Selecting a Prop

[willk]

Originally Posted by Steve509926

I'm sure it was your goodself willk who once said, "our village is big enough for more than one"

Poly I believe, different village

[beamishken]

Originally Posted by willk

Crikey. Remember the fella who dug up the local waste dump looking for his lost lottery ticket? That's what reading this thread reminded me of - there's value in it somewhere but damned if I can spot it. Suddenly, Dennis sounds like the Voice of Reason!

An Antipodean cousin perhaps?
🤣🤣🤣🤣

[Salty Pete]

Originally Posted by willk

Crikey. Remember the fella who dug up the local waste dump looking for his lost lottery ticket? That's what reading this thread reminded me of - there's value in it somewhere but damned if I can spot it. Suddenly, Dennis sounds like the Voice of Reason!

Yes Willk it does appear like that. The problem is the thread has got too long, and I'm not helping here. People jump on board without reading all of the posts and not understanding the situation.

This results in posters giving me advice on how to solve problems I didn't have as well meaning as they may have been.

This subject has finished now I had a problem it is now solved however the information on the problem I had and how I solved it (with the help of Fenlander) I believe is interesting information.

But, as you said it is buried in so much rubbish any valuable information is lost.

[beerbelly]

Originally Posted by willk

Crikey. Remember the fella who dug up the local waste dump looking for his lost lottery ticket? That's what reading this thread reminded me of - there's value in it somewhere but damned if I can spot it. Suddenly, Dennis sounds like the Voice of Reason!

[beamishken]

But, as you said it is buried in so much rubbish any valuable information is lost.[/QUOTE]

Ok ill be the one to take the bait most posters here know how to prop a boat correctly, your method is far from it. Your calculations are a nonsense & have no helpfull meaning. The fact you think your problem is cured is pure fluke, your engine is now significantly overloaded & at risk of damage & probably using way more fuel than it should. Fenlander was correct you needed to get away from the tricky planing point rpm BUT you should have decreased the pitch , not increased you got lots of good advice from very experienced people & totaly ignored it & could potentially damage your engine running in your "fixed" condition as a result.
Perhaps your just fishing for a bite hoping for an argument but it needs pointed out that what you have done is not reccomend .

[Steve509926]

: sorry Ken, couldn't resist.

I've been waiting all day for someone to do it

[beamishken]

Originally Posted by Steve509926

: sorry Ken, couldn't resist.

I've been waiting all day for someone to do it

🤣🤣🤣
It had to be said just in case someone thought this pi$h was actually correct

[Salty Pete]

Beamishken

I would like you to varify your statements (if you can)

(Your calculations are nonesense etc. etc.)

How do you know? I have not published my calculations.

(The fact that you think your problem is cured is pure fluke)

Guessing is a fluke. Mathematics is an exact science and once again you haven't seen my calculations.

(Your engine is significantly overloaded)

Sure, Suzuki recommends a prop that will overload their engine. Where's your calculations to support this?

(It will probably use more fuel)

A larger pitch reduces engine revs and increases fuel consumptions. I'd like to see your calculations on that one.

(You need to get away from the tricky "Planing Point.")

Firstly don't use another forum user's name in attempt to ratify your rabbiting. Planing was thought to originally have been the problem, but was later found not to be the case. Try and keep up.

(I am fishing for an arguement)

Why is that when your the only one arguing?

[beamishken]

Originally Posted by Salty Pete

Beamishken

I would like you to varify your statements (if you can)

(Your calculations are nonesense etc. etc.)

How do you know? I have not published my calculations.

(The fact that you think your problem is cured is pure fluke)

Guessing is a fluke. Mathematics is an exact science and once again you haven't seen my calculations.

(Your engine is significantly overloaded)

Sure, Suzuki recommends a prop that will overload their engine. Where's your calculations to support this?

(It will probably use more fuel)

A larger pitch reduces engine revs and increases fuel consumptions. I'd like to see your calculations on that one.

(You need to get away from the tricky "Planing Point.")

Firstly don't use another forum user's name in attempt to ratify your rabbiting. Planing was thought to originally have been the problem, but was later found not to be the case. Try and keep up.

(I am fishing for an arguement)

Why is that when your the only one arguing?

The reason no one else has argued is you are so far away from the correct prop selection procedure everyone thinks your trolling & the forum old school have a dont feed the troll policy. You will notice our resident troll has a current thread running & hes happily chattering away to himself.
Almost all the folk who offered advice early on could write a correct prop selection guide & they would all read very similar bur miles away from your nonsense.
Engine manufacturers offer a range of props to suit different sixe boats & loads.
The key is to get the engine ro rev out to max rpm or even slightly over. You can prop lower which is what you should have done but never higher pitch as then the engine is overloaded & bogged down which is where you are now. Running in that condition long term increases fuel burn & risks engine damage.
If you search the forum there are plenty of threads regarding correct prop selection

[Salty Pete]

I don't understand your aggressiveness and rudeness and you are wrong in everything you are saying.

I am going to leave this thread as I have sorted my problem out so you can piss off and be rude to someone else.

[beerbelly]

Originally Posted by beamishken

The reason no one else has argued is you are so far away from the correct prop selection procedure everyone thinks your trolling & the forum old school have a dont feed the troll policy. You will notice our resident troll has a current thread running & hes happily chattering away to himself.
Almost all the folk who offered advice early on could write a correct prop selection guide & they would all read very similar bur miles away from your nonsense.
Engine manufacturers offer a range of props to suit different sixe boats & loads.
The key is to get the engine ro rev out to max rpm or even slightly over. You can prop lower which is what you should have done but never higher pitch as then the engine is overloaded & bogged down which is where you are now. Running in that condition long term increases fuel burn & risks engine damage.
If you search the forum there are plenty of threads regarding correct prop selection

dont waste your time with him its either another pseudonym for that other idiot or a new idiot either way you and others have tried your best

[Steve509926]

To be fair to Pete, he's definitely not Dennis, he's not a troll and I don't think he's an idiot.
He has "resolved" his original problem so therefore, in his eyes, the solution he came up with must be correct and he doesn't need to listen to anyone else's opinions.
The likelihood that he may have caused another more serious problem with his outboard further down the line doesn't matter to him, as his initial problem has been resolved.
What is important, is that anyone reading this thread looking for meaningful advice on selecting a prop/pitch should completely ignore it and search for other prop/pitch threads instead.

[beamishken]

Originally Posted by Steve509926

What is important, is that anyone reading this thread looking for meaningful advice on selecting a prop/pitch should completely ignore it and search for other prop/pitch threads instead.

That was exactly why I posted 👍

[Fenlander]

"you are wrong in everything you are saying" says Salty Pete to Beamishken. Hmmm...

As I tried to help SaltyPete and perhaps steered him in the direction of assessing his revs and changing pitch then it's perhaps unfair to let Beamishken take all the flak.

So Salty Pete...

You say you haven't published your calculations. Well we got enough idea from the whiteboard performance in post 1 of this thread. Truth is that simple (or even complex) maths can't fully predict real life engine/prop/pitch/hull interactions. There are so many variables it would take computer modelling to get anywhere near a result... and even then a simple shift of weight in the boat could throw off the predicted result. A major factor is prop slip percentage which isn't linear across speed.

You hint that Suzuki wouldn't' supply a prop that would overload the engine. Yes they would with anything from an over pitch that risks engine damage to an under pitch that would have it bouncing off the rev limiter at modest speeds. They offer options for so many craft types and trust you make a proper choice.

You seem to think it isn't possible for lower revs with a larger pitch to increase fuel consumption. Well it is possible as load and fuel consumption are a function of throttle opening not just revs. It can be with a larger pitch the throttle opening is higher to maintain the same speed.

On an associated point you say in my post 10 I have it back to front saying the engine may be working harder (and risking damage) on a higher pitch. If you think this is wrong more study of engine theory is needed. Higher loads or even the same loads at lower revs can give the bearings a hammering. Please study Sommerfield and Hydrodynamic lubrication.

And a final point do you really really think an inductive tach on one spark plug would cause an engine to overheat or was that a wind up? The tach is a passive device merely picking up on emissions the plug leads always make. That's a bit like saying the brightness of the moon is affected by the number of folks viewing it.

[Salty Pete]

I think people have lost sight of the original problem that I had. This has resulted in accusing me of not fixing problems correctly that I didn't have.

May I please recap on the original problem and the decision I made to overcome it. And then I would request that you don't just criticise it but tell me how I should have done things differently. I am open to suggestions and I have acted on your suggestions in the past.

Firstly, let's clear up the accusation that I did not select my prop in accordance with the correct procedure. It's true, I didn't because I wasn't trying too. I bought my boat from the Highfield agent who sells nothing else but Highfields and I am sure he knows what prop should be fitted to my boat. So, back to the original problem.

My boat was accelerating to 6 knots @ 2960 revs. and then accelerating to 15 Knots @ 3980 revs without any input at the throttle.

I needed to get a speed of 0 - 15 knots 1020 revs out of that area.

Two ways one to decrease the prop pitch and move the speed of 0 - 15 knots after 3980 revs. That's a joke, the engine would be screaming before you started to move and probably blow apart before you got to 15 knots.

Or, select a larger pitch and move the operation 0 - 15 knots below 2960 revs. This is what I did.

Now, please tell me where I'm wrong.

[willk]

Originally Posted by Fenlander

That's a bit like saying the brightness of the moon is affected by the number of folks viewing it.

Well obviously it's not affected by the number of people VIEWING it silly. But clearly if those viewers take photos of it the flashes will make it brighter!

C'mere - you lads are still digging for that lottery ticket, which is ironic, because you ARE the lottery ticket and more digging is just causing someone to tip in more garbage...

[willk]

Originally Posted by Salty Pete

Now, please tell me where I'm wrong.

You're wrong in Beckenham, Australia.

[Steve509926]

Originally Posted by willk

C'mere - you lads are still digging for that lottery ticket, which is ironic, because you ARE the lottery ticket and more digging is just causing someone to tip in more garbage...

[Salty Pete]

Very funny Willk.

However the big mouths have suddenly shut.

I am leaving the forum, it's like the village of the Damned.

[willk]

.