Axiom Props

[Gibbo]

Remember the resounding slagging off and accusations of "snake oil" that the new Axiom propellor got on here from loads of people who'd never seen or tried one?

 

Anyone seen the test results in the May issue of Yatching Monthly? It came in rather well. They thought it was quite good overall. In fact, very good. Apparently the reverse power was extremely good. It got 3rd position out of about 12 on this point (IIRC - I was in the waiting room at hozzie whilst reading it so didn't get chance for a full read).

 

Gibbo

[WotEver]

Remember the resounding slagging off and accusations of "snake oil" that the new Axiom propellor got on here from loads of people who'd never seen or tried one?

 

Anyone seen the test results in the May issue of Yatching Monthly? It came in rather well. They thought it was quite good overall. In fact, very good. Apparently the reverse power was extremely good. It got 3rd position out of about 12 on this point (IIRC - I was in the waiting room at hozzie whilst reading it so didn't get chance for a full read).

 

Gibbo

 

It's also in this month's issue of Waterways World (or canal Boat, I bought both yesterday) - I was reading it only last night. Similar conclusions. Also, considerably less wake as it didn't make the stern 'squat' as much.

 

Regards,

Tony

Edited June 15, 2009 by tony@hdheaven.co.uk

[Mac of Cygnet]

Saw a guy fitting one to his boat at Bill Fen last week. He promised to post his impressions here when he was back in the water (including how it copes with the increasing amount of blanket weed in the area)

[WotEver]

(including how it copes with the increasing amount of blanket weed in the area)

 

He's boating in my pond?

 

T

[churchward]

I saw the article in the WW but not the Yacht one. The WW article was interesting as it used two near identical boats from a hire fleet and compared conventional and Axiom props. It all sounded very good as it said in the article I suppose it depends if you can justify the extra expense of the Axiom type.

 

I still don't really understand how it can create less wash but I know next to nothing about such things.

Edited June 15, 2009 by churchward

[RLWP]

I still don't really understand how it can create less wash but I know next to nothing about such things.

 

This is the aspect I would like explained as well. How does a different prop make less bow wave?

 

Richard

[PaulG]

Remember the resounding slagging off and accusations of "snake oil" that the new Axiom propellor got on here from loads of people who'd never seen or tried one?

 

Anyone seen the test results in the May issue of Yatching Monthly? It came in rather well. They thought it was quite good overall. In fact, very good. Apparently the reverse power was extremely good. It got 3rd position out of about 12 on this point (IIRC - I was in the waiting room at hozzie whilst reading it so didn't get chance for a full read).

 

Gibbo

 

Yup, I was one of the ones who was slagging it off. Mainly because of the total lack of any authoritative independent evidence to back up their claims - a bit like the "University of St. Andrews" scenario, Gibbo

 

I'll try and find the article and read it while the missus warms up the humble pie...

[WotEver]

This is the aspect I would like explained as well. How does a different prop make less bow wave?

 

Richard

 

Hi Richard,

 

The explanation in WW and also on Axiom's website states that the boat squats less at the stern, hence the bow sits lower and the whole boat stays more level which in turn will create less bow wave.

 

I don't know why a 'flatter' sitting hull should create less wave either, I'm just repeating what's documented.

 

Regards,

Tony

[PaddingtonBear]

What extra expense? they must be seriously dear if they are dearer than Crowthers unless snake oil does work after all - is that 30 CC Api BTW

[RLWP]

Hi Richard,

 

The explanation in WW and also on Axiom's website states that the boat squats less at the stern, hence the bow sits lower and the whole boat stays more level which in turn will create less bow wave.

 

I don't know why a 'flatter' sitting hull should create less wave either, I'm just repeating what's documented.

 

Regards,

Tony

 

OK, so how does this prop cause less squat at the stern?

 

Richard

 

I'm not really asking you, I'm waiting for someone to come up with some creditable, independant information.

[WotEver]

OK, so how does this prop cause less squat at the stern?

 

Actually, if I remember correctly, WW did explain that. The Axiom prop gives a 'cleaner' 'straight' thrust out the back with less downforce than a conventional prop.

 

No idea why, so maybe I should just shut up

 

Edited to say that Axiom's site gives this explanation: "The marine screw moves a vast amount of water but this does not necessarily mean thrust. Instead you may experience slump – the stern digs in and the bow rises. You may also notice a “twist” in the propeller wake". So I guess what they're saying is that if you're moving a lot of water away from the stern (although not necessarily in a rearwards direction) the stern will slump down into the 'hole' you just made.

Edited June 15, 2009 by tony@hdheaven.co.uk

[kbarber]

Hmm interesting. We were out this weekend and for some reason the bow seemed lower in the water than usual (yes, we did check for water where it shouldn't be). And we found we seemed to be able to go faster than usual too. So if the Axiom thingy does keep the bow lower, they may have a point. (And of course a bit more ballast in the sharp end might have the same effect.)

 

Of course this has no scientific validity whatsoever, in the absence of a proper explanation

 

K

[Chris G]

What extra expense? they must be seriously dear if they are dearer than Crowthers unless snake oil does work after all - is that 30 CC Api BTW

 

Ah! but were they comparing the Axiom with a correctly propped boat, let alone one with a Crowther prop!

[rjasmith]

Ah! but were they comparing the Axiom with a correctly propped boat, let alone one with a Crowther prop!

 

Having got quotes from both companies recently I can say that Crowthers are really quite reasonable in comparison!

 

I'm still thinking about it!!!

 

Richard

[Greybeard]

Hi

 

I don't know how much a Crowthers 14" prop would be but I've been quoted £690.00 for an Axiom 3 bladed version.

 

Price includes for delivery but not VAT (they're not registered)

 

Boat not out of water until next Spring so I've a little time for more homework (given that there price doesn't increase in the meantime).

 

I've actually got to check the diameter as I'm not sure what size prop I need so started at 14" for a guide price.

 

GB

[Tony Brooks]

Ah! but were they comparing the Axiom with a correctly propped boat, let alone one with a Crowther prop!

 

 

In February I changed the original turbine screw for a large blade area Crowthers job and I had already gone to some lengths to assess the size required. It so happens Crowthers recommended the same.

 

Having tried the boat what did I find and I admit this has no scientific validity.

 

Less prop wash except on shallow sections.

Less wake

The ability to pass moored boats faster WITHOUT moving them about.

Seemingly less stressed engine sound.

Less prop walk in reverse

Easier steering

I get the impression the Bukh now produces less smoke at low speed but goodness knows why.

 

BUT:

 

I now need about 100 to 200 rpm more to achieve the same speed.

 

I asked my so for his impressions of the new prop and he seems to have come to similar conclusions.

 

 

Now I also had a longish talk with Mr Axiom at Crick hoping to get a scientific explanation for their claims but unfortunately either he did not know or felt showing me graphs and magazine articles was more appropriate. He also started off by talking about air propellers. I did let him know what I do but it made little difference to his spiel.

 

Unfortunately until someone explains in scientific terms how the thing achieves what they claim I think we should treat the claims with a degree of scepticism. It would also be good to see some independent corroboration of the claims from a well thought of research institute.

 

I know what WW found, but I still wonder about the boats being correctly propped. It is not unknown for hire fleets to under-prop their boats.

[Gibbo]

But.........

 

Yachting Monthly tested it and said it was great.

 

Why still the negativity?

 

It reminds me of when we introduced a certain one of our devices. A lot of the armchair experts who didn't understand how it worked concluded that it couldn't work, simply because they didn't know how it worked! That's quite a stupid basis upon which to form a conclusion. Do the same people refuse to buy a TV? Don't pretend you all know how one works because you don't!

 

Yachting Monthly have concluded that it works well in quite a comprehensive test. Yet now what I hear is "Well maybe all the others weren't propped up correctly"!!!!! Come on, accept that you might have been wrong and it does actually work!

 

I'm convinced enough following the YM test and I'm putting one on Lionheart. If only because Crowthers couldn't be bothered replying to my second email.

 

</rant>

 

Gibbo

[carlt]

They thought it was quite good overall. In fact, very good. Apparently the reverse power was extremely good. It got 3rd position out of about 12 on this point

So it's quite good overall and third best, for reversing.

 

Were the two that beat it revolutionary new props or just good versions of a tried and trusted design?

 

If it is as good as they say, then surely it should reverse better than any conventional prop and perform better, overall, than "quite goos".

[Tony Brooks]

But.........

 

Yachting Monthly tested it and said it was great.

 

Why still the negativity?

 

It reminds me of when we introduced a certain one of our devices. A lot of the armchair experts who didn't understand how it worked concluded that it couldn't work, simply because they didn't know how it worked! That's quite a stupid basis upon which to form a conclusion. Do the same people refuse to buy a TV? Don't pretend you all know how one works because you don't!

 

Yachting Monthly have concluded that it works well in quite a comprehensive test. Yet now what I hear is "Well maybe all the others weren't propped up correctly"!!!!! Come on, accept that you might have been wrong and it does actually work!

 

I'm convinced enough following the YM test and I'm putting one on Lionheart. If only because Crowthers couldn't be bothered replying to my second email.

 

</rant>

 

 

Gibbo

 

 

I am far from saying that it does not work, but I am saying is that there might (not are) be other explanations for the apparent benefits and unless the vendor can show some scientific evidence for their assertions one would do well to keep an open mind.

 

I think potential customers who want to know how it works should be given that information.

 

I am afraid that until I can be convinced that the extra cost of about £350 over the Crowther prop will be money well spent I remain sceptical.

 

I have had the operation of a TV explained in enough detail to convince me that I know enough to conclude it probably works as claimed. I know enough about a variety of battery monitoring and testing equipment to conclude that your product works as claimed and , more to the point, you engaged in some fairly technical discussions about it even if you were understandably unwilling to tell us everything.

 

I just do not understand why we can not have the way the prop achieves what is claimed explained to us. I may not, probably will not, I can understand all of it but with the informed comment from other members of the forum I can then make a decision about it.

[Guest]

Sorry but the test of two identcal boats is flawed. More crap on the bottom? Different ballast? Different fuel/water loads? No of hours on engine? Was the original one propped correctly? All the other differences i haven't thought of yet?

 

Nowhere near a proper test. It would require the same boat repropping with various conventional props, followed by the Axiom one.

Edited June 15, 2009 by Guest

[churchward]

Sorry but the test of two identcal boats is flawed. More crap on the bottom? Different ballast? Different fuel/water loads? No of hours on engine? Was the original one propped correctly? All the other differences i haven't thought of yet?

 

Nowhere near a proper test. It would require the same boat repropping with various conventional props, followed by the Axiom one.

I agree it is not a competely scientific test but it is the closest we have seen to date in that the boats are of the same design and age. I don't know this for a fact but I assume they were picked because they performed similarly in the first place so changing the prop on one would demonstrate a difference logically.

 

I am not saying you have to believe the Axiom sales pitch (there is much I don't understand) but I think there is enough here to take a view that something different is happening with the Axiom prop and it seems to be a good difference. So, either way it is useful to keep an open mind.

 

As for conditions like "more crap on the bottom" well when you get down to that level of objection nothing short of a sterile canal in a laboratory is going to do is it and then I can here someone banging on about chaos theory or such-like.

 

There is however the fact that it is chuffing expensive and I would have to be really sure it was worth it to cough up the difference personally.

 

I am far from saying that it does not work, but I am saying is that there might (not are) be other explanations for the apparent benefits and unless the vendor can show some scientific evidence for their assertions one would do well to keep an open mind.

 

I think potential customers who want to know how it works should be given that information.

 

I am afraid that until I can be convinced that the extra cost of about £350 over the Crowther prop will be money well spent I remain sceptical.

 

I have had the operation of a TV explained in enough detail to convince me that I know enough to conclude it probably works as claimed. I know enough about a variety of battery monitoring and testing equipment to conclude that your product works as claimed and , more to the point, you engaged in some fairly technical discussions about it even if you were understandably unwilling to tell us everything.

 

I just do not understand why we can not have the way the prop achieves what is claimed explained to us. I may not, probably will not, I can understand all of it but with the informed comment from other members of the forum I can then make a decision about it.

As I say above Tony I agree an open mind is best in both directions so you also need to recognise the possibility that such a design could be producing the claimed results.

 

I find the talk of "scientific evidence" slightly bizarre as even if we had all the necessary data to hand most will probably not understand it so like your Crowther prop that you seem to be able to take on a non-scientific basis as an improvement we have to go buy weight of argument and some demonstration.

 

For my part with the number of articles now and trials that are showing at least reasonable anecdotal evidence of a benefit I have to conclude that something in this new design has merit. Whether this has more merit than a good conventional prop (like the Crowthers) matched to the boat and engine/gearbox combination is another matter as is the price.

Edited June 15, 2009 by churchward

[alan_fincher]

There is however the fact that it is chuffing expensive and I would have to be really sure it was worth it to cough up the difference personally.

I'd also want to know it was as durable as a conventional narrow boat prop.

 

Obviously one can't judge blade thickness from those small published pictures, but the squared off ends look somehow more vulnerable than the conventional approach.

 

An awful lot of narrowboat propellors get wrecked, sometimes terminally - if these things are as "chuffing expensive" as all that, it would be sad to make the investment, only to have it bend soon after.

[starman]

At £700 a pop maybe the most important scientific test would be how well it survives running over a supermarket trolley...

[churchward]

I'd also want to know it was as durable as a conventional narrow boat prop.

 

Obviously one can't judge blade thickness from those small published pictures, but the squared off ends look somehow more vulnerable than the conventional approach.

 

An awful lot of narrowboat propellors get wrecked, sometimes terminally - if these things are as "chuffing expensive" as all that, it would be sad to make the investment, only to have it bend soon after.

I agree no good if the corners get knocked of it the first time it hits something solid or soon after and the corners were the important bit in the design. I did have a nose around one at the Axiom stand at Crick it did look every bit as solid made as a normal prop but I share your thoughts on that.

[Gibbo]

So it's quite good overall and third best, for reversing.

 

Were the two that beat it revolutionary new props or just good versions of a tried and trusted design?

 

If it is as good as they say, then surely it should reverse better than any conventional prop and perform better, overall, than "quite goos".

 

IIRC the two that beat it in reverse weren't as good going pointy end first.

 

I'm not sayng it does work or that it's brilliant. What I'm saying is this whole notion of "It can't work because I don't understand how" is nothing short of retarded.

 

But, as I said, I'm putting one on my boat.

 

Gibbo