prop shrouds

[viking north]

Subs, torpedoes, shrouds, water jets , all one big target

Once one of these things lock onto you it's just re arranging the deck chairs on the Titanic boys. Back in the old days with outdated equiptment tuned by us tecks who knew our stuff we'd out kill anyone in war games amoung the Nato nations. A sub was not the place to be,Imagine what these hunter killers can do now with modern gear and active submurged underwater tracking devices. In her belly was two massive homing torpedoes (yes they had rings,why i don't know but it keeps me on the repetitive topic) each one probably capable of taking out an aircraft carrier, certainlly crippling it enought to hold it in one spot, imagine what it could do to to a 60 or 70's era sub. No thank you as far as i'm concerned any sub mission ( with or without prop rings)is a one way trip with a modern version of this bird. Pretty pictures of subs are just that pretty pictures. And thats my last post here as i'm guilty as anyone keeping it going long past it's expirey date. geo.

 

[gonzo]

Prop shrouds are a type of prop cover.
These vary in size from small rings and very simple collars to complex shrouds. A very common misconception among non technical people is that the bare propeller is the fastest in the water...
Well, we don't live in Kansas anymore folks! that's stinking thinking...
So, if you want to enhance speed and performance and increase your powertrain aspect ratio.
You better look into advanced designs. Lets look at the USA's
Navy.Those weapon systems that are of course the fastest objects in the water column:subs and torpedoes.
The Los Angeles class attack submarines all use a propeller ring.(huge)
The MK 48 torpedo(USA'a operational to 2025) uses a full shroud around its multiple propellers. Its speed is 120 knots (more or less but it outruns submarines and they are fast!
If you think the shrouding slows them down you are seriously not thinking very clearly at all. By shrouding the powerful torpedo's propellers it makes them function like a turbine vane in a jet engine and makes the propulsion like that of an underwater jet coming out the rear.

Thanks for listening curious for replies...

The advanced engines for powerboats exhibit this growing trend to enhance spreed and performance by shrouds.So I guess 'old school' holdouts will have to relearn the truths of hydrodynamics by being last to the 'ole fishing hole .


stew

.........................................................
So, this was the original post. Except for a poorly written PM for Waterwar, I still don't see any support for his claims or arrogant attitude.

 

[Jeremy Harris]

So, this was the original post. Except for a poorly written PM for Waterwar, I still don't see any support for his claims or arrogant attitude.

I'm pretty sure this whole topic has just been a wind-up, right from the start. The thread should have died after the first couple of posts pointing out the basics about pump jets vs props.

I've no doubt that someone is just sitting at their PC chuckling at their ability to get normal folk to waste their time.

These are exactly the sort of antics that have caused other useful contributors to stop posting here, to everyone's loss.

Jeremy

 

[waterwar]

forget my request for a review of Prop guard or what?

So, this was the original post. Except for a poorly written PM for Waterwar, I still don't see any support for his claims or arrogant attitude.
_________________''people want the weirdest things''_
Gonzo

You also think that wanting to know information and establish a free exchange, so someone could actually use this site to make a logical choice is weird. In a crowded field of products and me asking for advice from a board of peers?

You are supposed to know if you are so senior...sometimes the thread can change as discussion and posts open up and ideas exchange.

For instance, I note that you ignore the request I made regarding the Prop Guard claims completely in the above short outburst ?
Nothing at all about the excellent analysis of some test data on a prop guard.
That the very analysis revealed the design of the original patent had changed.
So its not apples to oranges! It's one product that is newly designed. You also dismissed entire subject as nothing new on an earlier post....

Comparing a shrouded prop or pump jet to a larger prop is unfair! .
USN subs and the Mk 48 torpedo which carries a very heavy payload the pump jet with its counter rotating 'propellers'' is' emulated in civilian applications. Its use here and in some very fast attack Subs was mentioned by a fine member of this board!
.http://www.youtube.com/watch?v=zTohYRUt_2c

pictured below USN attack sub,USN ballistic missile subs lastly Mk 48 torpedo

 

[waterwar]

I'm pretty sure this whole topic has just been a wind-up, right from the start. The thread should have died after the first couple of posts pointing out the basics about pump jets vs props.

I've no doubt that someone is just sitting at their PC chuckling at their ability to get normal folk to waste their time.

These are exactly the sort of antics that have caused other useful contributors to stop posting here, to everyone's loss.

Jeremy

I am disappointed of course but I do think that some serious thought should be done about wasting normal people's lives who write in for advice and get;
some wise *** shooting off

go to another beach
at least I did what was asked some years ago...

 

[waterwar]

Here are several photos of the one discussed. (Different colors for different hp.) Thank you all very much for the positive review of a product I wanted to buy. I came here because I was looking for some honest and straight talk about a propeller shield, not wise jabs and curt answers... In any event, I am an fish farmer and think that something has to be done to stop senseless deaths of manatees. I did get a lively discussion. (Those members who contacted me privately so as not to reveal wanting to know more about prop shielding will remain anonymous, of course.)
Regards,
Stewart Loeblich
P.S. I posted numerous shots Chinese boats and one of a Turkish boat, plus many of USN subs and torpedoes b/c someone had posted a crown in a silly pic attachment and I did that to "flood" it out.

I don't want a better prop shield for military, I want it for recreational use and commercial inshore craft. Thanks.
https://sites.google.com/site/preservethemanatees/

 

[Scunthorp]

Why aren’t people eating these things? I will bet they taste good with some curry powder. Save the seals has almost wiped out the fishing industry here. John

 

[Scunthorp]

On reflection disregard my last post as it could be deemed offensive to the “homo-vegetarian sensitive type” besides the oil that BP’s brightest has dumped into that eco system will make them taste funny and probably provide a non intentional solution to your prop shrouds problem.

http://www.savethemanatee.org/news_feature_oil_spill_6-10.html

 

[waterwar]

Originally Posted by viking north
Waterwar, the topic is a good one and has been ongoing one over the years, it's an interesting topic and worth some new input The problem i think was in your excitement to create debate you took the wrong approach by using the tool of confrontentation to create debate instead of querry. We're probably all guilty of this at some point in our life, it's usually a sign of higher levels of tetosterone thus the question on your age.Good for you if your levels are high but bad for you if you want meaningful debate. Thats why old guys mellow and become more patient and wise. So me thinks if it's not too late you could re tone your post and a transfer of info could possibly occur. Geo.

A yacht is not defined by the vessel but by the care and love of her owner.

Agreed. Except for me, we are not idiots here. These are in great part professionals with centuries of combined knowledge.
__________________
Cheers,
Hoyt
http://www.weathercenter.usf.edu/weathersticker/
http://arctic.atmos.uiuc.edu/cryosph....new.some.html

Sub Tommy

you've broken my Heart by retracting you post how quaint?

how could you now the cat will eat em' all

"Life is like a field of newly fallen snow.
Where I choose to walk every step will show."
Author: Denis Waitley

 

[waterwar]

On reflection disregard my last post as it could be deemed offensive to the “homo-vegetarian sensitive type” besides the oil that BP’s brightest has dumped into that eco system will make them taste funny and probably provide a non intentional solution to your prop shrouds problem.

http://www.savethemanatee.org/news_feature_oil_spill_6-10.html

I think that reverting to this level of name calling and such is a sign of your immaturity.

Often it is the case:When people resort to using hate rhetoric it is an attempt to cover up their insecurities as to their own man hood. I am not a vegetarian, I am not gay, so your definition is inaccurate

 

[viking north]

Stop feeding the beast(thread) it will die.

 

[waterwar]

Chumming is a fishing practice .
Being a fisherman I can assure you it is very effective. I am not a spy for some unnamed country trying to get secret technology.
If this persists I'll publish the ridiculous stuff I have been sent in private..
Everyone will laugh their ____ off when they see that range of paranoid and strangeness ..

However I really am not a 'beast' and won't embarrass people just for spite... that's counterproductive

 

[waterwar]

'Vows made in stormy waters are forgotten in calm ones.'

I appreciate your sage advice I want to thank all who have given so much of their time to share knowledge on a very complex problem
The advancements in the last fifty years in marine propulsion are impressive.
I want to thank everyone for sharing here.
Putting all those ideas on a subject such as you all have shown willingness to do..
In particular, l I want to thank the various engineers who shared their knowledge on the complex subject freely.

If you look at the old threads the subject was dismissed go to another beach

we need to advance this application; to find one that does work reasonably well
I mean no endorsement of any one product unless it works does the prop guard live up? what could be made different?

thanks
stewart

I asked a question and it was very well answered. By real experts on this very board . Guess you were 'strumming' then....playing with ___self

Where else could I get a very intelligent detailed analysis of a particular type of prop shroud? I would have to pay hard cash for such a service!

Thanks to you professionals that did help ...the others read and learn.

 

[gonzo]

You should re-read your own post. There was not question but a lot of snooty remarks. The negative reputation points are a reflexion of what members think of you. Except for a bad attitude, you haven't answered or substantiated anything.

 

[waterwar]

I asked a question and it was very well answered. By real experts on this very board . Guess you were 'strumming' then....playing with ___self

Where else could I get a very intelligent detailed analysis of a particular type of prop shroud? I would have to pay hard cash for such a service!

Thanks to you professionals that did help ...the others read and learn.

Quote:
Originally Posted by waterwar
'Vows made in stormy waters are forgotten in calm ones.'

I appreciate your sage advice I want to thank all who have given so much of their time to share knowledge on a very complex problem
The advancements in the last fifty years in marine propulsion are impressive.
I want to thank everyone for sharing here.
Putting all those ideas on a subject such as you all have shown willingness to do..
In particular, l I want to thank the various engineers who shared their knowledge on the complex subject freely.

If you look at the old threads the subject was dismissed go to another beach

we need to advance this application; to find one that does work reasonably well
I mean no endorsement of any one product unless it works does the prop guard live up? what could be made different?

thanks
stewart

Read like the lil red question up there?