different props.... MW, PT, Solas

[MBAKER]

I'm curious if anyone has had similar experience with Solas props.

About a year ago we had been running a Powertech aluminum 3blade 19p and would run at rev limiter of our Merc. Decided to try 4 blade and local shop had a 19P Solas aluminum, thinking we could sacrifice a little rpm due to the 4th blade and be good. When we tried it out it was way over propped, would bog down, and pulled WOT rpms down to about 4200, (from 5000). Went back and the shop swapped it out for a alum MW 18P 4 blade, and it ran right up to about 4800 right where we were shooting for.

My question is.... I'm curious if this is typical of Solas props, are they just more aggressive in a given pitch that this result is normal? They looked like a very nice prop as far as how they were finished we just didn't get the result I was expecting. Looking back on it, maybe we should have tried a 17P (or 15P) and see what happened. If they are holding water that much better, then maybe we just needed to pitch down a little more.

Otherwise the MW 4blade has performed well, it seemed to respond better at low speed and hold plane a little slower which is what we were after compared to the PT 3 blade. But alas my dad apparently made contact with something last weekend so we are going to replace it likely with the same thing as we know what to expect.

I also noticed Powertech is now making a 4 blade aluminum prop as well, shop says they are same as MW or Mercury aluminum. The shop thinks they are better made and stronger and Ill admit they look to be finished a little better than the MW. Does anyone have any thoughts on these or experience?

Am I missing out on the Solas? Is it possible the 3 blade Solas would grip better than the MW or PT 4 blade?

 

[ondarvr]

There is no way to compare one brand to another, or 3 and 4 blade props, they all perform differently, it's a try it and see what happens experiment.

​Even though the numbers may be the same, switching brands, or even to another model within the same brand, can yield very different results, and going from 3 to 4 blades normally requires a drop in pitch.

 

[MBAKER]

I understand all of that.

I guess my questions is more along these lines.... From my limited experiment it appears the solas is a different design among aluminum propellers, whether it be more rake, cup, etc. I was curious if that was typical experience others had had, or if I possibly got a random mis-marked or mis manufactured prop. I just wanted feedback to see if others had the same outcome and that I didn't just jump to conclusions about all solas props in general. For the most part I have been able to go between the Michigan and Powertech props and they have behaved as expected, this Solas just acted so much different I wanted to get others input.

 

[Sea Rider]

What's the min-max wot rpm range factory stated for that Outboard/Inboard engine ? with 4800 rpm achieved is it closer to middle wot rpm range or it's already at the near max rpm range ? Can have a prop blade repitch to say 0.5 to fine tune up or down any wot revs that will like to correct, as one full pitch could be too much.

With outboards set ups have a personal issue with this "best prop gripping" for that to happen prop must spin/ grip with a minimum water bed level, with OB well trimmed for all blades to recieve the incoming flattened water flow at top angle of attack. How could a standard 3-4 blade prop grip right when there's insufucicient water bed level. It's like swimming with fingers widly opened, top forward thrust is lost, check it for yourself.

Happy Boating

 

[MBAKER]

well to follow up on this....

Replaced the MW 18P 4 blade with Powertech 18P 4 blade. Noticed the blade design was different and the PT has a longer barrel with only slight flare. On the water, the PT seemed to turn easier and felt like it had a little more hole shot but it did rev higher on the top end and ran into the rev limiter just over 4800 and still had more. Also at cruise and low speed it seemed to take a few hundred more rpm to plane, and stay on plane but I did feel like the boat rode higher in the water like the PT was a better lifter. In the end it feels like the PT may be slightly less aggressive or pitched a little differently than the MW prop, a 19 or 20P may be a closer compare to the MW 18P. Also at least in this prop, it felt a lot like a 3 blade the way it acted just on plane, but a little more pitch might have helped that too.