fundamental law of physics, we all agree. However, this is a very complex system with many variables at play.

dj

You can't defy the laws of physics. Just look at the energy budget. There's no free lunch.

dLj · Jan 28, 2022

jviss said:
In which case, it's a waste of time and money to try to put a meaningful amount of energy back into a propulsion bank with such a generator, no?

That has not been the opinion of some of the most knowledgeable sailors in the world. In fact, I just used one of the countries foremost authorities on sailboat electrical systems and this specific system was HIGHLY recommended as the best system for generating electricity when sailing for extended voyaging. That means, if you are crossing oceans, or sailing legs where you are sailing for at least seveal days, this is the most highly recommended system available today. Note all the caveats - not for day sailing, yada yada yada...

dj

dLj · Jan 28, 2022

jviss said:
You can't defy the laws of physics. Just look at the energy budget. There's no free lunch.

No one has said there is. Well, except you.

dj

jviss · Jan 28, 2022

dLj said:
That has not been the opinion of some of the most knowledgeable sailors in the world. In fact, I just used one of the countries foremost authorities on sailboat electrical systems and this specific system was HIGHLY recommended as the best system for generating electricity when sailing for extended voyaging. That means, if you are crossing oceans, or sailing legs where you are sailing for at least seveal days, this is the most highly recommended system available today. Note all the caveats - not for day sailing, yada yada yada...

dj

Not for recharging a propulsion bank! Geez. Sure, a parasitic turbine/prop generator for making a bit of charge for radios, etc. But recharging a propulsion bank - not!

Scott T-Bird · Jan 28, 2022

Uma talks about the regen factors and obstacles. When they got their new OceanVolt motor they also changed out the saildrive and prop for the increased regen capability. I believe they discussed that there is a significant compromise between prop efficiency and regen output as was mentioned. They chose to favor regen output and sacrifice prop efficiency, because regen is important to them while the motoring speed is not. On long passages, they regen when the wind is up, the regen is maximized, and sailing speed is not noticeably affected. Besides, they don't mind the time. They are "in no hurry to go anywhere, EVER". It's a choice that not everyone makes. That doesn't mean it is a waste of time and money. They choose the priorities. They do have to conserve energy and have alternate sources ... that's a given.

dLj · Jan 28, 2022

jviss said:
Not for recharging a propulsion bank! Geez. Sure, a parasitic turbine/prop generator for making a bit of charge for radios, etc. But recharging a propulsion bank - not!

It seems to me you are confusing trying to recharge propulsion bank while the propulsion bank is being used. So we are in complete agreement there. In fact, in the case of the integrated system you can't do both at the same time. If one were to put on an external turbine such as the Watts and Sea, then you'd probably want to pull that unit out of the water for less drag when under motor.

But I'd absolutely want the ability to recharge a propulsion bank this way if I was sailing long distances. Note the key term here "sailing".

dj

jviss · Jan 28, 2022

dLj said:
It seems to me you are confusing trying to recharge propulsion bank while the propulsion bank is being used.

No, I'm not.

Scott T-Bird · Jan 28, 2022

jviss said:
Not for recharging a propulsion bank! Geez. Sure, a parasitic turbine/prop generator for making a bit of charge for radios, etc. But recharging a propulsion bank - not!

Well, the wind is the primary propulsion bank. Nobody is suggesting that regen is capable of supporting continuous motoring. When you are reefing to slow down in high wind, regen is providing a windfall of energy at no loss of speed. You choose your times for regen and feather the prop when your batteries are replenished or the wind is light (and conserve energy). It's a dance for sure ... but worthwhile for sailors who have the time and know-how.

dLj · Jan 28, 2022

Phil said:
I've been following the Sailing Uma YouTube channel for a while. They are definitely a great source for real world information. They also have an awesome approach to how they go on their adventures.

Can't agree more! I was one of their patrons for awhile. But I had so many problems with Patreon I finally cut it off. Nothing about Uma, just that interface really was bad. I think they make some of the best sailing videos around. There are others that are also quite good. For sure Uma is excellent. I'd quite enjoy meeting them sometime....

You and your daughter seem to have some really nice sailing adventures. I wish at least one of my daughters would have grabbed the sailing bug but no such luck... Not that I didn't try... Just ask them... LOL

dj

jviss · Jan 28, 2022

Scott T-Bird said:
Well, the wind is the primary propulsion bank. Nobody is suggesting that regen is capable of supporting continuous motoring. When you are reefing to slow down in high wind, regen is providing a windfall of energy at no loss of speed. You choose your times for regen and feather the prop when your batteries are replenished or the wind is light (and conserve energy). It's a dance for sure ... but worthwhile for sailors who have the time and know-how.

All that I was trying to say, is that an electrically propelled yacht without a generator, like the Hinckley 42 daysailer, for example, is a dock-to-dock daysailer or coastal cruiser, and an in-water, prop-driven generator is virtually useless in charging a propulsion bank. You're not going to be sailing enough, at any speed, to make a dent in a propulsion bank. You won't even generate enough to keep a fridge going!

DArcy · Jan 28, 2022

jviss said:
In which case, it's a waste of time and money to try to put a meaningful amount of energy back into a propulsion bank with such a generator, no?

For me, absolutely! But for someone long distance voyaging then no, it really could be worth it. Although I would argue spending $3k on that hydro generator would be a tough sell, having a free generator as part of your electric drive could be worth it.
Let's say you burn 5000W when running the engine and can only generate 100W when sailing - 5000W would move a 30ft boat at a few knots in flat water. That's a 50:1 ratio of sailing to motoring. If you sail 50 times more than you motor it's worth it. That's without solar, wind or shower power.
Let's say Phil wants to sail from California to Hawaii, he's not in a hurry and plans on averaging 3 knots (28 day tip). So if he motors less than 13 hours then it's worth it. More than 13 hours and he will need a BIG solar panel.

dLj · Jan 28, 2022

Phil said:
Yeah...my oldest daughter is quite the sailing geek. She starting sailing at age 6, raced FJs and 420s in college, crewed on a ~35' Jboat for races in college (can't remember the model), just finished her first crossing to Hawaii from Mexico, and is busy coming up with all kinds of adventures for Kolibri. Her boat handling skills are also amazing. I taught her a ton of stuff when she was a kid and she's now teaching me all kinds of new skills.

Oh man! It just doesn't get better than that does it!!!! Enjoy it for as long as you can! Ya gotta just love it when they start teaching you!

Don't' stop sharing your trips! We all very much enjoy seeing/hearing about them.

dj

jon hansen · Jan 28, 2022

sailing is a "dance" we all do love that part!

Richard19068 · Jan 28, 2022

jviss said:
Where do you think the energy is coming from?

Isn't it coming from the wind?

If there is enough wind or more to get up to hull speed it doesn't seem there would be that much loss from the generator in the water.

NB: I am not an engineer.

Scott T-Bird · Jan 28, 2022

jviss said:
All that I was trying to say, is that an electrically propelled yacht without a generator, like the Hinckley 42 daysailer, for example, is a dock-to-dock daysailer or coastal cruiser, and an in-water, prop-driven generator is virtually useless in charging a propulsion bank. You're not going to be sailing enough, at any speed, to make a dent in a propulsion bank. You won't even generate enough to keep a fridge going!

I think you're wrong about that ... what kind of electrical engineer are you?

Davidasailor26 · Jan 28, 2022

jviss said:
These are not LiFePO4, they are LION.

The OP said “12 Battle Born batteries.” Battle Born sells LiFePO4 batteries. Based on https://www.custommarineproducts.com/uploads/1/4/3/7/1437708/qms_lifepo4_manual.pdf (with similar words from other sources): “The round-trip energy efficiency of a LiFePO4 battery is over 90%. … A LiFePO4 battery will still achieve 90% efficiency under shallow discharge conditions.”

Regarding the speed loss from regen - I’ve looked at my own speed comparisons between a freewheeling OEM fixed prop and a replacement Flex-o-fold. At low wind speeds the difference is definitely significant - over half a knot. But as wind speed increases the difference converges to basically nothing as the force to keep moving close to hull speed and the power available from the wind dwarf the excess drag from the prop. Obviously a regen turbine is more drag than a freewheeling prop, but conceptually I could imagine the same dynamic applying to make the speed loss minimal at close to hull speed.

DArcy · Jan 28, 2022

That is

Phil said:
Yeah...my oldest daughter is quite the sailing geek. She starting sailing at age 6, raced FJs and 420s in college, crewed on a ~35' Jboat for races in college (can't remember the model), just finished her first crossing to Hawaii from Mexico, and is busy coming up with all kinds of adventures for Kolibri. Her boat handling skills are also amazing. I taught her a ton of stuff when she was a kid and she's now teaching me all kinds of new skills.

That is fantastic Phil! My older girls are not sailors but my youngest is now on the Canadian Optimist team and is going to the 2022 South American Championship which is an invitational. I won't be surprised if in a couple years she is outsailing me.
Maybe one day I will get to sail across an ocean with her.