Re: Going to 21 from 19 pitch?
Hmm... how to explain. 1st of all, I might have this backwards, so I apologize in advance if I screw this up. Somebody who really knows will correct me if I'm wrong.
I believe, the higher the pitch number, the faster a boat can go. It's kinda like gears on a bicycle. If you have a LARGE gear on the front by the pedals, and a tiny gear at the rear, by the wheel, you have the capacity to make that bicycle go VERY fast. Whereas if the front gear is smaller, and the rear is larger, you can pedde like crazy, and not really go anywhere.
BUT... and this is the big BUT. You can't climb a hill very well with a large gear in the front, and a small gear at the rear wheel. You'll be standing on the pedals, and just not have the torque to make it up the hill. However, if you have a small gear at the front, and a larger one at the rear, you'll make it up that hill like it's a piece of cake.
Why did I say all that about bicycles? Well, trust me it'll make sense.
If you have a Tug Boat... the pitch is a very LOW number. Meaning that prop is turning pretty dang fast, but the boat itself isn't moving very fast. HOWEVER, it's got a TON of torque to push all those barges up and down the river/accross the lake/etc. Tug boats might not win any races, but there's no WAY your 90mph off shore racer can push 25 barges up the mississippi. First off, you would damage the hull, but mostly it's because all that power on the offshore racer, is designed to make it go FAST, not push a lot of weight.
SO.. how does this relate to your boat? Getting a higher pitched prop, even a small difference, means that your engine can turn less RPM's for a given speed. If your reaching redline on your motor, and doing a measly 35 to 40mph, and you know the motor has more power, just no more RPM's left, then getting a higher pitched prop, means you can possibly hit 45mph, or maybe even 50, if the motor has enough power. BUT... it will have less power at low RPM's for the holeshot.
Where as... if you are wanting to pull say... 3 skiers out on slolom, with your 19 pitch prop, it may have some difficulty, draggin those skiers through the water for a while before popping em up. Where as if you switched to a 17 or 15 prop, for the same amount of power, you're gonna have more torque, and pop those skiers out faster. you will lose some top end speed, but you'll have more power at the low end.
Is that making any sense.
I hope so.
Just think of the pitch of your prop, as the gear select on a bike. You can only make so much power, you just have to decide, do you want it to work for you at one end, or the other, low end grunt, or high end speed.
Most manufacturers, try to sell a "medium" pitch blade for any given motor, so that you get the "best of both worlds", with a pretty good holeshot, and pretty good top speed, and they try to find the "sweet spot" right in the middle. So if you're happy with your motor, and holeshot, and top speed, I wouldn't change a thing
If you want more top speed, get a prop that does that, if you want more low end grunt, to pop those skiers out, get a prop that does that, but just know that you can't do both with the same prop ok. Unless......
oh boy you're gonna hate me.
unless you get a variable pitch blade. You of course have to remove the prop to adjust the pitch, but you can get one prop that has variable pitch blades. Kinda pricey ussually, and not always as good as the fixed pitch prop, but pretty cool to play with!!!
