The Whirled At One.

[bizzard]

 

 

Point of order your Bizzardness...

 

Bubbles show the effect you descibe is aeration, not cavitation.

The bubbles yes. But by the roar that goes up, a bit of both I reckon. Know what I mean Arry. Props have been known to shatter in extreme cases, on ships too.

[wrigglefingers]

Evening ...

 

As you surmise, I am currently the available mod and I have been at work all day with very limited internet. I have taken down the previous thread because I need to read through the content. I will say this, however. You were asked, very clearly, not to discuss the specifics of the OP's post, but you continued. That meant that the entire thread has been hidden, because, with the best will in the world, I cannot weed through a thread with occasional internet on a 4" iPhone whilst I am at work.

 

I do understand that when you have contributed valuable and interesting content to a thread, it's frustrating for it to be taken down. I will go through this thread and the previous one to clean them up when I get home because I believe that, generally, there is some interesting content.

 

What you must not do is discuss or speculate on the original issue, nor must you refer to it, or start up any further threads. I would like your cooperation on this issue, otherwise I will discussing your actions with Daniel.

[bizzard]

I noticed while watching Red October that the nuclear submarines appear to use multi blade, 5 or 6 or maybe more like the Seagull motors, squarish profile prop blades too. Don't suppose Sean Connery knew that though.

[MtB]

Absolutely. If you are not allowed to return to the demerits of a technical product (discussed before at length) without the thread being taken down then what is the point.

Roger

Well there we have it.

 

Thread vanished not due to the discussion of the absense of technical merits of the product, but due to continuing discussing the details of the dispute despite a mod request to stop.

Edited September 26, 2016 by wrigglefingers

[Chewbacka]

They do look good but tuned for silence, as silence is more important than efficiency for a sneaky sub.

[bizzard]

The loss of my beautiful fans photo is the LIMIT.

[Cheshire cat]

I was down the weedhatch on Wednesday at BumbleHole. A local chap came along the towpath and enquired as to what I was up to. It turned out he was once a submariner.

 

He offered the information that clearing the prop on a submarine was a devil of a job and it was surprising what they sometimes picked up. I was dealing with fishing line and webbing at the time. Presumably he was thinking trawlers.

[wrigglefingers]

Morning folks,

 

I'm back at home after a five hour drive last night. Moderating content at a series of service stations was an interesting experience....

 

I've had to clean up this thread, which I've done. If some of your content has been lost, I will be messaging you. It isn't lost, merely hidden for admin purposes.

 

Second, I'm going to go through the previous thread, when I've fortified myself with a coffee, and see what I can restore. Bear with me.

 

The process of correctly propping a narrowboat is a fascinating one and I think would benefit from some explanation. As a historian, I'm afraid I tend to regard it as a black art, whereas I am sure that the mathematicians amongst you, could explain it all to me in equations, if only I had the wit to understand ...

 

I'm going to re-name this thread shortly too. Message me if you have any concerns and I'll try to help ...

Edited September 26, 2016 by wrigglefingers

[Dalslandia]

Sorry if I missunderstand, but the original topic was about the dispute between the OP and a company, and not the technical side of his problem. that problem need to be solved, the original posters second propeller have positive sides that was pointed out.

 

But we can talk eco fans, it start to get colder in here.

Edited September 26, 2016 by Dalslandia

[nicknorman]

Not sure how you can know as I do not believe you have ever had one on a boat of yours.

 

Axioms propellers are very good props and all the ones I have had and used have performed as they should have done, excellently.

We have a very good prop that performs as it should. However it is a conventional design? I think this is the point, alternative designs are not rubbish props but they are no better than a well made and matched conventional one, but seem very expensive.

 

We have seen various comparisons with positive and negative results, but I think the main problem is a lack of like for like comparisons. Typically someone will have a rubbish inappropriate prop that performs badly. They then change it for a well matched "alternative design" and are pleased with the results. What we don't know is what would have happened if they had instead changed the prop for a quality and well matched conventional one.

 

Ed: I've been asked to remove brand names in order not to get the forum into difficulty.

Edited September 26, 2016 by nicknorman

[wrigglefingers]

Dalslandia,

 

I have messaged you ...

[Athy]

 

 

I'm going to re-name this thread shortly too. ...

Wait until lunchtime and you can call it The Whirled At One.

[wrigglefingers]

Wait until lunchtime and you can call it The Whirled At One.

Excellent! Can I use that, Athy?

[Athy]

Excellent! Can I use that, Athy?

It'll cost ya...oh, seeing as it's you, go on then.

[wrigglefingers]

It'll cost ya...oh, seeing as it's you, go on then.

Thanks ❤️

[bizzard]

Personally I would slightly under prop an air cooled engine, likewise a water cooled engine if the cooling is thought or known to be less than adequate. Less chance of overheating, be able to go slower during tight maneuvers and alternator should charge a bit better.

[Geo]

The process of correctly propping a narrowboat is a fascinating one and I think would benefit from some explanation. As a historian, I'm afraid I tend to regard it as a black art, whereas I am sure that the mathematicians amongst you, could explain it all to me in equations, if only I had the wit to understand ...

.

 

Designing a good propeller for any boat needs a lot of good accurate information whether it is a marine or inland waterways boat. So many things can effect the need to create the pressure differences that cause a boat to move in the water. The wrong propeller on a boat can cause a boat to handle badly even dangerously in the wrong situation.

 

I have been able to test propellers on my boat from two makers both designed for the boat. To my surprise the most expensive one was not the best, rather the slightly cheaper one was better in all tests and regarding prop walk and reversing a lot better. So the design, form etc of a prop, can have different effects even when designed for a specific hull.

Edited September 26, 2016 by Geo

[Dalslandia]

Dalslandia,

 

I have messaged you ...

I know, Thank you,

You do a great job.

[Dalslandia]

About eco fans, I recently designed a propeller for a Long- Ez (it is an airplane) he had tested 6 propellers from 2 well respected propeller brands, but his best was still miss-matched, the new propeller that was calculated in my own made software. Increased the climb rate by 400 ft-min, from 600 to 1000 ft-min and top speed at altitude with 11 kts, increase from 170 to 181 kts

he got 3080 rpm with old prop, now he got the same rpm as I used as input 3250. so lets say he got 3250/3080=1,055 5.5% more power from the boxer.

to go 181 instead of 170 takes 20,7% more power, it can be engine power or propeller efficiency, it is called thrust power.

this means the new propeller is 20.7-5.5=15,2% more efficient, that is a eco(nomical) fan

 

what does this have to do with boats? well nothing and everything, the boat propeller work just the same as an air propeller, just a little more complicated with the cavitating, but is not effected of the speed of sound. the propellers sits in front or behind a body that screw up the flow, the same problem with correct in-data for the calculations

Edited September 26, 2016 by Dalslandia

[bizzard]

About eco fans, I recently designed a propeller for a Long- Ez (it is an airplane) he had tested 6 propellers from 2 well respected propeller brands, but his best was still miss-matched, the new propeller that was calculated in my own made software. Increased the climb rate by 400 ft-min, from 600 to 1000 ft-min and top speed at altitude with 11 kts, increase from 170 to 181 kts

he got before 3080 rpm now he got the same rpm I used as input 3250. so lets say he got 3250/3080=1,055 5.5% more power from the boxer.

to go 181 instead of 170 takes 20,7% more power, it can be engine power or thrust power.

this means the new propeller is 20.7-5.5=15,2% more efficient, that is a eco(nomical) fan

 

what does this have to do with boats? well nothing and everything, the boat propeller work just the same as an air propeller, just a little more complicated with the cavitating, but not effected of the speed of sound. the propellers sits in front or behind a body that screw up the flow, the same problem with correct in-data for the calculations

Have you noticed the Piaggio Avanti P180 aircraft. Executive jet size, but twin pusher turboprop Amazing, it seems to be able to cruise at almost the same speed as a pucker turbojet and almost as high, 37,000 ft or so.

[Dalslandia]

Wikie say long range cruise altitude is FL 410 (41000 ft) not bad

Have you noticed the Piaggio Avanti P180 aircraft. Executive jet size, but twin pusher turboprop Amazing, it seems to be able to cruise at almost the same speed as a pucker turbojet and almost as high, 37,000 ft or so.

[bizzard]

Wikie say long range cruise altitude is FL 410 (41000 ft) not bad

Yes, incredible for a propeller driven aircraft. I see them flying about on Flightradar24.

[wrigglefingers]

Bizzard ... This is to remind you ...

 

"My all metal 1950's LIMIT desk fan has the most beautiful and shapely blade form. When in motion they twinkle in the most charming and captivating manner. It bbbbblows like anything too."

[bizzard]

Bizzard ... This is to remind you ...

 

"My all metal 1950's LIMIT desk fan has the most beautiful and shapely blade form. When in motion they twinkle in the most charming and captivating manner. It bbbbblows like anything too."

OOOOH! my beauty, my beauty has returned, how wonderful, wonderful. Thank you Wriggles x

[wrigglefingers]

Quite simply, the pleasure is shared ❤️

Edited September 26, 2016 by wrigglefingers