Solas Amita 3 Blade vs Amita 4 Blade Selection

[HorsePix]

I purchased a Solas Amita 3 (11-3/8x12) for my Yamaha F60. It turns 6300 RPM @ WOT. I want to buy a Amita 4 blade for running the shallows. I know that if I were to increase the pitch by one on the Amita 3 my RPMs would drop 200. Will I experience the same proportional shift in RPMs with the Amita 4? I need to get the RPMs down to 6000 or less. Going from a three blade to a four blade should drop my RPMs 200. Should I increase the pitch from 12 to 13 and end up with 5900 @ WOT?

 

[Starcraft5834]

any increase in pitch, whether 3/4 blade will reduce rpms...if you want to go down 400, 14p might get u closer..... the 4 blade will improve your hole shot and and stay on plane longer at slower speeds

 

[Sea Rider]

Was 6300 wot rpm achieved while light, medium light or fully loaded ? can't you run the shallows with current 3 blade prop ? How is hole shot ? Depending on you load + 300 wot revs is nothing, can compensate adding slight more load or throttle less when at wot.

The Rule of Thumb of + 200 wot revs per one less pitch and vice versa, does not always dials, will depend mostly on load and HP.

Happy Boating

 

[HorsePix]

The 6300 was with the boat fully loaded. I have a Yamha prop that is the same size as my Solas Amita 3 (11-3/8x12x3). The Yamaha turns 5900 @ WOT and the Solas 6300. My Yamaha F60 should turn 5000-6000 RPMs. I want my Carolina Skiff to pop up as quick as possible in skinny water and other CS owners have experience good results going to a four blade. I should loose 200 RPMs going from a 3 to 4 and another 200 increasing the pitch to 13 bringing my WOT within specs. My biggest concern is that the blade properties are different between the Solas four and three.

 

[Sea Rider]

The 4 blade prop you intend to buy will need to rev at near or max wot rpm range of 6K as usually loaded, if going for it, report achieved max wot rpm, just for the record..

Would be interesting to see if the Rule of Thumb applies or exceeds rpm for your application.

Happy Boating

 

[HorsePix]

Evidently there is a substantial difference between the blade design of the Solas Amita 3 and Amita 4. The Amita 3 - 12 pitch turned 6300 rpm @ wot. I calculated that the Amita 4 - 13 pitch would turn 5900 rpm. It actually turned a disappointing 5100 rpm. So much for my propeller mathematics.

 

[Sea Rider]

Thanks for posting data. What a great wot rpm difference between both. What don't get is why near everybody recommends 4 blade props when 3 blade ones performs right, a matter to dial the right pitch for current application.

What do you plan doing ? If staying with current 3 blade one, + 300 wot revs is nothing, add more weight or throttle bit down when at wot to compensate.

Happy Boating

 

[HorsePix]

Thanks for posting data. What a great wot rpm difference between both. What don't get is why near everybody recommends 4 blade props when 3 blade ones performs right, a matter to dial the right pitch for current application.

What do you plan doing ? If staying with current 3 blade one, + 300 wot revs is nothing, add more weight or throttle bit down when at wot to compensate.

Happy Boating

Thanks for the reply. The Solas props are spares as I use a Yamaha prop as prime. The confusing thing I have found is the major differences between manufacturers. My Yamaha 11 3/8 x 12 turns 5900 rpm WOT while the Solas 11 3/8 x 12 turned 6300 rpm. I did throttle back with the Solas and it will be a suitable prop for my use. The four blade will have a new owner. It pays to "try before you buy" if you can!

 

[Sea Rider]

Most times it's impossible trying a prop before buying, that's why like sticking with OEM props than going for alternative brands. With respect to mentioned Solas 4 blade prop, if wanting revving say 6K at wot, would a 11 pitch same diam prop dial + 900 lost revs ? In your opinion would you say that buying 4 blade props are way more tricky to deal with than 3 blade ones ?

Boaters switching from 3 blades props to 4 blades as you did, should report back their personal experience, if it was good, bad, +,- rpm comparisson achieved, etc so to inform others and be aware on the subject. As we have seen forum dry theory recommendations most times does not dials or equals wet practice experimentation. LOL!!

For the connoisseurs :
If 3 blade props dials somewhere between 200 to 500 + wot revs per one less pitch, what rpm range would you give to 4 blade props per one lesss in pitch while maintaining same prop diam ?

Happy Boating

 

[HorsePix]

This was my first walk in the four blade park and I obviously miscalculated the results. The combination of going from a 3 blade to a 4 blade PLUS up one pitch resulted in a loss of 1200 RPMs - I calculated 400 rpm loss based upon 200 rpm per event. Once again the differences in the 3 blade between manufacturers is equally confusing although not as drastic. I don't believe that Yamaha makes a four blade aluminum prop - that would have been my first choice.

 

[Sea Rider]

If Yam prop delivers 5900 wot rpm fully loaded, you're only 100 rpm from max 6 K. Could repitch prop 1/2 pitch less at a prop shop and rev bit higher. Went for a 4 blade prop thinking that dialed wot rpm close to 6 K including any other boating improvement ? There are way more 3 blade prop pitches close to each other to choose from than same 4 blade props.

Happy Boating