If you are running the OEM prop, you have your work cut out for you. You have a load in the stern and the only way to get that up (besides engine trim positions) is to get some thrust out of the prop. What you are describing is that the prop has too much pitch for a properly executed "hole shot". You seem to be fine on the top end with your 19P. Basically you need 2 props in one.....one with less pitch so the engine RPMs can get up faster, shortening the hole shot time, and the one you have for top end performance.
Enter the "ported" prop....holes in the barrel, usually 3, one for each blade. The ports let exhaust gasses flow across the blades reducing the density of the medium in which the prop is trying to turn. By introducing air (engine exhaust) across the blades you decrease the density of that medium and the RPMs can get up faster and with the prop turning faster, you will come out of the hole faster....once you fine tune your trim for the best hole shot....trial and error on trim position. Once up to speed....20 MPH for a number, the new water, water pressure entering the blades, seals off the ports and they no longer function as you don't want to use them at speed.
Only aluminum prop of which I am aware is the Turning Point (Brand) "Hustler". It's an aluminum prop with special aluminum and processing to reduce the tendency for the blades to deform under high thrust loads. Blades can't be as thin as with SS (helps top end speed) but they due process their aluminum to resist any deflecting. All of mine (currently have 4) are ported and have blade tip "Cupping" for better grip in high trim angles and in turns, and have a high "Rake" factor....the blades don't come straight out from the root at the barrel, they lay back providing better grip on top end and in certain water conditions.
The good news is that being aluminum, they are priced where experimenting won't cost you an arm and a leg. Easily obtained...just plug the name into a www search engine.
The cupping is said to act like 1" of increased pitch so that "may" drop your RPMs below the half way point on recommended RPM range at top end.....may not. The Rake will improve grip on top end in addition to providing improved bow lift at speed, so that too may, probably will impact top end RPMs too. With any prop on any boat with any engine, the only REAL answer is to run it!
Note: The Rake improving bow lift isn't to be compared to the hole shot. Rake is for the high speed end of the boat's performance.....hull drag caused by it touching the water is the main thing that slows you down at speed. Rake helps to raise the bow just a few degrees but that can make several MPHs improvement in top end....may offset the effect of cupping loading your engine, slightly reducing top end RPMs......giving them back to you if you decide to go with the TP 19P.
Tossing my hat into the ring, which I have done many times over my 50+ years of boating, for around a hundred bucks (may be...probably... higher since I last bought one but a lot cheaper than SS....for a little less performance) I would go ahead and start with the 17P in the 13" diameter range of props that fit that lower unit. No doubt once you tweak your trim for optimum, you will experience an eye awakening with your new hole shot! With the other improvements in the Hustler, the 17P will surely put your RPMs where you want them on the top end....with a little luck, you won't loose any top end speed.....with the correct trim....once you figure that out.
Good Luck and happy boating!
