IPS fuel consumption

[kashurst]

Has anyone noticed that the fuel consumption on IPS driven boats doesn't seem to be materially better than shafts. Another review of Princess 42 v sealine F42 indicates IPS is no improvement other than packaging.
Any IPS owners out here care to comment or able to compare on fuel costs and servicing issues?

P.S.
Princess is still a much better looking boat though...

 

[volvopaul]

Has anyone noticed that the fuel consumption on IPS driven boats doesn't seem to be materially better than shafts. Another review of Princess 42 v sealine F42 indicates IPS is no improvement other than packaging.
Any IPS owners out here care to comment or able to compare on fuel costs and servicing issues?

P.S.
Princess is still a much better looking boat though...

Quite right, I was talking to an IPS targa 44 owner who was asking me the mpg question, he had traded in a shaft drive boat of similar stature with a flybridge, the IPS boat is no better than shafts on fuel, the servicing is twice as much, the boats hull rides very bow up and doesnt seem to trim easy to rectify its attitude, so all in all hes paying a fortune to park his boat sideways. Take not the 44 is NLA on IPS, back to drives.

 

[oldgit]

Quite right, I was talking to an IPS targa 44 owner who was asking me the mpg question, he had traded in a shaft drive boat of similar stature with a flybridge, the IPS boat is no better than shafts on fuel, the servicing is twice as much, the boats hull rides very bow up and doesnt seem to trim easy to rectify its attitude, so all in all hes paying a fortune to park his boat sideways. Take not the 44 is NLA on IPS, back to drives.

Normally a fan of all things Volvo,but very much doubt that statement of no improvement in MPG over shafts which sounds a bit anecdotal to me..

Am all for improvements and advances in technology but marine advancement has always been through evolution not revolution and IPS is a classic example of this.
Still it does offer Volvo the chance to test stuff FOC courtesy of an army of keen "early adopters" of which there appear to be loads from certain sections of the boaty world.

 

[Grampus]

We have a Rodman 1250 with IPS 500. Comparing our actual fuel consumption with that published in MBM of September 2005 for the same boat on shafts, reveals some interesting contrasts.

The boat tested in MBM was a new, bare boat with 50% water and fuel and not a lot of other kit I would guess, whereas our boat was full of cruising equipment, genie, life rafts and 100% fuel and water all of which must make our real life boat ~1 to 1.5 tonnes greater displacement.

The MBM test boat on 'shafts' in its test condition of 'empty(ish)' gave the following:-
12.2kn - 1.63mpg; 15.5kn - 1.41mpg; 19.3kn - 1.25mpg; 23.1kn - 1.16mpg; 29kn - 0.87mpg; 31.9 kn - 0.81mpg.

Our IPS boat with full tanks and a boat/shedload of kit gives the following:-
7kn - 3.21mpg; 12.1kn - 1.18mpg; 14.5kn - 1.24mpg; 23.6kn - 1.26mpg; 29kn - 1.25mpg; 33kn - 1.26mpg.

So it would appear that at some value below around 12 to about say 16 knots, the unloaded 'shafts' boat provided better fuel consumption but at higher speeds the IPS was better.

As to service costs, comparisons are difficult but the only IPS service additions seem to be the synthetic gear oil for the legs, which costs around £400 for both pods/legs and the exhaust anodes which cost £100 for the pair. Without a comparison for the cost of gearbox oil for the shafts propulsion system, comparisons are difficult, perhaps Volvopaul would be the best to ask.

Full service for both IPS 500 through Philip Robinson Marine, my local and really excellent Penta service man in Belfast, is about £ 1650 plus VAT inclusive of parts and labour.

The great joy of the IPS system is that SWMBO is completely happy to drive and dock the boat which allows me to handle the lines and buoys etc. Also all the 'smelly' diesel and engine stuff is 'outside' below the cockpit sole, which again is a benefit for those, like my wife' who hates and loathes the smell of diesel and diesel engines.

IPS is just as happy to be driven and steered 'on the engines' but provides a similar benefit as do stern drives allowing vectored thrust.

It seems to me that the engineering and quality of the IPS units, the 'pod drives' themselves, is very well executed. The only serious service/warranty issues have been associated with the D6 engines themselves, where there seems to have been a tendency to let the bean counters determine engineering solutions at the expense of reliability and common sense.

However Volvo have been extremely quick and efficient in resolving the problems for which I am grateful to Volvo and the excellent Philip Robinson Marine (and no, I have no interest whatsoever with his company, other than being a happy customer).

I like the IPS system, it's quiet, not 'inside' the boat, thereby allowing a great hold/lazarette below the saloon sole; it's also really good at getting into places that seem impossible and make docking in strange and difficult places a breeze.

 

[oldgit]

Always fancied the 1250 since having a trip out on one at LBS,a proper boat.The IPS boat has just got to be more economical in the upper speed range.The real problem with IPS,is as with outdrives,the delayed maintaince problem which as the boat moves down the food chain with subsequent less affluent owners,simply will not get done.The other big disadvantage,is the inabilty to take the ground,which means a marina berth or nothing.

 

[Grampus]

Yes, you are absolutely right, longevity and reliability of complex electromechanical systems is a problem that just keeps increasing - but there seem to be ever fewer options for new boats.

I loved those wonderful Perkins diesels you could fix and service with a sledge hammer and screwdriver - my farming connections showing - but now it's all electronics and the need for constant attention to servicing and maintenance.

So it did not seem too much of a leap of faith to go the entire 'fly-by-wire' route as that was the way just about everything has become. Ultimately I looked on pod drives as a variant of the traditional stern drives with perhaps potentially fewer problems as the mechanicals are tucked away inside the sealed leg.

As for taking the ground, we chartered a Botnia Targa and did about 250 hours in her - that was a serious contender for a new boat, with its liftable stern-drives and fitted with a pair of legs to take the ground. Ultimately the advantages of the 1250 with its greater sense of light and useable space, combined with its dry, soft, semi-displacement ride outweighed the planing Targa and its stern drives.

The 1250 is a fine and safe sea boat for the North Irish Sea and with so many marinas, harbours and moorings here in the North, I hope never to feel the need for taking the ground - now that would be an expensive experience.

 

[Deleted User YDKXO]

I dont know specifically which figures you are referring to but I dont have much faith in fuel consumption figures quoted by magazines and I think you have to be careful about taking them at face value. The tests are mostly carried out on lightly loaded new boats over a short period of time using fuel flow measurement equipment. I would much rather trust long term real life consumption figures from owners like galps and his Rodman 1250
On the whole, I believe that IPS is more fuel efficient than shafts but apart from that, fuel efficiency is not the only advanatage of IPS. The other major advantage is that the engines are located further aft which frees up more space forward for accomodation. For example compare the palatial mid guest cabin on the F42 to the poky side guest cabin on the P42; thats a direct result of the F42 having IPS drives

 

[Bandit]

A lot of the magazine articles are not actual fuel burn figures but taken from the manufacturers spec on the power curve so show max fuel burn.

I understand that where the design and set up of the boat is optimised to IPS the fuel savings are considerable and the performance for lower installed power is good.

Sunseeker are basing two deigns a sportscruiser and a flybridge on teh same basic hull/ engine package with IPS.

 

[oldgit]

Less 4x4 more TX4

"As for taking the ground, we chartered a Botnia Targa"

O yes the mythical 4x4 of the sea........according to its own advertising department anyway and owners who have paid good money for one....A legend in its own lunchtime more like.Yet to see one used by any serious seagoing outfit and that does not count the Plod at Wapping because you will never see one of theirs the wrong side of the barrier.

 

[Kaste]

We have a Targa 44 GT - which we really like comparative to the T43 we traded in. As others have said, it enables my wife to berth the boat and provides more space etc. However, for a direct fuel comparison we cruised in company to St Vaast in May this year with V42 and travelled the exact distance together and obviously at the same speed and the V42 consumed about 5% less fuel than us.

I think that IPS fuel consumption is over hyped by the marketing peeps and that tends to lead towards disappointment with the system. Having stated that in all other aspects we are not unhappy with the boat but are looking forward to changing back to shafts, probably on a T47 if we can come come up with the readies.

 

[Deleted User YDKXO]

We have a Targa 44 GT - which we really like comparative to the T43 we traded in. As others have said, it enables my wife to berth the boat and provides more space etc. However, for a direct fuel comparison we cruised in company to St Vaast in May this year with V42 and travelled the exact distance together and obviously at the same speed and the V42 consumed about 5% less fuel than us.

I think that IPS fuel consumption is over hyped by the marketing peeps and that tends to lead towards disappointment with the system. Having stated that in all other aspects we are not unhappy with the boat but are looking forward to changing back to shafts, probably on a T47 if we can come come up with the readies.

If you're not unhappy with your IPS boat, why are you looking forward to going back to shafts? Just interested to know if you have experienced issues with IPS other than over hyped fuel efficiency

 

[Kaste]

If you're not unhappy with your IPS boat, why are you looking forward to going back to shafts? Just interested to know if you have experienced issues with IPS other than over hyped fuel efficiency

Probably as much to do with residual values on IPS boats as they seem to be more of a deterrent to buyers these days, as opposed the "the magic bullet" as it was portrayed to us when we purchased the boat. I realise that I ommitted to point out that a Princess Flybridge P42? also accompanied us to St Vaast with the same engines on shafts and obtained even better fuel consumption than the IPS or outdrives. Therefore my remark regarding the T47 on shafts was an OK option for us - meaning that not having IPS was not the end of the world.

Not had an other issues at all.

 

[Deleted User YDKXO]

Probably as much to do with residual values on IPS boats as they seem to be more of a deterrent to buyers these days, as opposed the "the magic bullet" as it was portrayed to us when we purchased the boat. I realise that I ommitted to point out that a Princess Flybridge P42? also accompanied us to St Vaast with the same engines on shafts and obtained even better fuel consumption than the IPS or outdrives. Therefore my remark regarding the T47 on shafts was an OK option for us - meaning that not having IPS was not the end of the world.

Not had an other issues at all.

Mmm, thats interesting because all the talk about IPS on this forum when IPS was introduced included armageddon type predictions that there would come a time when shaftdrive boats would be unsaleable on the used market because everyone would want IPS. I must admit I'm surprised if IPS is a deterrent on the used market. Maybe its concerns about future maintenance costs?

 

[volvopaul]

Mmm, thats interesting because all the talk about IPS on this forum when IPS was introduced included armageddon type predictions that there would come a time when shaftdrive boats would be unsaleable on the used market because everyone would want IPS. I must admit I'm surprised if IPS is a deterrent on the used market. Maybe its concerns about future maintenance costs?

I am surprised to read kaste spec that the 42 fly used less than ips as its a much heavier boat with more wind resistance.

As with anything that hangs in the water thats mechanical its going to take a battering at some point in its life, unlike a pair of shafts, props, rudders etc which will hang around for years as long as the anodes keep doing there job.

I was discussing with a forum memeber last week after I had just serviced his D6 motors, the balance of cost paying to service 2 engines then 2 drives over a seasons boating around the solent wont stack up as being cheaper to run than a shaft boat of say 42ft.

Then there are the issues later on in life, a nice shaft installation will be far easier to work on and be protected better than an ageing sterndrive package which will suffer problems with trim pumps, hoses, steering pipes, rams and exhaust risers which to repair wil mean engines out and a hefty labour bill in future years to make serviceable again, where a shaft drive boat, the motors wil sit there for years with just regular servicing and some tlc.

All things that need to be taken seriously when buying a boat, look at how many hours you do a year, where you boat, what type of boat suits you and of course how deeps your pocket! by getting that right you can shave off a few pounds each season.

 

[gjgm]

I am surprised to read kaste spec that the 42 fly used less than ips as its a much heavier boat with more wind resistance.

As with anything that hangs in the water thats mechanical its going to take a battering at some point in its life, unlike a pair of shafts, props, rudders etc which will hang around for years as long as the anodes keep doing there job.

I was discussing with a forum memeber last week after I had just serviced his D6 motors, the balance of cost paying to service 2 engines then 2 drives over a seasons boating around the solent wont stack up as being cheaper to run than a shaft boat of say 42ft.

Then there are the issues later on in life, a nice shaft installation will be far easier to work on and be protected better than an ageing sterndrive package which will suffer problems with trim pumps, hoses, steering pipes, rams and exhaust risers which to repair wil mean engines out and a hefty labour bill in future years to make serviceable again, where a shaft drive boat, the motors wil sit there for years with just regular servicing and some tlc.

All things that need to be taken seriously when buying a boat, look at how many hours you do a year, where you boat, what type of boat suits you and of course how deeps your pocket! by getting that right you can shave off a few pounds each season.

Cant remember which manufacturer said this (maybe many) but " we only sell the boat once". Actually, that was to do with internal design fashion, and why they had to follow client demands an expectations.
Anyway, my point is that not many new owners keep a o/drive driven boat all the way through to the point major repairs are due. How old is a well maintained boat before those problems arise , do you feel? And by that point, its probably another owner's problems, and that is reflected in the price (of say a ten year old boat).
Interesting question though, as to overall price difference over, say ,first five years of ownership.

 

[volvopaul]

Cant remember which manufacturer said this (maybe many) but " we only sell the boat once". Actually, that was to do with internal design fashion, and why they had to follow client demands an expectations.
Anyway, my point is that not many new owners keep a o/drive driven boat all the way through to the point major repairs are due. How old is a well maintained boat before those problems arise , do you feel? And by that point, its probably another owner's problems, and that is reflected in the price (of say a ten year old boat).
Interesting question though, as to overall price difference over, say ,first five years of ownership.

Very good question, it really depends on what make of engines you have.

Say a 15 year old Fline targa with a pair of kad42s your looking at new exhaust risers, trim rams, hoses etc so thats engine out time and many bucks, if your selling and the new buyer gets me along for a survey these are the issues I always point out with an older stern drive boat, so net result is the buyer knocks 15k off the price to cover it.

Thats really where it is, wether its another owners problem and thats probably what your thinking about as your on drives the problem never goes away, you either sell at a loss or pay for it youself, id say first 5 years is ok, its between 5 and 10 when you start to get major problems.

What I can say about the newer D 4 and 6 range is, I dont think they will last as long as the older generation engines and drives before now ive had to replace steering, rams, hoses and trim hoses on boats younger than 3 years, nothing has been modified in terms of evolution towards extra reliabilty and longevity so the cycle will return to bite whichever owner the boat has.

Saying all that id love a V45!

 

[Deleted User YDKXO]

Cant remember which manufacturer said this (maybe many) but " we only sell the boat once".

I'm not sure any manufacturer would be that shortsighted and in any case it's wrong. The ability of a manufacturer to sell a new boat depends to some extent on how easy or difficult the prospective first owner thinks it will be to sell the boat on and how much depreciation he will incur. I guess very few new boat buyers give no consideration at all to the resale issue. Then of course the second buyer of the boat has similar concerns and the third and so on. So a manufacturer has to ensure that his boats are popular on the used market because it's the used market which supports the new market. So if a manufacturer finds that his IPS boats are bombing on the used market, you can be sure that he will try to do something about it with dropping IPS altogether being one of the options. Anyway the dealers will soon start complaining to the manufacturer because they're the ones stuck with the IPS trade ins and certainly, if they cant move trade ins along, they cant sell new boats

 

[kashurst]

I did a bit of a spreadsheet calculation using the figures Galps posted (thank you). At an average of 23Kn for 100 hours a year the fuel saving is @ £500 at £1 a litre. This is negated by the extra maintenance. At an average of 29 Kns for 100 hours the savings are about £5K !!

It seems to me that if you use your boat every day or certainly every weekend and go fast all the time and do more than say 200 hours a year, then IPS is definitely worth it. So professional skippers then.

If however your usage is summer months and mixed speeds you would probably be better off with shafts/outdrives - the extra spent on fuel would be less than the extra maintenance.

 

[Deleted User YDKXO]

I've seen the figures now and I guess you're referring to the MBM test? Yes they are interesting but it does state that Sealine are hoping to improve the fuel efficiency of the F42 by tweaking the props. You could also argue that the F42 is a larger boat as it has a foot extra in the beam which will show in extra accomodation space but overall, I am surprised by how close the test mpg figures are

 

[Deleted User YDKXO]

I did a bit of a spreadsheet calculation using the figures Galps posted (thank you). At an average of 23Kn for 100 hours a year the fuel saving is @ £500 at £1 a litre. This is negated by the extra maintenance. At an average of 29 Kns for 100 hours the savings are about £5K !!

It seems to me that if you use your boat every day or certainly every weekend and go fast all the time and do more than say 200 hours a year, then IPS is definitely worth it. So professional skippers then.

If however your usage is summer months and mixed speeds you would probably be better off with shafts/outdrives - the extra spent on fuel would be less than the extra maintenance.

Interesting figures and they seem to illustrate one advantage of IPS in that IPS seems to be more efficient than shafts at higher speeds. I suppose this sort of makes sense as IPS pods are designed to be hydrodynamically efficient and this advantage over shaftdrive will show up more at higher speeds. But the question is whether the hull is capable of running at those higher speeds in anything other than flat calm. I suspect that in the case of the F42, you wont be able to bomb along at 29knots on most passages unless you've got an onboard chiropractor so whether the £5k pa saving can be realised in practice is doubtful