IPS vs Shafts

[Portofino]

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?

As per above

“ I am in the market for a 45-50ft boat, after 2002-2004 era,” quoting the OP .
Whats todays sojourn around a boat show got to do with this era ?

 

[Portofino]

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

Join me on the naughty step P

 

[Bouba]

As per above

“ I am in the market for a 45-50ft boat, after 2002-2004 era,” quoting the OP .
Whats todays sojourn around a boat show got to do with this era ?

When the general subject of IPS started, I thought I’d chime in

 

[Portofino]

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.

Not so sure it’s up to the Op he’s the one who hold the decision .
Old IPS .Remember folks .
@ DAW yes new is good .As I said new , new with warranty or even a 2020 vs I would give serious thought .
My Admiral would want a test drive and if it slams ( you kindly ventured into hull form - Thx ) so for me , the two of us it’s unlikely .
How ever just to repeat sorry folks a early IPS no chance .
How olds the oldest btw ..any one know .


2007 Porto 47 on IPS ….blame DAW for this Ps.
“He started the hull form debate sir “

At ellessar …I have saved £ over the outdrives maintenance.
Yes any one can pick a big bill esp for CR boats .
The pre CR , likely to be in the OPs hunting ground are better .
A older CAT , Cummins , MAN or MTU circa 2002-2004 is a better bet than a D6 + plus version A or B .

Its not todays gander at the SIBs it s two decades ago .What am I missing responding to get this reaction ?

 

[MapisM]

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

Pods on displacement hulls are fine, and they have been around for decades, also on tugs and workboats.
But it's an apple vs. oranges comparison, because on all those hulls they rotate along a vertical axis, hence not introducing an additional listing force component upon steering.
As they do when installed in planing V hulls, to the point of forcing builders to adapt their hull shapes to the propulsion needs.
So, what happens with IPS is that a propulsion with an inherent potential of higher efficiency actually demands inefficient hulls to be installed.

If this weren't true, why on earth should my 20yo boat be more efficient that one of the most modern IPS incarnations, at a 98% comparable size and weight - whereas the residual 2% is actually more "favourable" to the Abs?
Mind, in fairness there are also other reasons why boat design moved from the "hull first, the rest will follow" philosophy to the modern "we want to fit this and that, and the hull must accomodate everything" approach.
But IPS has been one of the most contributing factors, that's for sure.

 

[Portofino]

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

Rear facing and they use them to manoeuvre on to tiny Caribbean islands with in a fag papers thickness gap between a competitors boat .Any additional maintenance overheads can be amortised over the 2000 + punters per week per trip .
Or hire more Philippino crew. Both work .

 

[Portofino]

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...

They buy them for the vast mid cabin or other internal space utilisation.
Joy stick comes with it .It’s not a - ve .
Fuel burn I think we all agree is way down the must haves .
With a boat , a poor hull in the chop , they ain’t gonna be racking up the hrs .So benefiting from any real or perceived fuel saving .
Aside it’s one of the smallest things even at todays prices in the gen scheme of cost of ownership.

Back on topic …..say the OP picked up a aged 2004 IPS with the Admirals must have mid cabin , …..how is he gonna offload it when it’s 25 Y r old and a history file 2-3 x the size of when he bought it ?

 

[Portofino]

Pods on displacement hulls are fine, and they have been around for decades, also on tugs and workboats.
But it's an apple vs. oranges comparison, because on all those hulls they rotate along a vertical axis, hence not introducing an additional listing force component upon steering.
As they do when installed in planing V hulls, to the point of forcing builders to adapt their hull shapes to the propulsion needs.
So, what happens with IPS is that a propulsion with an inherent potential of higher efficiency actually demands inefficient hulls to be installed.

If this weren't true, why on earth should my 20yo boat be more efficient that one of the most modern IPS incarnations, at a 98% comparable size and weight - whereas the residual 2% is actually more "favourable" to the Abs?
Mind, in fairness there are also other reasons why boat design moved from the "hull first, the rest will follow" philosophy to the modern "we want to fit this and that, and the hull must accomodate everything" approach.
But IPS has been one of the most contributing factors, that's for sure.

Because it’s the Fords Cortina 1.3 vs the 2.0 argument .
Your 16 L 8 banger purring away at 1850 rpm vs his 5.5 L 6 banger screaming at 3500 rm …..plus the 3or 4 x torque difference via a g box to swing a bigger prop .

 

[oceanfroggie]

Personally I prefer the gentle reliable precision of shafts, IPS rocks boat too much and too much jerking when manoeuvring. More power being deployed than would be necessary with shafts.

 

[Elessar]

They buy them for the vast mid cabin or other internal space utilisation.
Joy stick comes with it .It’s not a - ve .
Fuel burn I think we all agree is way down the must haves .
With a boat , a poor hull in the chop , they ain’t gonna be racking up the hrs .So benefiting from any real or perceived fuel saving .
Aside it’s one of the smallest things even at todays prices in the gen scheme of cost of ownership.

Back on topic …..say the OP picked up a aged 2004 IPS with the Admirals must have mid cabin , …..how is he gonna offload it when it’s 25 Y r old and a history file 2-3 x the size of when he bought it ?

My crap boat with deficient deadrise (or somesuch nonsense) has done 1050 hours and I’ve had it 18 months. It was 750 hours when I bought it.
Of course it won’t do any hours ? just 200 a year average so far in my ownership.

 

[MapisM]

Personally I prefer the gentle reliable precision of shafts, IPS rocks boat too much and too much jerking when manoeuvring. More power being deployed than would be necessary with shafts.

I've seen a fair bit of IPS boat docking, and I fully agree with you, generally speaking.
But after actually maneuvering an IPS powered boat, I came to the conclusion that to a large extent this is the helmsmen's fault - albeit sort of triggered by the joystick possibilities.
I mean, the joystick for many people is a dream materialized: a boat that reacts to the controls instantly, almost as if it were a car.
So, instead of maneuvering the boat and give her time to react (as anyone used to shafts normally do), they just push the joystick further when the boat doesn't move as fast as they want.
Most often than not, with the result of having to push to the opposite side after a few seconds, because the boat eventually moves more than desired.
But if you use the joystick gently, taking your time and avoiding contrasting movements, the boat reacts in a much more civilized way.
In fact, I also tried to dock the same IPS boat with the levers alone, without even touching the joystick, and she proved as maneuverable as any shafts boat.
Trouble is, when I tried to tell the owner to forget the joystick and use just the levers in anything but strong side wind (where the joystick can indeed help, on boats with no bow thruster), he laughed at me and argued that he wouldn't have bought the boat at all, if it weren't for the joystick...

 

[Elessar]

I've seen a fair bit of IPS boat docking, and I fully agree with you, generally speaking.
But after actually maneuvering an IPS powered boat, I came to the conclusion that to a large extent this is the helmsmen's fault - albeit sort of triggered by the joystick possibilities.
I mean, the joystick for many people is a dream materialized: a boat that reacts to the controls instantly, almost as if it were a car.
So, instead of maneuvering the boat and give her time to react (as anyone used to shafts normally do), they just push the joystick further when the boat doesn't move as fast as they want.
Most often than not, with the result of having to push to the opposite side after a few seconds, because the boat eventually moves more than desired.
But if you use the joystick gently, taking your time and avoiding contrasting movements, the boat reacts in a much more civilized way.
In fact, I also tried to dock the same IPS boat with the levers alone, without even touching the joystick, and she proved as maneuverable as any shafts boat.
Trouble is, when I tried to tell the owner to forget the joystick and use just the levers in anything but strong side wind (where the joystick can indeed help, on boats with no bow thruster), he laughed at me and argued that he wouldn't have bought the boat at all, if it weren't for the joystick...

IPS boats are lovely to manoeuvre if you are skilled in outdrive boats and you ignore the joystick.

 

[Portofino]

My crap boat with deficient deadrise (or somesuch nonsense) has done 1050 hours and I’ve had it 18 months. It was 750 hours when I bought it.
Of course it won’t do any hours ? just 200 a year average so far in my ownership.

So you are agreeing with me in a round about ( even more obtuse than me —— that’s a compliment btw ) that the residuals of a high hr early IPS is gonna be an issue at off load time .
Or I read a bottomless pit of expenditure to actually do 200 hr Pa ? ….I said 2-3 x the SH file size …but how bigger difference is yours going be with running a 20/yr ish IPS on 1000 hr IPS s ? ……a forum first ?
They say a pic or two paints a 1000 words .




Can‘t see a VP D6 + IPs pods going this long .
Perspective
For me until about Queens age ( sorry/mods )
Ellasar Charles age ?
Does really actually matter ,= nope .What natters in a game of boat serious boat maintenance if you drop!the big bills .
Sure behind ( a sale ) there a a bit of smoke and mirror’s hidden maintenance issues , but you factor that into offer price .
A 20;yr old boat is is RISK .
A VP with pods = You tell me ?

 

[MapisM]

IPS boats are lovely to manoeuvre if you are skilled in outdrive boats and you ignore the joystick.

Yup, that's also my (very limited) experience.
Trouble is, many IPS powered boats (including the one I tried) are built with no bow/thruster, so you can only use the joystick, whenever on a comparable shafts boat you could rely on the b/t.
In this respect, I can see why many (most?) IPS powered boat owners become joystick addicts in no time.
To the point of calling the marina and ask for docking assistance with a RIB only due to faulty joystick...
Witnessed a few years ago, I kid you not!

 

[Portofino]

Those that have taken the plunge (any era ) have wanted to have IPS .
They were never backed into a corner or had a knife held against there throats .
Plenty of same money spend could have bought a straight shaft similar .Maybe without the owners mid cabin .
You only sleep in it any how. Why is it important ?

I mean folks still bought Citroens and Afla‘s anyhow in the 70s 80 s .,….the ownership realities did not matter back then for a few .
Same for aged stressed “aged “:IPS boats .

Fast Fwds 20 yrs and the dynamics have changed …but we are not talking NEW ,

 

[volvopaul]

I thought this post would turn up a few replies .
My view is that they are great when they are running , they were designed for specific boats in mind at the outset , they can make a small boat so spacious by allowing that full beam mid cabin .
I wouldn’t advise buying one as a keeper , look after them to the letter you could have trouble free boating , of the few I look after I’ve had one failure so far and that’s been a steering issue , sadly the part is out of stock so the owner had it repaired for less than the price meal out in London , but buy a dud and it’s a small fortune .
They still have all the woes of an outdrive and the complicated electronics can add a whole load more to the wallet , but we go boating for fun , there are some great boats around with them in (. Targa48 open) for example what a beautiful boat .

When you look that a new DPH drive is £9903 and vat it’s half the cost of a new IPS unit but I have customers boats like the V45 that eat drives in 4 /5 seasons plus the prop failures and water ingress issues in between, it soon makes the IPS/ Outdrive/ shaft debate become real reality .
Looking at older boats there’s no way I’d choose a nice used V45 over an older shaft drive V48 , I’d pay the mooring and the fuel bill any day .

 

[westernman]

Looking at older boats there’s no way I’d choose a nice used V45 over an older shaft drive V48 , I’d pay the mooring and the fuel bill any day .

Thanks for the feedback. Confirms my feelings. I find the potential for things to go expensively wrong rather scary.

 

[Portofino]

I thought this post would turn up a few replies .
My view is that they are great when they are running , they were designed for specific boats in mind at the outset , they can make a small boat so spacious by allowing that full beam mid cabin .
I wouldn’t advise buying one as a keeper , look after them to the letter you could have trouble free boating , of the few I look after I’ve had one failure so far and that’s been a steering issue , sadly the part is out of stock so the owner had it repaired for less than the price meal out in London , but buy a dud and it’s a small fortune .
They still have all the woes of an outdrive and the complicated electronics can add a whole load more to the wallet , but we go boating for fun , there are some great boats around with them in (. Targa48 open) for example what a beautiful boat .

When you look that a new DPH drive is £9903 and vat it’s half the cost of a new IPS unit but I have customers boats like the V45 that eat drives in 4 /5 seasons plus the prop failures and water ingress issues in between, it soon makes the IPS/ Outdrive/ shaft debate become real reality .
Looking at older boats there’s no way I’d choose a nice used V45 over an older shaft drive V48 , I’d pay the mooring and the fuel bill any day .

Whats your view on the OP s predicament then ?
A “ 2002 - 2004 “ IPs … Crock of shit or go for it ? .……….for sake it seems of the Admirals desirable mid cabin . For clarity I have not said she “ must have “ ,
Z
Can you report the hrs on said I PS any you have worked on ? For a aged boat …..just we ( the OP ) can sort the apples from the pears .
Thx in anticipation mindful if client confidentially .



I mean which nutter would buy an aged IPS circa 2020- 2004 or even earlier would buy an IPS boat .?
Who ? Where is the market ?

 

[Portofino]

Thanks for the feedback. Confirms my feelings. I find the potential for things to go expensively wrong rather scary.

Whats on your radar ?
let s have a thrashing .
Maybe start a new thread . “ my wife want s this from the next boat “
No shame .Been there mate .

 

[westernman]

Whats on your radar ?
let s have a thrashing .

Looking for something 40-45ft or so with two decent double cabins, decent saloon and galley, flybridge with space for decent size tender + sailing dinghy (lightweight but 4m long probably stacked under tender hanging out over stern), heating, air conditioning. Enough storage space for some e-bikes.
No need to go fast. Confortable for staying on board at anchor and cooking for a week at a time. Ideally with a boom for a flopper stopper for breaking the roll at some anchorages.

The closest to match to requirements at the moment is a Swift Trawler 44.

Admiral loves the central midships cabin on some IPS boats.