4 blade prop differance?

[Blujay96]

I have a 1987 rinker v180 with a 3.0 L 4 cyl it is 17'6" and weighs 1900 dry plus 20 gal gas 4 adults. I have never had it in the water yet, but some have told me to get a 4 blade prop for it. When I got the boat it came with a 3 blade prop. Can anyone tell me what the advantage of a 4 blade prop would be. Thank you

 

[superpop]

Re: 4 blade prop differance?

4 blade prop typically gets you less vibration and more bite out of the hole. RPM's are decreased as you are pushing more water, and they tend to work better for water sports were you need holeshot. They are not the holy grail though for fixing other problems like not enough horse power.

 

[Blujay96]

Re: 4 blade prop differance?

Ok with the information I gave earlier and that it is a 1.98 ratio alpha one drive 130 hp, max rpm range 4400-4800. What would be a good 3 blade and 4 blade prop to put on the boat

 

[Blujay96]

Re: 4 blade prop differance?

Here is the information, I just found these in the forum. Hopefully it will help in the calculations.

1. Year, make and model of boat
1987, Rinker, V180
2. Length, width and base weight of boat, look for boat decal on back of boat
17'6", 1900 lbs base weight
2a.What is the recommended HP for your boat
130 hp
3. Number of people and gallons of gas normally on boat
3 adults, 2 children, 20 gallons of fuel
4. What do you use the boat for
Cruising, skiing, kneeboarding
5. Is it a Deep Vee and if so how many degrees of deadrise
Vee Hull(Not sure what the degrees of deadrise is)
6. Year, make and model of motor
1987, Mercruiser, 3.0L 130 HP 4 Cyl
7. HP and gear ratio of motor IMPORTANT
130 HP, 1.98 Ratio
7A If you have a mercruiser and don?t know the ratio get your serial off the outdrive and go here http://www.sterndrives.com/mercruisersterndrives.html
8. Manufacturer?s recommended Wide Open Throttle (WOT) range
4400-4800
9. Anti-ventilation Plate height above keel of boat if it is an outboard in inches
10. Is it a bass boat or does it have a pad bottom
11. Does it have a hydrafoil, dolefin or trim tabs
It has what I consider a whale tale that has been bolted on.
12. Make, model, diameter, pitch and whether SS or aluminum prop
13. WOT RPM and speed from your current prop and how much gas and how many people were in the boat for the test data and is the speed by GPS. If you do not have a tach you can buy a Tiny Tach for $ 50
14. Are you at sea level or a higher elevation, give us the elevation in feet
Sea level
15. Has your motor been tuned up lately and have you checked that the carburetor butterfly is opening all the way, checked compression, and looked at the plugs and checked spark, all of the forgoing could be the reason your prop is not attaining full RPM
16. How long has this prop been on the boat and why, at this time, do you think it is the wrong prop
17. Does the prop show any damage that you can see
18. What problems are you trying to cure or what are you looking for the boat to do that it is not doing the way you think it should or to your expectations
Want the best prop for the boat before I start.

 

[Yepblaze]

Re: 4 blade prop differance?

I'd say run what you have.

 

[Blujay96]

Re: 4 blade prop differance?

I never said what I had other that a 3 blade, so how could you say run what I have. My question was what would be the best prop. The one I have is beat up and I would like to buy the proper one and heard 4 blade were better for planning and hole shots

 

[hwsiii]

Re: 4 blade prop differance?

Blujay, you want your motor to turn maximum RPM at WOT with one person and a full fuel load in the boat. You are saying you possibly want a 4 blade prop for cruising, skiing and kneeboarding. In order to maximize the selection of a new prop it is ALWAYS best to have a baseline on the prop that you have now. The first thing it does is let us know how much prop slip you have with your current prop and how efficient it is pushing your boat right now. it is not Magic doing this, it is science at the beginning and then at the end it is an Art.
The information being asked of you is for Your benefit in trying to selet a better prop than the one you have now. You are talking about having 3 or 4 people in the boat while you have someone potentially skiing behind the boat, that is a lot of load for that motor to be pulling, probably a 4 blade would be better for your purposes, but not always. That is why we ask all the questions we ask.


H