Whats the best number of blades on a prop?

[Wiggo]

Why do the submaine boys use those 7-blade scimitar jobbies, then? Is it just quiet and they don't care about the power wastage?

Note to self: check on status of Red Uranium under EU rules. Could solve several problems. Understand Navy reactor thingie about the size of a dustbin, so should fit if I get rid of the green meanies. Could also run a microwave without needing a new genset as well.

Pass the dried frog pills...

 

[rickp]

Feeling better today then?

Rick

 

[fisherman]

Where are you getting prop work done in Cornwall? Didn't know there was anywhere.

 

[[2068]]

> Is it just quiet and they don't care about the power wastage?

I'm guessing that quietness could be the difference between survival and ending up like the Kursk. Also, so long as you can push to max hull speed underwater, who cares about efficiency when you have an effectively unlimited power source ?

I'm also interested in the idea of a small reactor for the S28: could be the solution for when red diesel finally bites the dust.

dv.

 

[BrendanS]

I understand the Iranians may be able to assist

 

[No1_Moose]

That may be a little dangerous though, I think you might find yourself going a little higher and faster than you had hoped. Remember, health and safety first.

 

[muchy_]

Any number more than one.
/forums/images/graemlins/smile.gif

 

[Doffy]

Single prop is best???????????????/

 

[Gludy]

Duncan Propellers.in Cornwall.

The latest is that the Durch messed up the props they are not the same diameter as stamped nor the same pitch.
It seems that Duncan got them, mestured them but found that they were not as stated to begin with and not as stamped on the prop - so the Dutch are about to make new ones that are as stamped but I have put a shot across the bows and want an agreed perfornmence criteria for acceptance or rejection .... so the saga goes on.

The 3 blaed props at 92% power gacve about 24 knots so it seems that a small pirch change would give us a few more knots and they cost a fraction of the five blade props.

 

[david_bagshaw]

Re: No- It\'s one!

others have well covered the lesser efficiency of 5/4 against 3


but run your boat & measure the noise in cabins etc nearest props while on 3 blade

you will get a significant reduction in noise from the props on 5 blade


we did a conversion from 3 to 4 blades some years ago and the nose reduction was remarkable.

at the same time we achieved a fuel economy gain by having them pitched to achieve cruising speed to match peak torque from the engines, at the cost of 1/4 knot top speed.

added:-
you say the dutch are making your new set, would that be van der voorden by chance, can well recommend them.