Prop experts and others...please help!
 

before I get too detailed about the set up and the problems I am having I have ONE question that I need answered before I can move forward....

ALL else being equal which will have MORE transom lift:

1) 30p B1 spinning at 3600 rpm (prop rpm)

OR

2) 26p B1 spinning at 4200 rpm (prop rpm)

both have the same "theoretical" speed of 103mph.

someone must know which gives more transom lift....

both will be the same, in theory the 30p should provide more lift because the blades are angled more but it won't be noticeable, changing the rotation can help depending on how you have it now and what kind of boat it is.

figuring out props is a black magic art....before I confuse myself more I need to figure this part out.

Forget the boat, power, drive ratio for a moment.....

so you are saying that a 30p has more blade angle thus more lift....got it. what if the 26p is spining much faster? 4200 prop rpm vs 3600 prop rpm with the 30?

Regardless of what the prop is attached to....which would lift more?

like I said between a 26 and 30 bravo regardless of RPM it will be impossible to notice a difference, the 30 will lift more but the difference is so minute you won't be able to feel it. If you need more lift you need different props or need to change the rotation (only an option for twins)

something is going on....30p at 3600 prop speed gets 90mph, 26p at 4200 prop rpm gets 84mph....should be the same "theoretical" speed from the same power.

But it is not. something about the prop speed that the boat does not like....

Sounds like the 30 pitch prop is slipping less. Now all you have to do is figure out why. Then again you will most likely never find out why unless someone can tell you why that already knows. I suspect that a prop expert could tell you why the 30 pitch prop is more efficient at that speed range. I suspect there is a "best" pitch for a certain speed. I have never heard anyone say what they are for different speeds. To use an extreme example, I bet it would be very difficult to get 150 mph by spinning a 15 pitch prop fast enough. I suspect there would be all type of fluid flow problems at that prop rpm.

It depents also on the weight of the boat ,a Formula 1 type Cat with a S3000 engine will run almost same speed at the propellor shaft ,I believe its 16:19 or some models have 1:1 ratio ,they turn a 17 pitch or a 19 pitch ,to their max speed .
These props are very small in diameter off course ,but they only push around 1100 lbs

the faster you spin the prop the more friction it has with the water and at some point becomes less efficient, I have been told that all of the bravo props except the 34p are good props. I understand you're confusion but you have to remember prop formulas and theoretical speeds are only a guide in the real world there are many variables that when it comes to boats cannot be measured. What is it you are trying to accomplish? Figure that out and then try different props (and gear ratios if you have to) until you get the performance you are looking for.