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Need prop advise

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marada1

Regular Contributor
"Boat is a 1991 18ft Marada wi

"Boat is a 1991 18ft Marada with 1990 (pre balance shaft) 4.3 Cobra. I have added Vortec heads and Edelbrock Performer manifold, 1409 carb, and K&N arrestor. I'm estimating HP around 215-225. Current prop is a 14.3 X 21" Solas "Amita" 3 blade aluminum. WOT RPM is right on at 4500-4600 @ 50MPH w/GPS. Hole shot is not great. I have the same prop in a 19". Engine obviously over revs with it. I've seen 5000 and had throttle left over.
I am looking to improve hole shot and not give up too much speed. I'm torn between a vented SS 3 blade or a SS 4 blade such as the Solas HR Titan 4. I've read Hystat's comments on the Raker and I'm wondering if it would be a good fit for what I'm trying to do. If so what pitch would be recommended? I've seen a couple of 20" Raker for sale. If I decided on a 4 blade what pitch would you guys recommend?
I've attached a couple of before and after pics of my boat that should give an idea of hull design. BTW dry weight is around 2640 lbs.
Any input would be appreciated.
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boat1"">
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boat2
 
"Hi Chuck, I can't really

"Hi Chuck, I can't really help you much with the prop issue. It sounds like you are really propped pretty well right now. Maybe you want to try a dolphin fin. That may help your hole shot without affecting your top speed too much. Maybe...I don't know that much about it.

Not meaning to hijack the thread, but how impressed (if at all) are you with the K&N arrestor? I had no idea they even made one. I use K&N's in all my other vehicles, and was just wondering."
 
"I'm pleased with the K&am

"I'm pleased with the K&N but I really don't have anything to compare it to. When I upgraded to the 4bbl I wanted to be sure I had good air flow. Besides my original arrestor on the 2bbl was pretty beat up when I got it (just like the rest of the boat). Like you I run K&N on my truck and I knew their reputation is good. They are a little pricey. Got mine from Summit for around $90. It's the 2" x 9" natural stainless steel.
Not really a fan of the "fin" attachments. I feel like the right prop will do what I want. Kinda leaning towards the 4 blade for the hole shot (pulling skiers etc) and for the cruise speed performance/fuel economy they bring(I think). Just not sure what pitch to try. I'm think'in the 21" but hoping to hear from some experience here on marineengine.
Thanks for your thoughts

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"I hear you about the fin. Ano

"I hear you about the fin. Another alternative would be some tabs, some good write ups about "Smart Tabs", they will improve your hole shot without putting any extra stress on the drive. If you are going to try a 4 blade generally you come down an inch in pitch compared to the 3 blade so you would want to try a 20. Maybe you can arrange with whoever you are buying from to try a couple of different ones?"
 
"Yeah, a few years ago we had

"Yeah, a few years ago we had a local dealer that would let you try props. Unfortunatly they are gone and the one shop that is left really doesn't stock much.
Bob, what do you think of the Raker idea? Also what 4 blade do you recommend if any? I've heard good things about the Solas I mentioned but they} come in odd pitch sizes and I really don't think I need a 19". Thats why I was think'in about the 21" The Raker however comes in even sizes."
 
Did a little research on the s

Did a little research on the smart tabs. Didn't really find any explanation as to how they work. What holds them up at planning speed? Water pressure? Looks like they would create drag at all times. Maybe someone can explain them better?
 
"I would try a stock 3 blade 2

"I would try a stock 3 blade 21P Stainless OMC prop, or a 20 Raker."
 
"Chuck...from what I can tell

"Chuck...from what I can tell the spring tension keeps them down at rest which is what you want to to help lift the transom and get the bow down quickly, as you pick up speed the water pressure overcomes the spring tension up to a point where the tabs level off with the hull so in effect they just become an extension of the hull much the way Bennett hydraulic ones do. The only disadvantage is you have no control individually to make any adjustments for side to side levelling but then they don't cost nearly as much either."
 
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