IPS vs Shafts

[Nick1150]

Hello to all,

I am in the market for a 45-50ft boat, after 2002-2004 era, with electronic controls, mainly in the fly or coupe category (need the aft sliding door).

During my research, I found a boat with IPS drives. This kind of propulsion was not in my list, as an old dog, but one has to admit that there are advantages, and the world goes forward.

So my question is to those owning a boat with IPS propulsion.

How IPS drives handle corrosion, given that my boat will stay definitely 11 months per year in the water? Any issues what so ever? I suspect there are threads but would you buy an IPS driven boat or a Shaft driven boat at the 45-50ft fly or coupe category, and why?

Thanks

 

[westernman]

I am also interested in learning more about the costs and reliability of IPS drives. I searched for some information and there is a lot of negative information about servicing costs, seals leaking and entailing a very expensive major overhaul etc etc.

Would it be fair to say that post 2012 or so, that

1. IPS drives are 100% reliable provided that maintenance has been done by the book?
2. The yearly maintenance does not add much to the cost of normal engine maintenance, but it is not readily DIY?
3. There is a major maintenance every 5 years which adds about 1K euros per engine to a normal shaft drive yearly maintenance bill (changing all the seals)?

I would be grateful for any insights on maintenance costs and the likelihood of leaky seals and needing a major overhaul.

 

[BruceK]

Fine! I will be first to climb the firewood to be tied to the stake. IPS is the way forward but would I buy a 2nd hand 16 year old boat with IPS? No. Thats like buying a 16 year old second hand Land Rover. You just know you will be footing its midlife crisis repair bills in the near future. Outdrives are bad enough but at least they're cheap.

 

[jrudge]

Firstly I have nil first hand experience of IPS. There have been several threads.

All boats go wrong and IPS is no exception. IPS contains a load of electronics and other clever stuff and from what I can see it is mostly reliable. I know an engineer in Mallorca who has no troubles with them.

HOWEVER if they do go wrong the bill is large and you are pretty much tied to the Volvo Dealer network.

The is a facebook group - Volvo Penta Victims and you will find many tales of woe on there and problems that either keep coming back or just cant be fixed.

The Volvo tech is not an electronics engineer and just does what the computer tells him, Modern cars are the same but they are mostly used daily and dont live in salt water so we tend not to notice. They also only have one engine!

I would not scaremonger about them but I would go into it with your eyes wide open as to the potential bill - made far worse by the fact that the engineer in the yard is unlikely to be able to fix it so you are on main dealer rates - which is not usual for older boats.

Would I buy one? To be honest - no.

 

[Portofino]

No not an old one .
New maybe if the boat was going to be flipped when the warranty ran out .
Retired sways it towards new IPS, because show stoppers don’t really matter as much as explaining to wife + kids “ Dads boats broken again “ .
Time poor or cash poor avoid = spoil your enjoyment .

Shafts are in engineering terms to simplest way to go and you are not tied to a marque specialist.
They are also easier on the spend because of the predictably of work .You can budget and plan .
Ie cutlass bearings don’t go bang , they wear pretty much like a rubber tyre .Like tyre tread wearing you get play gradually .
Shaft seals last for ages, again A N Other yard can do them .They start drip and it’s up to you to time line the replacements

You will use more fuel , or turned around spend more on fuel , buts that’s entirely discretionary, distance and the speed you choose to travel at .

Another thing to add to Bruce’s / JRudges posts……Volvo !
Yep do you really want one ? Talking about the motor attached to the pod , not just the pod itself .

D 12 excepted , that’s a good un .Usually podded on 60/70 ftrs , a 40/50 ftr will come with the aged D6 incumbrance.
Thats a double whammy in terms of buying hassle .

Imho go for a Cummins , CAT or MAN ( they did a 8.3 L ) boat about 7-9 L in a 40-50 ftr .

I came from a KAD 300 DPH legged boat to a MAN 12.8 L in line 6 of 700 Hp on straight shafts and have never looked back .

Done zero maintenance of the stern gear / shaft seals in the past7/8; seasons .It’s a 2002 boat so same era as you are looking .
Just anodes , etc .+ annual lub DIY filter changes .The DIY bit means you save £/€ Etc .

Had one tiny sensor fail at 950 hrs , needed a new injector assembly , but was no show stopper boat still ran .€2000 by MAN to fix .
Last two yrs bills were approx €300 for the oil , €150 for the various filters aggregated out to inc a 3 yr air filter change .
About 60 hrs pa .That’s it , that’s my engine bills for the past 7/8 seasons .

I am sure the other marques of none Volvo under 10L for boat the size you are looking at could , stress could be similar .??

Just to finish @ a recent near end of season pleasant surprise they reached rated rpm 2200 at WOT at 100%load at manufacturers fuel burn .


Not bad aged 20 , life in the old girls yet .@ 1058 hrs

 

[Portofino]

Not gonna get into parking .
Its like advising your 17 y old that’s passed there test to get a car with surround cameras and parking assist .
You don‘t need gadgets to park .

 

[DAW]

Although I've always owned boats with shaft drives, I have friends with IPS boats and so have some real world experience and knowledge. Two of my last three boats have had Volvo Penta engines (D12-750 and now D13-900) and I've also owned boats with MAN engines. I will admit I don't really know much about outdrives, but from what I've seen these mostly tend to be used on boats which are smaller than those featuring IPS, so I think the most relevant comparison is to shaft drive.

Based on my experience, the modern generation of IPS clearly beats traditional shafts on overall efficiency, top speed and fuel economy. From what I've seen and experienced, boats with IPS are generally lighter, more responsive and manoeuvrable at low speed, but feel slightly less stable cornering at higher speeds and don't perform as well in adverse conditions. I suspect this is mainly due to the shape of the hull and other design decisions rather than the drive system itself. With IPS you usually have a relatively flat bottom and a shallow V, whereas with shafts you often have tunnels and a slightly deeper V. With IPS, the engines are also usually pushed further back in the boat to increase space for accommodation, altering the centre of gravity with the result that the bow tends to ride higher. These factors inevitably have a significant effect on handling and drag characteristics.

For most people I'm not sure an exhaustive comparison of the performance difference between shafts and IPS is really worth the effort ... How many people really throw around a 40-60 foot boat enough to worry or care about high-speed manoeuvrability or stability? A combination of IPS/gyro/active trim tabs makes the real world difference to shafts/fins in less than perfect conditions negligible, and most people never venture out in really bad weather. The relatively modest difference in fuel consumption doesn't really make a dent in the overall costs of owning and operating a 40-60ft motorboat. The joystick manoeuvring capabilities of IPS used to be a big advantage, but you can now have this on shaft drive boats, and I'm still in the camp that believes you need to know how to drive the boat without modern joystick technology in case it fails. I would never buy a boat of this size without a bow thruster (and ideally a stern thruster) or rely solely on IPS to control the boat in windy conditions. It's also a little frightening to see how much larger IPS-driven flybridge boats (Pearl 62, Absolute Navetta 58, etc.) rock back-and-forth when they are manoeuvring in the marina.

In terms of mechanical reliability and servicing costs, I've not heard of any horror stories on IPS boats that are looked after properly. The VP dealer that looks after my boat says they don't have any more issues with IPS boats than they do with their shaft driven equivalents. The maintenance programme for the transmissions is different and some of the annual inspections and routine maintenance works have to be done with the boat out of the water, but from what I've heard from friends the additional cost of this is modest and completely manageable.

I've never really understood the comments about problems with the Volvo Penta dealer network and the need to have free access to independent engineers. My experience of service and support from VP and MAN agents is about the same and generally good in both cases. I've used authorised and independent agents with good and not so good results in both cases. If anything the official VP dealers and parts costs have been slightly cheaper than their MAN equivalents. The issues of increasing complexity, additional reliance on electronic engine management systems, etc. are common to all of the engines used on modern boats and so servicing them will be an issue for all of them as they age, whether on shafts or IPS.

 

[Nick1150]

Portofino, this thread has nothing to do with the IPS joystick....

 

[westernman]

Another thing to add to Bruce’s / JRudges posts……Volvo !
Yep do you really want one ? Talking about the motor attached to the pod , not just the pod itself .

There is not much choice in the under 50ft range which is not Volvo.
The question is whether to exclude IPS from possible contenders.
If you exclude Volvo there is not much left.

 

[Bouba]

It’s been quite a few years since virtually all mid size motorboats were IPS...a trip to any boat show would have told us that...so were are all the secondhand shaft boats going to come from?...and just as mysterious, where are all our IPS owning forumites?

 

[MapisM]

so were are all the secondhand shaft boats going to come from?
...and just as mysterious, where are all our IPS owning forumites?

All busy trying to sell their boat, and find a used one on shafts.

 

[oldgit]

Having actually used and even considered buying a boat with IPS think it depends on what you want in a boat.
Found it no easier to moor in confined spaces than a boat with twin shafts, possibly it simply depends on your personal skills and confidence and what you are used to.
As for the much touted superior economy, fine if you go everywhere flat out.
Do what the majority do ie
mostly poodle around with the odd blast and suspect the fuel saving start to vanish.
Was actively looking at a Rodman 41 with a 1000 hour service coming up.
This was not a major service ?
The amount of money required for the bits and pieces plus of course the compulsory lift out killed this purchase stone dead.
14 litres of oil each engine @ £375.00 per 20 litres plus seals swap and other stuff.
There is a firm advertising a exchange refurbed IPS leg for around £ 25 K so the possibility of DIY is there.
Will shortly be helping to do a bit of basic work on a boat with IPS, A/F anodes etc, should be an interesting day.

 

[westernman]

Having actually used and even considered buying a boat with IPS think it depends on what you want in a boat.
Found it no easier to moor in confined spaces than a boat with twin shafts, possibly it simply depends on your personal skills and confidence and what you are used to.
As for the much touted superior economy, fine if you go everywhere flat out.
Do what the majority do ie
mostly poodle around with the odd blast and suspect the fuel saving start to vanish.
Was actively looking at a Rodman 41 with a 1000 hour service coming up.
This was not a major service.
The amount of money required for the bits and pieces plus of course the compulsory lift out killed this purchase stone dead.
There is a firm advertising a exchange refurbed IPS leg for around £ 25 K so the possibility of DIY is there.

The question of IPS or not has nothing to do with the ease of maneuvering for us.

I am used to med parking a 20m LOA single screw heavy long keel boat without bow thruster which has a mind of its own in reverse. So anything at all is easy after that.

It comes down to the Admiral. The IPS boats have great accommodation for their size. May be comparable to that of a shaft boat as much as 2m longer. The Admiral likes that full width centre master you can get with an IPS boat.

The trade off I guess comes down to a smaller IPS boat vs a larger boat on shafts.
The larger boat costs more to park, to lift, to antifoul and will use more fuel.
Does that cancel out the additional maintenance costs of an IPS drive vs a shaft drive?

I agree, the difference in fuel used is going to be negligible in overall cost total.

 

[oldgit]

MBM boat test on the Rodman 41 proclaimed that its third cabin was only possible due to IPS allowing the extra space in the hull.
The shaft version also has the third cabin.
One advantage of the IPS was how quiet the boat was due to engines not being immediately under the saloon.

 

[Elessar]

No not an old one .
New maybe if the boat was going to be flipped when the warranty ran out .
Retired sways it towards new IPS, because show stoppers don’t really matter as much as explaining to wife + kids “ Dads boats broken again “ .
Time poor or cash poor avoid = spoil your enjoyment .

Shafts are in engineering terms to simplest way to go and you are not tied to a marque specialist.
They are also easier on the spend because of the predictably of work .You can budget and plan .
Ie cutlass bearings don’t go bang , they wear pretty much like a rubber tyre .Like tyre tread wearing you get play gradually .
Shaft seals last for ages, again A N Other yard can do them .They start drip and it’s up to you to time line the replacements

You will use more fuel , or turned around spend more on fuel , buts that’s entirely discretionary, distance and the speed you choose to travel at .

Another thing to add to Bruce’s / JRudges posts……Volvo !
Yep do you really want one ? Talking about the motor attached to the pod , not just the pod itself .

D 12 excepted , that’s a good un .Usually podded on 60/70 ftrs , a 40/50 ftr will come with the aged D6 incumbrance.
Thats a double whammy in terms of buying hassle .

Imho go for a Cummins , CAT or MAN ( they did a 8.3 L ) boat about 7-9 L in a 40-50 ftr .

I came from a KAD 300 DPH legged boat to a MAN 12.8 L in line 6 of 700 Hp on straight shafts and have never looked back .

Done zero maintenance of the stern gear / shaft seals in the past7/8; seasons .It’s a 2002 boat so same era as you are looking .
Just anodes , etc .+ annual lub DIY filter changes .The DIY bit means you save £/€ Etc .

Had one tiny sensor fail at 950 hrs , needed a new injector assembly , but was no show stopper boat still ran .€2000 by MAN to fix .
Last two yrs bills were approx €300 for the oil , €150 for the various filters aggregated out to inc a 3 yr air filter change .
About 60 hrs pa .That’s it , that’s my engine bills for the past 7/8 seasons .

I am sure the other marques of none Volvo under 10L for boat the size you are looking at could , stress could be similar .??

Just to finish @ a recent near end of season pleasant surprise they reached rated rpm 2200 at WOT at 100%load at manufacturers fuel burn .

View attachment 142982
Not bad aged 20 , life in the old girls yet .@ 1058 hrs

Friend of mine is facing a £15k bill to replace a gasket on his MAN engine. Immaculately maintained boat. As anecdotal as your experience and adds nothing to the debate.

 

[oldgit]

It’s been quite a few years since virtually all mid size motorboats were IPS...a trip to any boat show would have told us that...so were are all the secondhand shaft boats going to come from?...and just as mysterious, where are all our IPS owning forumites?

Wandering around the marina in Cala d Or and looking at boats on the hard, suggests IPS not as all conquering as some would like to have us believe.
In fact in a location and with the size of boat most likely to have IPS, very few boats seemed have it, one or two did have the Zeus version.
Most were on shafts.
Money no object why not IPS however for most the cost of maintenance matters.

 

[MapisM]

Based on my experience, the modern generation of IPS clearly beats traditional shafts on overall efficiency, top speed and fuel economy.

Based on which experience, exactly?
The only 100% clear thing is how good the VP marketing has been at making most folks believe such BS.

Let's make a bit of numbers-based comparison, for a change.

As an IPS contender, I think it's fair to pick a boat built by Absolute, whose boats are widely recognized as among the most optimized only for IPS propulsion.
One of their more recent models is the 56 Flybridge, which was tested last June in The Boat Show channel.
As a shaft contender, I'm using a boat which I happen to know pretty well, because I own one of them: the DP56, a very traditional flybridge on shafts, designed in the late 90s.
Different from the Abs in many ways of course: no hard top, no hi/lo platform, no hull windows, etc. - we're talking of almost a quarter of a century difference in design, after all.
But almost perfectly comparable in all the numbers that really matter, when talking of overall efficiency: dimensions and displacement.
Actually, if anything, both beam and displacement are actually a bit larger in my boat, but not enough to even mention them.

The powerplant is instead very different, with 8 liters 600hp engines + IPS on the Abs, vs. 15 liters 800hp engines + shafts in mine.
It's interesting to note that the Abs powerplant is what VP call "IPS 800", claiming that it's comparable with 800hp engines on shafts.
So, let's see how the concept "IPS clearly beats traditional shafts on overall efficiency, top speed and fuel economy" materializes into numbers (or not!).
Unfortunately, Bulleri in his test didn't give a lot of numbers through the whole utilization range, but those which he gave are enough to draw some interesting conclusions.
1) fuel burn at the suggested cruising speed of 18 kts: 8,4 liters/Nm.
2) max speed achieved with 30% load: 27,5 kts, with a fuel burn of 9 L/Nm.

Now, my typical cruising speed is actually a bit higher - anywhere between 20 and 25 kts.
But within this range, the fuel burn goes from 7 to 8 L/Nm.
In other words, I still burn slightly less (8L) at 25 kts than the Abs does at 18 kts (8,4L), and at 20kts I burn 17% less.
"Whiskey Tango Foxtrot?" springs to mind...
Oh, and ref. the "IPS 800" claim, the max speed in my boat is 33 kts, with a fuel burn of 9,5 L/Nm.
In other words, a 6 % higher fuel burn but at a 20% higher speed.
Clearly, the fuel burn in L/hr is much lower in the Abs (at WOT, 250 vs. 320 of my boat, consistently with the overall 400hp higher output).
But that's NOT a measure of efficiency, for very obvious reasons - liters per Nm is!
And mind, the data related to my boat are at full load, not 30%.

Then again, I don't have any joystick to play with...

 

[Portofino]

Portofino, this thread has nothing to do with the IPS joystick....

That’s why I said in post #6 I will quote it here save you looking
“Not gonna get into parking .”
It is how ever an added add vantage to some .You did not qualify your exact mobo experience .
Thx for the additional clarity on your position .As I thought btw .

 

[Bouba]

Based on which experience, exactly?
The only 100% clear thing is how good the VP marketing has been at making most folks believe such BS.

Let's make a bit of numbers-based comparison, for a change.

As an IPS contender, I think it's fair to pick a boat built by Absolute, whose boats are widely recognized as among the most optimized only for IPS propulsion.
One of their more recent models is the 56 Flybridge, which was tested last June in The Boat Show channel.
As a shaft contender, I'm using a boat which I happen to know pretty well, because I own one of them: the DP56, a very traditional flybridge on shafts, designed in the late 90s.
Different from the Abs in many ways of course: no hard top, no hi/lo platform, no hull windows, etc. - we're talking of almost a quarter of a century difference in design, after all.
But almost perfectly comparable in all the numbers that really matter, when talking of overall efficiency: dimensions and displacement.
Actually, if anything, both beam and displacement are actually a bit larger in my boat, but not enough to even mention them.

The powerplant is instead very different, with 8 liters 600hp engines + IPS on the Abs, vs. 15 liters 800hp engines + shafts in mine.
It's interesting to note that the Abs powerplant is what VP call "IPS 800", claiming that it's comparable with 800hp engines on shafts.
So, let's see how the concept "IPS clearly beats traditional shafts on overall efficiency, top speed and fuel economy" materializes into numbers (or not!).
Unfortunately, Bulleri in his test didn't give a lot of numbers through the whole utilization range, but those which he gave are enough to draw some interesting conclusions.
1) fuel burn at the suggested cruising speed of 18 kts: 8,4 liters/Nm.
2) max speed achieved with 30% load: 27,5 kts, with a fuel burn of 9 L/Nm.

Now, my typical cruising speed is actually a bit higher - anywhere between 20 and 25 kts.
But within this range, the fuel burn goes from 7 to 8 L/Nm.
In other words, I still burn slightly less (8L) at 25 kts than the Abs does at 18 kts (8,4L), and at 20kts I burn 17% less.
"Whiskey Tango Foxtrot?" springs to mind...
Oh, and ref. the "IPS 800" claim, the max speed in my boat is 33 kts, with a fuel burn of 9,5 L/Nm.
In other words, a 6 % higher fuel burn but at a 20% higher speed.
Clearly, the fuel burn in L/hr is much lower in the Abs (at WOT, 250 vs. 320 of my boat, consistently with the overall 400hp higher output).
But that's NOT a measure of efficiency, for very obvious reasons - liters per Nm is!
And mind, the data related to my boat are at full load, not 30%.

Then again, I don't have any joystick to play with...

Pods and forward facing propellers must have some efficacy...otherwise all the mega cruise ships wouldn’t use them...

 

[Portofino]

There is not much choice in the under 50ft range which is not Volvo.
The question is whether to exclude IPS from possible contenders.
If you exclude Volvo there is not much left.

Did you miss the age preference stated by the op ? We are not talking now , but nearer 20 y ago + or - a couple of yrs .
The gentlemen in me to save you scrolling back , quote the OP
“ I am in the market for a 45-50ft boat, after 2002-2004 era,”

Theres a plenty of none VP .