Andrew_Fanner
Well-Known Member
But has Yellowfin died a death? That still looks like a good option because of the possibilities of retrofit to shaft drive boats.
IPS and other drive options
- Thread starter TigaWave
- Start date
rickp
Well-Known Member
I thought the Yellowfin folks had signed up with an engine manufacturer and weren't looking at retro-fit. Its all gone very quiet though, which can't be good news.
Rick
Rick
Major Catastrophe
Well-Known Member
[ QUOTE ]
But has Yellowfin died a death? That still looks like a good option because of the possibilities of retrofit to shaft drive boats.
[/ QUOTE ]
Can it? I understood Yellowfin came out through the transom as in the photo below, so there would have to be a fair amount glass work.
But has Yellowfin died a death? That still looks like a good option because of the possibilities of retrofit to shaft drive boats.
[/ QUOTE ]
Can it? I understood Yellowfin came out through the transom as in the photo below, so there would have to be a fair amount glass work.
PowerYachtBlog
Well-Known Member
[ QUOTE ]
The Zeus system is still going but only available in very limited numbers, I think there maybe a few issues with the system so it takes a long time to produce and set up.
There was an IPS/Zeus shootout on Boattest.com using a pair of Dorals but I cannot get the website to work to provide a link!! I also heard snippets from the unofficial report by the engineers on the test and in general IPS was a fair way ahead of Zeus.
[/ QUOTE ]
while this is true it is not easy as you say it
it is impossible to try the same boat with different POD drive and you get results which would not prefare a builder from another
both of the pod have different variation modification needs to a hull design which can make an outcome of a design go the other
IPS need a flat vee aft genereally and the Zeus need the pocket
so far but dont quote me to the full here, Zeus has been retrofitted, that means no hull has been specifically designed for it, this is soon to be solved as new GrandBanks 44 is designed around Zeus but is a Semi-Planning design
on the other hand IPS has varous boats built around it
like new Abs 47 and 52, Farline 44 TarGT, Atlantis 50, Astonda 44 Muse etc etc
IPS needs more deadrise modification aft and Zeus usually only pockets, some say it is less expensive for builders to go for Zeus
while the marketing geniouses at Volvo claim improved fuel economy from 20% to 40% later data is that if hull is designed around, this report shows that best economy was achieved with the Yanmar 480s at about 23 knots, standard shaft drive Boattest fuel comparison
The Zeus system is still going but only available in very limited numbers, I think there maybe a few issues with the system so it takes a long time to produce and set up.
There was an IPS/Zeus shootout on Boattest.com using a pair of Dorals but I cannot get the website to work to provide a link!! I also heard snippets from the unofficial report by the engineers on the test and in general IPS was a fair way ahead of Zeus.
[/ QUOTE ]
while this is true it is not easy as you say it
it is impossible to try the same boat with different POD drive and you get results which would not prefare a builder from another
both of the pod have different variation modification needs to a hull design which can make an outcome of a design go the other
IPS need a flat vee aft genereally and the Zeus need the pocket
so far but dont quote me to the full here, Zeus has been retrofitted, that means no hull has been specifically designed for it, this is soon to be solved as new GrandBanks 44 is designed around Zeus but is a Semi-Planning design
on the other hand IPS has varous boats built around it
like new Abs 47 and 52, Farline 44 TarGT, Atlantis 50, Astonda 44 Muse etc etc
IPS needs more deadrise modification aft and Zeus usually only pockets, some say it is less expensive for builders to go for Zeus
while the marketing geniouses at Volvo claim improved fuel economy from 20% to 40% later data is that if hull is designed around, this report shows that best economy was achieved with the Yanmar 480s at about 23 knots, standard shaft drive Boattest fuel comparison
Major Catastrophe
Well-Known Member
[ QUOTE ]
I thought the Yellowfin folks had signed up with an engine manufacturer and weren't looking at retro-fit. Its all gone very quiet though, which can't be good news.
Rick
[/ QUOTE ]
VW if I remember correctly, but I was under the impression that was for OEM build.
I thought the Yellowfin folks had signed up with an engine manufacturer and weren't looking at retro-fit. Its all gone very quiet though, which can't be good news.
Rick
[/ QUOTE ]
VW if I remember correctly, but I was under the impression that was for OEM build.
TigaWave
Well-Known Member
Thats how I understood it, it could retro fit stern drives I thought?
Seatorque is the only retro fit for shaft set ups with little or no modification to the hull, I'll post the test results here soon on the viking 64. It's been run with conventional shafts to get baselines for noise performance vibration, re fitting with seatorque should only be a day or twos work.
Seatorque is the only retro fit for shaft set ups with little or no modification to the hull, I'll post the test results here soon on the viking 64. It's been run with conventional shafts to get baselines for noise performance vibration, re fitting with seatorque should only be a day or twos work.
Andrew_Fanner
Well-Known Member
[ QUOTE ]
[ QUOTE ]
But has Yellowfin died a death? That still looks like a good option because of the possibilities of retrofit to shaft drive boats.
[/ QUOTE ]
Can it? I understood Yellowfin came out through the transom as in the photo below, so there would have to be a fair amount glass work.
[/ QUOTE ]
May be my misinterpretation then, ISTR the original articles mentioned that a shaftdrive conversion was an intended feature, perhaps by putting it in a casing under the hull?
[ QUOTE ]
But has Yellowfin died a death? That still looks like a good option because of the possibilities of retrofit to shaft drive boats.
[/ QUOTE ]
Can it? I understood Yellowfin came out through the transom as in the photo below, so there would have to be a fair amount glass work.
[/ QUOTE ]
May be my misinterpretation then, ISTR the original articles mentioned that a shaftdrive conversion was an intended feature, perhaps by putting it in a casing under the hull?
D
Deleted User YDKXO
Guest
TigaWave, despite my comments of yesterday, I'm very interested because if you can prove that the Seatorque systems really delivers an 8% improvement in 'performance' (you still have'nt defined that btw), then, depending on the cost of the system, you could be on to a winner
On that subject, what would be an approx cost for supplying and fitting a system to, say, a typical twin engine 46 footer?
On that subject, what would be an approx cost for supplying and fitting a system to, say, a typical twin engine 46 footer?
Major Catastrophe
Well-Known Member
[ QUOTE ]
May be my misinterpretation then, ISTR the original articles mentioned that a shaftdrive conversion was an intended feature, perhaps by putting it in a casing under the hull?
[/ QUOTE ] Not sure about that, but as it is a Variable Surface Drive, i think it must be somewhere near the surface to work.
But, as the media hype on Yellowfin has subsided, they have either been quietly working on it, or it doesn't work.
May be my misinterpretation then, ISTR the original articles mentioned that a shaftdrive conversion was an intended feature, perhaps by putting it in a casing under the hull?
[/ QUOTE ] Not sure about that, but as it is a Variable Surface Drive, i think it must be somewhere near the surface to work.
But, as the media hype on Yellowfin has subsided, they have either been quietly working on it, or it doesn't work.
TigaWave
Well-Known Member
On a 48 we have just quoted with twin 600hp and 2.3m shaft length cost was around $13,000 per shaft ex factory.
There are a few options like rope cutters, onodizing colour and temperature guages.
No cutless bearing, no stuffing box or stern seal, the unit comes complete with oil system, tank and cardan shaft coupling. Ready to be slid in and bolted to the bulkhead.
There are a few options like rope cutters, onodizing colour and temperature guages.
No cutless bearing, no stuffing box or stern seal, the unit comes complete with oil system, tank and cardan shaft coupling. Ready to be slid in and bolted to the bulkhead.
Whitelighter
Well-Known Member
Seems like you will have to go through a lot of fuel to recoup the cost.
Or are there other benefits I am missing? Is some of the cost offset by not having the items you would normally have on a shaft drive boat?
Or are there other benefits I am missing? Is some of the cost offset by not having the items you would normally have on a shaft drive boat?
D
Deleted User YDKXO
Guest
Wow, thats a lot of money. So call it £20k Sterling for both shafts including transport to UK, VAT and fitting.
Say the boat is going to do 1500nm per season @ 0.7mpg, thats £10714 worth of fuel per season @ £5 per gallon. You say that the system gives an 8% improvement in 'performance'. Lets say that means an 8% fuel saving which is £857 per season saving. If the system costs £20k fitted, that means a 23 year payback period which is not exactly attractive
Feel free to argue with my figures but it looks like the system is not worthwile for pleasure boaters unless there are other savings which I have'nt taken account of. Of course, for commercial users with much higher usage, the calculation could be very different
Say the boat is going to do 1500nm per season @ 0.7mpg, thats £10714 worth of fuel per season @ £5 per gallon. You say that the system gives an 8% improvement in 'performance'. Lets say that means an 8% fuel saving which is £857 per season saving. If the system costs £20k fitted, that means a 23 year payback period which is not exactly attractive
Feel free to argue with my figures but it looks like the system is not worthwile for pleasure boaters unless there are other savings which I have'nt taken account of. Of course, for commercial users with much higher usage, the calculation could be very different
MapisM
Well-Known Member
[ QUOTE ]
you still have'nt defined that btw
[/ QUOTE ]Actually the site gives some further details about that:
"Up to 8% in performance gains can be achieved over a conventional shaft set up"
Whereas by conventional shaft they apparently mean a:
"traditional rubber bearing supported shaft system where thrust is taken on the engine mounts"
Besides, they state that:
"The system has mechanical losses of 2% and eliminates the need for cutless bearings stern glands stuffing boxes or dripless seals and the associated plumbing."
As a consequence, I would assume that the 8% "gain" is actually a reduction of power losses in transmission from a conventional system - supposed to loose 10% - to just 2%.
In other words, I'm afraid that the punter of your previous example, who...
[ QUOTE ]
could assume that fitting this system would turn his 30.0kt boat into a 32.4kt boat
[/ QUOTE ]would actually be wrong.
What the punter could expect is, if his boat has a conventional shaft with stuffing boxes, where currently 100hp are delivered to the gearbox and 90 are left to the prop, is to get back 8 of those 10hp 'lost in transmission', having therefore 98hp at the prop. What this means in terms of speed, that depends of course also on other factors.
All the above in my understanding of course - TigaWave can surely confirm or correct.
On the other hand, there are some points for which I didn't find comments/explanations on that site:
1) adapting a boat built for thrust beared by the engines may require hull reinforcements/adaptations to use such system;
2) out of the 8% reduction of power losses, it is not mentioned how much is due respectively to the elimination of stuffing boxes vs. the shaft outer casing. I suspect that the first accounts for more than the latter, and I don't see how a shaft casing can be seen as a simpler installation anyhow;
3) the idea of having a thrust bearing housing and a cardan shaft to the engine to eliminate alignment issues is not exactly new. My boat is built like that, in spite of the fact that being a wooden trawler she's not exactly at the forefront of naval engineering innovation. Aquadrive is just one example of a tried and tested similar system (though it doesn't use a shaft casing).
you still have'nt defined that btw
[/ QUOTE ]Actually the site gives some further details about that:
"Up to 8% in performance gains can be achieved over a conventional shaft set up"
Whereas by conventional shaft they apparently mean a:
"traditional rubber bearing supported shaft system where thrust is taken on the engine mounts"
Besides, they state that:
"The system has mechanical losses of 2% and eliminates the need for cutless bearings stern glands stuffing boxes or dripless seals and the associated plumbing."
As a consequence, I would assume that the 8% "gain" is actually a reduction of power losses in transmission from a conventional system - supposed to loose 10% - to just 2%.
In other words, I'm afraid that the punter of your previous example, who...
[ QUOTE ]
could assume that fitting this system would turn his 30.0kt boat into a 32.4kt boat
[/ QUOTE ]would actually be wrong.
What the punter could expect is, if his boat has a conventional shaft with stuffing boxes, where currently 100hp are delivered to the gearbox and 90 are left to the prop, is to get back 8 of those 10hp 'lost in transmission', having therefore 98hp at the prop. What this means in terms of speed, that depends of course also on other factors.
All the above in my understanding of course - TigaWave can surely confirm or correct.
On the other hand, there are some points for which I didn't find comments/explanations on that site:
1) adapting a boat built for thrust beared by the engines may require hull reinforcements/adaptations to use such system;
2) out of the 8% reduction of power losses, it is not mentioned how much is due respectively to the elimination of stuffing boxes vs. the shaft outer casing. I suspect that the first accounts for more than the latter, and I don't see how a shaft casing can be seen as a simpler installation anyhow;
3) the idea of having a thrust bearing housing and a cardan shaft to the engine to eliminate alignment issues is not exactly new. My boat is built like that, in spite of the fact that being a wooden trawler she's not exactly at the forefront of naval engineering innovation. Aquadrive is just one example of a tried and tested similar system (though it doesn't use a shaft casing).
D
Deleted User YDKXO
Guest
All good points. My point in asking whether this system would turn a 30kt boat into a 32.4kt was really to encourage TigaWave to give us more information as to what this statement of an 8% increase in performance actually means. I guess you are right and it means an 8% increase in power transmitted to the prop which, as you say, does not necessarily mean an 8% increase in speed or an 8% decrease in fuel consumption
codprawn
Member
My main worry about IPS is what would happen if you hit something? I have asked this before and had no logical answers.
With an outboard or outdrive the leg will kick up if you hit something and the skeg protects the prop. With shaft drives the hull protects the props - especially if they are in tunnels.
IPS looks so vulnerable. It is not only prop damage you have to worry about but hull damage as well. Yes I know they are supposed to break away in an accident BUT how often do things like this work in real life?
Jet engines on aircraft are meant to break away during a crash landing but most don't - some have on takeoff though!!!
With an outboard or outdrive the leg will kick up if you hit something and the skeg protects the prop. With shaft drives the hull protects the props - especially if they are in tunnels.
IPS looks so vulnerable. It is not only prop damage you have to worry about but hull damage as well. Yes I know they are supposed to break away in an accident BUT how often do things like this work in real life?
Jet engines on aircraft are meant to break away during a crash landing but most don't - some have on takeoff though!!!
Nick_H
Well-Known Member
The hull/keel doesn't protect the props on shaft drive planing boats, which is where IPS is really aimed, in fact they're every bit as exposed as the props on IPS if there's no tunnels, and only slightly less if there is. At least IPS is designed to shear off and leave the hull watertight in the event of an impact, so the only worry is whether that design feature will fail. Shaft drive boats aren't even designed to withstand an impact, so you would have the near certainty of major damage, water ingress and possible sinking if you ran in to something solid at speed
TigaWave
Well-Known Member
The techniques and components are not new as someone else said.
The cost saving really comes in at the factory build stage, as there is a huge labour and time saving in construction.
Actual cost benefits for retro fit units are more difficult to equate, as you have calculated these don't sell on a performance cost saving alone! But when you add up the lack of vibration and noise as well as the reduced long term maintenance issues of bearing and shaft replacements it makes more sense.
But you are all right so far, its not that clever its just a well built complete one piece drive unit that bolts in quickly and simply. The performance gains are an added benefit.
Simplicity is in terms of still being a direct drive to props with seperate systems for steering.
It suits prodution line boat building and gives performance benefits, after all the engine shaft seperate rudder is proven and many boats are designed around this set up.
We will have more details soon on the performance and testing with Viking so watch this space.
The cost saving really comes in at the factory build stage, as there is a huge labour and time saving in construction.
Actual cost benefits for retro fit units are more difficult to equate, as you have calculated these don't sell on a performance cost saving alone! But when you add up the lack of vibration and noise as well as the reduced long term maintenance issues of bearing and shaft replacements it makes more sense.
But you are all right so far, its not that clever its just a well built complete one piece drive unit that bolts in quickly and simply. The performance gains are an added benefit.
Simplicity is in terms of still being a direct drive to props with seperate systems for steering.
It suits prodution line boat building and gives performance benefits, after all the engine shaft seperate rudder is proven and many boats are designed around this set up.
We will have more details soon on the performance and testing with Viking so watch this space.
codprawn
Member
Unless you are driving at high speed astern I disagree. The shafts are angled so they will tend to slide over rocks rather than dig in. also even without tunnels many boats have a small skeg on the keel which will give some protection. Some can even dry out!
The way the IPS drives just stick out like a sore thumb has to be asking for trouble.
A Nordhavn sank because a stabliser fin was ripped off and made a big hole. Sounds like a similar problem to me.
The way the IPS drives just stick out like a sore thumb has to be asking for trouble.
A Nordhavn sank because a stabliser fin was ripped off and made a big hole. Sounds like a similar problem to me.
MapisM
Well-Known Member
Believe me, you don't want to try "sliding over rocks" with any shaft boat, be it with or without tunnels.
Not that I'd recommend sliding over rocks with IPS, anyway.
Actually, I wouldn't recommend that with any boat.
The facts are:
1) IPS is designed for fast planing boats;
2) the most likely scenario which is bound to create major damages in such boats, is hitting a floating object at speed;
3) in that scenario, I tend to believe that a shaft boat wouldn't be better off than an IPS boat in terms of structural damages (considering also that no fast planing boat on earth have skegs protected props - let alone dry out capabilities).
On a side note, do you have any more details about the Nordhavn accident you're reporting?
Did the fin hit a floating object, or the boat went aground?
Not that I'd recommend sliding over rocks with IPS, anyway.
Actually, I wouldn't recommend that with any boat.
The facts are:
1) IPS is designed for fast planing boats;
2) the most likely scenario which is bound to create major damages in such boats, is hitting a floating object at speed;
3) in that scenario, I tend to believe that a shaft boat wouldn't be better off than an IPS boat in terms of structural damages (considering also that no fast planing boat on earth have skegs protected props - let alone dry out capabilities).
On a side note, do you have any more details about the Nordhavn accident you're reporting?
Did the fin hit a floating object, or the boat went aground?
codprawn
Member
I agree shafts are the worst case but compare IPS to normal sterndrives - any impact and you would be far better off with the sterndrives.
The Nordhavn accident was a real tradgedy - one man died as a result.
http://www.youtube.com/watch?v=BcQeH674BfU
The Nordhavn 62 hit an uncharted rock and tore off a fin - water was gushing in so they ran the boat ashore.
http://sancarlosmx.mywowbb.com/forum4/978-1.html
quite a suprise as they are my dream boat!!!
The Nordhavn accident was a real tradgedy - one man died as a result.
http://www.youtube.com/watch?v=BcQeH674BfU
The Nordhavn 62 hit an uncharted rock and tore off a fin - water was gushing in so they ran the boat ashore.
http://sancarlosmx.mywowbb.com/forum4/978-1.html
quite a suprise as they are my dream boat!!!