Can someone school me on props?

Hello, I recently purchased my first boat, '06 semi-V Alumacraft Waterfowler 15 w/ a 25 Yamaha T/H 25.
It has the stock aluminum prop, but one of the blades has a pretty good chip in it. The boat planes out well already, but i am wanting to get as much speed out of it as i can. I fish Rivers and some good size lakes, which means I run the boat for some pretty long stretches. This being my first boat i am completely clueless as to what pitch prop i should look for, the best place to get it from, etc....lol...I considered a jack plate, but upon measuring the fin right above my prop, it is about 1" lower than the bottom of the boat. Is that good or can it be flush w/ the bottom? Sorry for all the questions, i did search but i just need someone to explain the whole relation between degree pitch and speed..

Thanks!
Stephen

Im not an expert on props by any means lol, but the higher the pitch, the higher the speed BUT you might notice itll take a little longer to "get outta the hole" and go for a stainless prop, way tougher!

Too much pitch,to low of RPM's,= bad for motor.You have to stay in the manufactures recommended RPM's for your motor.

As far as your motor height goes your cavitation plate can be even or slightly above your boat bottom.Just don't go too high that you don't pump water.Yes, the higher your motor is the faster you'll go within reason.

I do not know as much as a lot when it comes to propellers, but what I have been told is think of your propeller as a gear. If the propeller is too large, or with too much pitch--it will try to push too much water, and your motors RPM will drop. This will result in a drastic loss of power, gas mileage, and is harmful to the motor. Likewise, if you put a propeller with too little pitch or one that is too small for the motor, it can cause the engine to run at a higher RPM then desired at WOT. For obvious reasons this is bad for the motor, and again--makes the motor less efficient.

I believe typically people do not change much from the 'stock' propeller size and pitch. You can increase your pitch size by like 1 degree and get a little more top end--or you can decrease your pitch by 1 degree and get a little quicker hole shot. (Double check that with someone else--I may have those backwards) either way, I would not stray too far from the stock size.

Ways to increase your top end would be to lighten the boat as much as possible. Redistribute the weight better on your boat, and make sure your motor is properly trimmed. Also, you could use a product like "STEELFLEX SUPER SLICK EPOXY COATING #9X-2000"... its used for airboats and minimizes the drag on the bottom of your boat, and also gives you added protection.

not to be a thread jacker but this may come in useful if someone can answer for me? I've got to assume that weight of boat, drag and all that other stuff have to come into play as well as motor specs? I would with laymans rekoning assume that if your boat is on the lighter end compared to others a higher pitch would be acceptable because it is pushing less weight and not causing so much strain on said "movin machine" , for instance, my 17.5 foot lowe commander is rated for 85 and currently has a 60 with a 17" pitch, but with all the mods and weight reduction I'm down from the 640# factory weight to right at 500#, maybe less. I intend to put a 19" (and am strongly considering a 21") , the 21 may be a bit much but as quick and strong as the hole shot is right now, I can't bring myself to worry too much. Yeah, I might waste a couple bills on the 21", but like the great RICKY BOBBY "i wanna go fast"

Yamaha performance bulletins shows an Alumacraft Fisherman 145 with F25 using an aluminum 9-7/8 x 10-1/2. Part number 664-45945-00-EL. You can type yamaha performance bulletins into a search engine and fill in the blanks such as boat type, 4 or 2 stroke, Hp range etc and it'll bring up that info if they've tested it or the closest thing to it that they have tested.