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Cap Erict3 · 15-11-2016, 08:40

An acquaintance started an EP conversion on a 27' Catalac 2 years ago. He was very excited about the project and was constantly extolling the changes it would bring to his sailing experience.

After completing the installation on the port side, installing a new 48vdc generator, solar panels and battery bank, he became quiet about the upgrade. It seems the sea trial results did not match the vendors claims.

I have not heard that he plans to replace his starboard diesel.

EP boats are anything but new. Duffy has sold a popular electric boat for over 40 years. I used to see one regularly down in Corpus Christi. Cute boat. Never saw it very far from its dock though.

Here is a write up on EP boat history.

https://en.m.wikipedia.org/wiki/Electric_boat

BigBeakie · 15-11-2016, 18:04

Quote:

Originally Posted by StuM

Yep, a round the world race boat has exactly the same use case as a cruising yacht - not!

And another perfect piece of marketspeak:

Christian Hallberg: In fact, we initially developed the system for the 2016 Vendee Globe with another French team, which I can’t mention. That’s how we started working on passing the IMOCA 60 rule tests. The first one was a bollard pull test. The engine needed to create a bollard pull of 280 tons for 15 minutes. We thought this was going to be really tight for us, but we achieved it.
The second one requires the boat to run at a specific speed for 5 hours. That put stress on the batteries, but again the test went well.

Strange that they are very specific about the bollard pull criteria (and we know that EP is great at that because of the low RPM speed torque) but don't tell us what the "specific speed" for 5 hours was. (Can't be very high since they only have 600Ah or so of battery @ 12V).

I also found this amusing
"The whole idea behind Conrad’s ambition is to use the electric motor as a hydrogenerator, too. ...That way, he doesn’t have to put more drag on his boat and he can feed his boat with energy, without requiring fuel. He will carry some fuel, but only for emergencies....He installed the battery in the same compartment as the diesel engine."

So basically, he's stuck an EP motor in there primarily as a hydrogenerator to supply his electical needs and will still have his diesel engine for propulsion.

Hi Stu, glad to hear your're amused

You may not be aware that these Vendee Globe racers have huge power demands, so their power generation and management is critical to them being able to keep racing. Just thought you should know that, and so yes, Coleman uses the OceanVolt every day for regeneration. But he only has one prop in the water and that is connected to...you guessed it, the same OceanVolt SD15 electric motor, in case he needs to motor. So no, he doesn't have a diesel engine for propulsion, it is for a redundant DC generator. He also has Watt & Sea on-board as further redundancy, same as many of the other racers. Oh, and also solar. Imagine that!

And FYI, the OceanVolt SD15 produces 2kW of battery charging at 6.5 knots boat speed and goes up very fast from there. Compare that to Watt & Sea and the robustness/reliability difference, and you'll perhaps see why the other Vendee Globe crews are watching closely.

I fail to see what's amusing about all that, but as long as you're happy. And since robustness and reliability of power generation is not of any real concern to cruisers, so yeah, I guess you're right, this has nothing to interest cruisers as it's not a good "use case".

**Jim Cate** · 15-11-2016, 18:13

Backing up a moment... the requirement for 280 tonnes of bollard pull... can that be correct? I find it hard to imagine that a prop that a racer would be willing to drag could possibly generate that kind of thrust, no matter what sort of engine/motor was attached to it. Or am I missing something here?

Jim

SV DestinyAscen · 15-11-2016, 19:00

Quote:

Originally Posted by BigBeakie

Hi Stu, glad to hear your're amused

You may not be aware that these Vendee Globe racers have huge power demands, so their power generation and management is critical to them being able to keep racing. Just thought you should know that, and so yes, Coleman uses the OceanVolt every day for regeneration. But he only has one prop in the water and that is connected to...you guessed it, the same OceanVolt SD15 electric motor, in case he needs to motor. So no, he doesn't have a diesel engine for propulsion, it is for a redundant DC generator. He also has Watt & Sea on-board as further redundancy, same as many of the other racers. Oh, and also solar. Imagine that!

And FYI, the OceanVolt SD15 produces 2kW of battery charging at 6.5 knots boat speed and goes up very fast from there. Compare that to Watt & Sea and the robustness/reliability difference, and you'll perhaps see why the other Vendee Globe crews are watching closely.

I fail to see what's amusing about all that, but as long as you're happy. And since robustness and reliability of power generation is not of any real concern to cruisers, so yeah, I guess you're right, this has nothing to interest cruisers as it's not a good "use case".

To me there's an underlying tyranny of physics. Cruisers don't average 12 knots. Hydrogenerators are one of those things that work great in the right application, but I can't see how it translate to cruisers whose boats avg 150 miles day especially when the hydrogenerators don't seem to kick in with any meaningful wattage until you're doing six knots.

BigBeakie · 15-11-2016, 19:10

Quote:

Originally Posted by SV DestinyAscen

To me there's an underlying tyranny of physics. Cruisers don't average 12 knots. Hydrogenerators are one of those things that work great in the right application, but I can't see how it translate to cruisers whose boats avg 150 miles day especially when the hydrogenerators don't seem to kick in with any meaningful wattage until you're doing six knots.

2 kW at 6.5 knots is't too shoddy, is it? It's not a straight line graph, it curves up real fast.

SV DestinyAscen · 15-11-2016, 19:18

It does indeed. Just the kickin is too fast for most.

BigBeakie · 15-11-2016, 19:18

Quote:

Originally Posted by Jim Cate

Backing up a moment... the requirement for 280 tonnes of bollard pull... can that be correct? I find it hard to imagine that a prop that a racer would be willing to drag could possibly generate that kind of thrust, no matter what sort of engine/motor was attached to it. Or am I missing something here?

Jim

Jim,

That got my attention too.

I think it's a typo, as in an extra eight and zero. Or a missing decimal point between the 2 and 8 maybe??

And I don't think any of them drag around a fixed blade prop. Coleman reports no drag apparent on his speed instruments, of which I would think he has good calibrated ones. The OceanVolt SD15 has a folder.

The boat has good data logging, so there will be some really interesting information coming.

BigBeakie · 15-11-2016, 19:21

Quote:

Originally Posted by SV DestinyAscen

It does indeed. Just the kickin is too fast for most.

Yep, sure is. That's where the robustness comes in. I'm wondering how he'll go in the southern ocean when he's averaging in the 20's?? That'll be a helluva lot of power!

**Jim Cate** · 15-11-2016, 19:39

Quote:

Originally Posted by BigBeakie

Jim,

That got my attention too.

I think it's a typo, as in an extra eight and zero. Or a missing decimal point between the 2 and 8 maybe??

And I don't think any of them drag around a fixed blade prop. Coleman reports no drag apparent on his speed instruments, of which I would think he has good calibrated ones. The OceanVolt SD15 has a folder.

The boat has good data logging, so there will be some really interesting information coming.

Beakie, how can you get regeneration with a folding prop? When you stop the engine or put it in neutral the prop folds and can't spin the generator.

Something funny here... they must have some means of driving the generator, and also some means of disconnecting it for when there is no need for the electrical generation (if ever!). No racer would accept that drag 24/7.

Jim

SDChristian · 15-11-2016, 19:47

Quote:

Originally Posted by Jim Cate

Beakie, how can you get regeneration with a folding prop? When you stop the engine or put it in neutral the prop folds and can't spin the generator.

Something funny here... they must have some means of driving the generator, and also some means of disconnecting it for when there is no need for the electrical generation (if ever!). No racer would accept that drag 24/7.

Jim

Prop turns 180 and faces backward. Water forces blades opens and starts spinning them.

BigBeakie · 15-11-2016, 19:55

Quote:

Originally Posted by SDChristian

Prop turns 180 and faces backward. Water forces blades opens and starts spinning them.

Good guess but, wrong. Much more elegant than that.

BigBeakie · 15-11-2016, 20:05

Quote:

Originally Posted by Jim Cate

Beakie, how can you get regeneration with a folding prop? When you stop the engine or put it in neutral the prop folds and can't spin the generator.

Something funny here... they must have some means of driving the generator, and also some means of disconnecting it for when there is no need for the electrical generation (if ever!). No racer would accept that drag 24/7.

Jim

That's correct, Jim. They spin the blades open just enough to have the water flowing past speed them up. So they get maximum energy from the water flow without the hassles of locking blades or stress on the prop mechanism.

When you want to stop regen you just put the motor in neutral or turn it off, and the folding prop does it's thing and folds.