IPS v Zeus. Was MBY article fair?

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Did anyone see the gushing best thing since sliced bread article on the new CMD Zues system in this month's MBY? Well I think it was less than fair to Volvo's IPS system. They criticised Volvo for charging extra for some add-ons that are included as standard in the Zues system eg joystick control but completely failed to mention whether the basic price of each system is comparable. So, does anyone know how the basic prices of IPS and Zues compare on a like for like basis?
Then they sort of glossed over the fact that, based on admittedly limited experience, IPS would seem to have better fuel economy than Zues. Surely this is one of the main reasons for specifying a pod drive system over shaftdrive? Anyone care to hazard a guess why IPS could be more economical than Zues? Is it the fact that the forward facing IPS props are more efficient?
Having said this, Zues looks like a thoroughly sorted drive sytem and plainly CMD have put a lot of thought into it's design
 
The report definitely indicated that the Zeus drive was Their choice!

To be honest, it would be my choice as well. I've always thought that forward facing props are a little vulnerable.

I would choose a boat fitted with the Zeus drive before an IPS system, even if the fuel consumption was a little worse. If I were to spend copious amounts of cash on a boat, the small difference in fuel consumption over each year would be small potatoes, compared to the other running costs.

I also think both technologies have a long way to go and for a used boat, would still prefer shaft drive for its ease of maintenance. If it were a new boat I was buying, I would be tempted to go for the Zeus rather than shaft or IPS, but for a used boat, with no MFR warranty, it would be a shaft drive system at the moment.

Nobody knows what problems will come to light in five or six years with either of these new technologies.

The report also has a very valid point, in that even if the Zeus was more expensive to buy, it is a more complete package, with everything you are likely to need.

Volvo have a habit of creating a situation where, what some people would call essential, they call an extra, just to raise a greater revenue from you!

So even on principle, it would be the Zeus drive for me!
 
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Anyone care to hazard a guess why IPS could be more economical than Zues? Is it the fact that the forward facing IPS props are more efficient?


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No facts between IPS and Zeus but I do have proof IPS uses a lot less than shaft drive.

Each weekend I went to the boat and turned the keys , my shafts turned as the fuel gauge fell.

Had I invested in IPS , I would not have suffered the same fuel bill.

Proof of IPS drive fuel savings

The owner of this IPS boat hardly spent a penny on fuel all season.

Rodman on the hard at Port solent , 41 foot ish flybridge described as
Ex demo..... /forums/images/graemlins/ooo.gif
Anyone know if it is still there and if it still has holes in where the IPS should be ?
 
Maybe someone should ask why Zeus needs an integral trim tab while IPS does not and what would happen if it was disabled? I suspect you would have a very sluggish boat that would take ages to get onto the plane.
 
IPS boats have trim tabs. See the image in DAKA's link above - the stbd tab is clearly visible. Including the tab within the pod makes installation simpler for the builder and should lower the overall cost vs having to procure and install trim tabs separately.
 
IPS boats run conventional trim tabs like most other boats but can get on the plane perfectly well without them. Zeus has a built in trim tab and although I'm not 100% I have heard it's because it needs it and not because it's a nice option to have.

I know there was a side by side comparison between Zeus and IPS on a pair of Doral Alegria 45's last summer.

Zeus had a 480hp
IPS was 435hp
Top speed was within .1 knot despite Zeus having more hp, IPS was so far ahead in acceleration that a comparison was not made to give the CMD people a chance to make some tweaks. I do not think a comparison was ever made so it would be good when an IPS version of the SC47 is launched and then Tony Jones could test this one as well.
IPS was around 10 to 15% more efficient but data was only taken from onboard electronics and not flow meters.
Apart from the above points they were fairly alike with boat testers saying the boats had the same feeling and sound characteristics.
 
I guess we can't have our cake, and eat it. We've criticised MBY for sitting on the fence and never declaring winners in their boat shoot outs, so have to say fair play to them for saying one system is better than another, when both co's are major advertisers?
 
I have not yet had the opportunity to read the article so I may be shooting from the hip.

The secret would be understanding each % engine load, you can read it with Smartcraft and I assume so with EVC. However it sounds like the Zeus boat may have been under propped if there was a huge difference in acceleration, 435 Vs 480 Hpm should not make that much difference. In boats back to back is rarely back to back.

For a fair comparison in terms of fuel consumption I would expect to see both boats pulling the same load, around 90% with both having a totally clean bottom, and would read what consumption the Smartcraft/EVC displays are giving.

Flow meters are a thing of the past with electronic engines. However I wonder if MBY people have been told that they need to multiply by 1.20094 if they were using the GPH figure off Smartcraft. Vs EVC.
 
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For a fair comparison in terms of fuel consumption I would expect to see both boats pulling the same load, around 90%

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But that's not a fair comparison either, cos one boat may be going faster and we all know the speed/mpg curve is exactly that, a curve. Some of the early comparisons between IPS and shafts were fundamentally flawed, cos they measured fuel burn and mpg at the same rpm, completely ignoring how fast the boat was going. IMO for a fair comparison you need to measure mpg with both boats at the same speed, 'cos that's what really matters to the user, and you can (nearly) always improve efficiency by just going slower.
 
Houghn,

You missed my point slightly, remember props drive boats not engines, if there was a big difference in engine loadings for similar speed then it is just possible that the prop match was not right which would reflect in propulsive efficiency and therefore fuel consumption.

However I will get hold of the article tomorrow and reserve judgment until then.
 
the other factor of course is that the engines are not the same, cummins v volvo
in my opinion both systems are flawed for my sort of use, ie mucking about in poole harbour making most of the shallows.
plus stern drive is also more efficient than the pair of them, shame they cant do more powerful versions.
plus cummins have done independantly steered stern drives to with joystick, skyhook etc
plus lot easier to free of ropes from stern drives than pods or shafts, you dont need a lift out
volvo wins on reputation and theres a volvo agent in every port, cmd doesnt yet have this backup
but recent new volvo stuff is letting them down and paying a massive amount extra for joystick and skyhook is a real downer on them
 
yeah ZF will be having a laugh on all this, as it produceses both systems
another factor here one forgets is what a boat is designed for
for e.g. I think the Sealine will fair better with Zeus, which need prop pockets / tunnerl drives for better efficency
on the other hand IPS needs a low angled vee on the forward section, infront of the props

IPS does plane before then Zeus due to the forward facing props, still not better then shafts without tunnels though

but now even Arnesons SD have good low planning speed of about 15 knots
 
I have had a chance to scan the article in MBY, very readable.

All a little subjective with Sealine SC 47 Zeus Vs Sunseeker 47 on shafts Vs Sunseeker 47 with IPS. Apples oranges bananas, but all still excellent reading.

Americans think the U.S is the centre of the universe so Smartcraft reads in U.S. gallons with no option of Imperial gallons that's why I asked if the GPH figure had been multiplied by 1.20094 as the test data states 'GPH and MPG figures use Imperial gallons'

In reality I doubt if there is a huge difference between Zeus and IPS efficiency forward or rearward facing props..I think we can leave that to marketing folks, more of a which way water goes down the plug hole left or right handed.

I am not a person who relishes the idea of immersing oil filled gear boxes in salt water be it stern drive or pod, however I suspect Volvo will up their technical game and look seriously at their parts pricing, Cummins builds around 350,000 ISB/QSB motors annually which makes for competitive parts pricing.
 
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Americans think the U.S is the centre of the universe so Smartcraft reads in U.S. gallons with no option of Imperial gallons that's why I asked if the GPH figure had been multiplied by 1.20094 as the test data states 'GPH and MPG figures use Imperial gallons'

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That's just the kind of thing our boaty magazines would cock up so it's a good point
 
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Americans think the U.S is the centre of the universe so Smartcraft reads in U.S. gallons with no option of Imperial gallons that's why I asked if the GPH figure had been multiplied by 1.20094 as the test data states 'GPH and MPG figures use Imperial gallons'

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That's just the kind of thing our boaty magazines would cock up so it's a good point

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Regarding concerns about the validity of the fuel consumption figures, I know how Dave Marsh measures and checks these, and it’s unlikely that they are wrong. Firstly, wherever possible (as it is with Zeus’s SmartCraft ) he configures the onboard instrumentation to display the fuel burn in litres per hour, specifically to avoid the Imperial/US gallon issue mentioned. Secondly, the maximum recorded fuel burn is always checked against the engine manufacturer’s fuel consumption data at maximum RPM, to ensure that MBY’s figures appear sound.

The figures are always an average of a two way run (another cross-check) even when they are recorded in tide free and wind free conditions – this applies to the speed too which is measured using a minimum of two GPS sets. If it’s available, the MBY fuel burn figures are also checked against the boat builder’s and/or the engine manufacturer’s own on-water test data.

That seems reasonably thorough to me. David would probably be mortified by the idea that a Imperial/US gallon thing is ‘just the kind of thing our boaty magazines would cock up’, as Deleted User puts it.

Best wishes
TJ
 
Re trim tabs, the fairline targa 44 is fitted with IPS and has the auto trim tab set up I have from mente marine. This apparently is to prevent chine walk on IPS boats which would otherwise presumably need you to constantly trim the boat manually. This probably answers the question why Merc fit trim tabs to their system. Nice boat that targa 44, must take one for a test drive one day. /forums/images/graemlins/confused.gif /forums/images/graemlins/grin.gif
 
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