RE: Jaguar Electric Powerboat: Time For Tea
Friday 15th June 2018
Just in case there was any doubt, Jaguar is extremely serious about its electric ambitions; not only was it a relatively early adopter of Formula E, the I-Pace looks set to take the lessons learnt there into the mainstream.
Jaguar Electric Powerboat: Time For Tea?
And they say water and electricity don't mix...
Now Jaguar is taking its EV knowledge to the water. With a little help from Williams, Jaguar Vector Racing has set its sights on an electric powerboat world record. And, well, they wouldn't have made a video about an unsuccessful record attempt, so here we get to see the record run on video. We'll keep the speed a secret for now though; wouldn't want to spoil the surprise...
The record run took place at Coniston Water, an iconic location in the history of British boat speed runs. While we may be some way off matching Donald Campbell's incredible feats of nautical velocity, how far off can it realistically be? Answers on a postcard please...
Discussion
Good result for electric only.
However the overwrought drama/sense of danger was a load of old b
ks. I could go out now and get in any number of commercially available fossil fueled speed boats and obliterate the speed they achieved here, and be back at the dock in time to pick up the deck fluff and cocktails.
However the overwrought drama/sense of danger was a load of old b
ks. I could go out now and get in any number of commercially available fossil fueled speed boats and obliterate the speed they achieved here, and be back at the dock in time to pick up the deck fluff and cocktails.Buggyjam said:
I’m suprised it’s so slow.
Me too.To put it in perspective, I was involved with the running of an inboard-engined hydroplane that was running faster than this (circa 110mph) back in the 1980's... using a tuned Hillman Imp engine.
If Jaguar splurged media hype around the fact that their latest electric car was faster than a tuned Hillman Imp, would you be impressed?
No, me neither.
Equus said:
Me too.
To put it in perspective, I was involved with the running of an inboard-engined hydroplane that was running faster than this (circa 110mph) back in the 1980's... using a tuned Hillman Imp engine.
If Jaguar splurged media hype around the fact that their latest electric car was faster than a tuned Hillman Imp, would you be impressed?
No, me neither.
This will sound very dubious sciencifitcally but it’s honest To put it in perspective, I was involved with the running of an inboard-engined hydroplane that was running faster than this (circa 110mph) back in the 1980's... using a tuned Hillman Imp engine.
If Jaguar splurged media hype around the fact that their latest electric car was faster than a tuned Hillman Imp, would you be impressed?
No, me neither.
.My first thought was that from what I can tell radio controlled electric boats with brushless motors are a lot faster than their IC counterparts
Granted that’s due to mini engines etc, but I thought surely this can’t be it? I’d not have made such a sing and dance if I were Jag
Buggyjam said:
Anyone with speed boat and/ or electric propulsion knowledge explain why it is so pedestrian?
I have absolutely no knowledge of the subject so this is a total guess, but...I reckon it's down to power and torque and the difference between how an electric car goes fast versus how a boat does it.Electric motors are very good at providing torque which is why electric cars can be made to go so quick. Boats don't require torque as such but just need to spin the prop as quickly as possible.
Someone feel free to explain it properly...
Centurion07 said:
I have absolutely no knowledge of the subject so this is a total guess, but...I reckon it's down to power and torque and the difference between how an electric car goes fast versus how a boat does it.
I think you're on the right lines. If we assume similar mechanical losses in an electric boat drivetrain to an electric car drive train (I know...!) then what's different is what they're running on.The drag of the hull in / on the water, and the amount of power needed to over come that, compared to a car running through air/on a road is going to be huge. Those really fast IC hydroplanes are all running on a cushion of air, with only their props in the water. An electric boat has to do the same to be as quick, but presumably its heavier (all those dratted batteries) and maybe the electric motors aren't so efficient at very high speeds either?
But ultimately it was a ten-year old record, and they only beat it by a handful of knots, despite battery technology supposedly having moved on significantly in that time. It may have been technically difficult, but it just didn't sound all that impressive.
Smokin Donut said:
Wikipedia states:
A modern Unlimited Hydroplane is the world's fastest racing boat, capable of speeds in excess of 200 mph.
Yes I know this wasn't an 'unlimited hydroplane' but anything less than 200mph would be pants.
The propeller driven water speed record stands at 205mph (yes, by an Unlimited Hydroplane - driven by a 3,000 SHP gas turbine aircraft engine), so 200+ with an electric motor just ain't gonna happen.A modern Unlimited Hydroplane is the world's fastest racing boat, capable of speeds in excess of 200 mph.
Yes I know this wasn't an 'unlimited hydroplane' but anything less than 200mph would be pants.
The previous record of 200mph had stood since 1962. It's not an easy record to break.
They certainly need to be looking for 120mph+, though, before they'll impress anyone in the powerboating world.
I suspect it's slow because it's heavy! I've no idea the mass of batteries in this thing, but they have got to weigh more than the normal fuel tank.
A typical high speed powerboat has a low mass and so it "Planes" easily, ie with a low hull drag. A heavy boat can of course still plane, or even "fly" (most racing power boats only have the prop and the rudder and a turn fin actually in the water) but the drag will be higher because the lift force required is higher.
A typical high speed powerboat has a low mass and so it "Planes" easily, ie with a low hull drag. A heavy boat can of course still plane, or even "fly" (most racing power boats only have the prop and the rudder and a turn fin actually in the water) but the drag will be higher because the lift force required is higher.
Centurion07 said:
Buggyjam said:
Anyone with speed boat and/ or electric propulsion knowledge explain why it is so pedestrian?
I have absolutely no knowledge of the subject so this is a total guess, but...I reckon it's down to power and torque and the difference between how an electric car goes fast versus how a boat does it.Electric motors are very good at providing torque which is why electric cars can be made to go so quick. Boats don't require torque as such but just need to spin the prop as quickly as possible.
Someone feel free to explain it properly...
dvs_dave said:
More about power to weight. Boats need a heck of a lot of sustained high power output to overcome the friction of the water. A hydro like this then relies on a cushion of air under it to further reduce friction once it’s going sufficiently quickly. However the batteries required to deliver sufficient sustained power output are very heavy. This of course means the boat needs more power to get up to speed, and a higher speed required for it to get enough aero lift due to its higher weight. It’ll be very much a compromise between maximum sustained battery power output and their consequent weight.
All true and obvious.But as Max says, at high speed, hydroplanes frequently run with only the rudder and half of a surface-piercing propeller (not even their turn fin, on occasion) in the water. Trimmed properly, they're more WIG machines than boats.
We now have functional electric aircraft, and I'm pretty sure they fly faster than 89mph.
The problem is that Jaguar's commitment to breaking the record seems to go as far as bolting an electric outboard onto the back of an otherwise unmodified, standard Formula circuit racing hull. It's the equivalent of taking a Formula 3 car, fitting it with an electric motor and no other modifications, then using it for a straight-line speed record attempt.
Also probably worth pointing out that there appears to be an anomaly in the electric driven record. This happens; usually due to changes in UIM rules - for example the current record for the modern equivalent of those1-litre Imp-engined hydroplanes that we were running at 110mph back in the 1980's is now 89mph - but sometimes simply because someone claims a class record, but fails to claim the outright record (sounds dumb, I know, but you need to fill in the right paperwork to the UIM). In this case, the class speed record for 144V electric hydroplanes already stands 10mph higher than the 'outright' electric record that Jaguar appear to be claiming.
Edited by Equus on Sunday 17th June 08:24
wait? the 'lecy boat runs on just 144 Volts ?? Really? no wonder it's slow!
Electrical power is Volts x amps, so pull say 100A at 144V and you're pulling 14.4kW which is just ~19 bhp. So 190bhp would take 1000 Amps, and as losses are proportional to the current squared, that's a huge in-efficiency....
Is the class limited to 144v deliberately to slow these 'lecy boats down???
Electrical power is Volts x amps, so pull say 100A at 144V and you're pulling 14.4kW which is just ~19 bhp. So 190bhp would take 1000 Amps, and as losses are proportional to the current squared, that's a huge in-efficiency....
Is the class limited to 144v deliberately to slow these 'lecy boats down???
Max_Torque said:
Is the class limited to 144v deliberately to slow these 'lecy boats down???
No.There are classes for 72V and 144V, just as there are classes for various piston engine sizes, gas turbines, and so on (and the gas turbine engined 'Unlimited' circuit racing hydroplanes aren't really unlimited any more; there is actually quite a complicated rule book and their engines are restricted to about 3,000 SHP... you wouldn't have such a restriction with a purpose-built unlimited immersed propeller record-breaker).
It so happens that a boat in the 144V class is also apparently the fastest electric boat in the world, at present - faster than the Jaguar boat.
The Jaguar boat, if it is aiming for the outright Electric record could have run whatever voltage it likes.
I don't know what voltage they using, but the video says that they're using Formula E batteries (I have no interest in Formula E, but Google suggests they run at up to 800V?), and it's the first application of this HV technology to boats.
ETA: The fact that someone with the 144V restriction has already gone faster than Jaguar has managed with much higher voltage makes their achievement even more lacklustre, of course.
Edited by Equus on Sunday 17th June 11:10
A standard FE powertrain in race settings runs a peak of around 230kW, but for a short duration record run and running in a very nice cold cooling medium (unlike the race cars) i'd think that an inverter change (to get more current) would see over 300kW fairly easily. How that compares the existing e-boats i don't know in terms of power output?
Max_Torque said:
... for a short duration record run and running in a very nice cold cooling medium (unlike the race cars) i'd think that an inverter change (to get more current) would see over 300kW fairly easily. How that compares the existing e-boats i don't know in terms of power output?
You're not immersed in the nice, cold cooling medium when you're running fast, of course - and for reasons of hydrodynamic drag, the cooling pickups on racing hydroplanes are as small as you can make them. This is the rudder and water pick-up on Jim Noone's British Unlimited Prop-driven Record Holder (~155mph in a 7-litre Chevy V8-engined hydroplane):
The 'short duration' record run involves accelerating to maximum speed and then maintaining it over a measured kilometre (twice - in opposite directions), so in fact involves running at peak power, full throttle for several minutes, which I suspect is something that a Formula E car never does.
300kW (~400bhp) would see you good for 140+mph in a well designed petrol-engined hydroplane, but but that's not allowing for the extra hydrodynamic and/or aerodynamic drag penalty from weight of batteries.
As I said earlier 120mph+ would be the threshold at which I'd have been willing to say 'good result'. Over 135mph and I'd have been properly impressed.
Edited by Equus on Sunday 17th June 11:47
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