4 bladed props any good on legs

[lucyloo]

any one no wat they r meant 4 ?

[Spaniard_King]

Lucy

There good for offshore situations, having 4 blades they are very efficient at low rpm (trolling) and also means they are good for holeshots. They are also good for bar crossings minamizing slip in rough/airated water.

There not meant for high speed aplications as the high blade area sucks the hp from an engine at the upper end of thr rpm range.

I run a 4 blade Solas on my boat

Garry

[bassfanatic5]

Garry,
Just wondering why you say 4blade props are no good for speed. We have tried a series of different props on my new labsport and the fastest prop out of all of them has been the bombardier Bass Renegade 4 Blade. Much slower at idle through to 4000rpm but from there it leaves the 3 blade's behind. At 5800rpm the 4 blade is 5mph quicker than the same pitch 3 blade. May just be my hull but thats my experiance after trying 5 different props.

Damien

[Dignity]

Damien, I tend to agree with Garry as I use my boat mainly for offshore. I don't know about 4 blades but I have a 5 blade high five on my allison an it does lose a lot of top end speed although when I push it pretty hard it is very very thirsty. Is it possible that with more blade area at high speed the prop is probably starting to spin in its own cavitiy that it has created. I certainlt get that feeling which is why I am looking to dropping to a 4 blade or even to 3 blades, fisrt got to fix the tacho as it has mysteriously died.


sam

[Spaniard_King]

Damien,

all Boat/motor/load combinations will be different, but in the majority of cases the 3 blade would win out over the 4. It basically comes down to friction/drag which has a lot to do with prop design. With a 4 blade, generally it would have more blade area therefore more friction/drag so an outboard should be able to push a 3 blade harder than a 4 blade.

Take a look at the race boats, some of them run 2 blade props :o for this very reason


Garry

[thesimmos]

I had a 4 blade on my 40hp yamaha. (Old model)

I dont know if it made much of a difference but it might have given more torque at lower speed from what I have been told..

I dont know if it would make much of a difference tho on a smaller boat, I am sure it makes a difference on thing such a sailer cruisers and big motorboats like those bastard rivieras that almost sink me now and then in their wake... needing to push such a massive weight definatly would need a torquey prop..

Note: If you own a riviera they are nice boats just look out for the tinnies with that massive displacement hull you have while you are busy posing.. :)

[lil_boatie]

so what would a four bladed prop go faster that a three bladed, if the two boats were placed in the same conditions?

[Spaniard_King]

LIlboatie,

I have tried a 4blade torquemaster and a 3 blade new saturn on my boat.

I would have needed a digital tacho to tell the difference in RPM, what was different was the holeshot. The 4 blade won hands down

Garry

[Owen]

Garry,
Is the four bladed less efficient at low revs?
The reason I ask is that I have trouble going SLOW enough when trolling sometimes but I want to put a bigger pitch prop on to drop my WOT a bit as well.
I always thought 4 blades was more suitable for larger boat/motor combos.
Might have to spend a wekend with th mother inlaw at Hervey Bay so I can pester Solas till I get the right one ;D
Cheer,
Owen

[Spaniard_King]

Owen,

The 4 blade is way more efficient than the 3 blade.

You have 3 choices buy an etec cause they can idle extremely low or get an electric and finally....... drag the anchor whilst ya towin ;D ;D

Garry

[Owen]

;D ;D
Haven't done the anchor thing yet, but I might give it a go.
The burley pot has ahd a few runs out the back but doesn't quite have the drag.

Anyone ever used one of those plaes that fold down behind the prop?
I saw them on the Solas site. "Troll Easy"
Looks like another thing to go wrong to me, but it's an interesting concept.

http://www.solas.com.au/troll.asp

cheers,
Owen