thoughts on prop change (help please)

18 ft parker, 130 2 stroke, estimated 3000# avg. load, clean trailer hull.

Presently have a SS 19 pitch (3 blade) rather sluggish comming out of the hole, top RPM 4900/5100.

Most of my cruising is in the 3400/3700 RPM range (ugh), and seems to love the fuel a bit too much. Slow manuvering speed is considerably faster than I'd like. Coming thru breachways,,, well, more oomph when needed would be nice.

Prop change;
Thinking a switch to a 3 blade at 17 pitch would help but perhaps I'd still be below the cruising rpm range that I'd consider efficient at 4200/4400

Theory of 2" pitch = 400 rpm change.

So, would I be better with the 15" pitch? Numerically it would seem appropriate for fuel consumption range, comfort, and power. Plus get me down to a better manuvering / trolling speed to boot.

Something inside my head says 16 pitch would be perfect,, but them little voices keep getting me into trouble.

Any thoughts on this?

Re: thoughts on prop change (help please)

What motor do you have ?

Re: thoughts on prop change (help please)

130 hp Yamaha 2 stroke.

Re: thoughts on prop change (help please)

Float, welcome to Iboats prop forum and we will try to help you as much as we can but without more information no one can help you, and I will tell you I need more information than anyone else. But if you would like my help fill this form out and I will help you as much as I can, if you would prefer to not go to this much trouble there are other people who will help you.

Iboats Boat and Motor Info
1. Year, make and model of boat
2. Length, width and base weight of boat, look for boat decal on back of boat
2a.What is the recommended HP for your boat
3. Number of people and gallons of gas normally on boat
4. What do you use the boat for
5. Is it a Deep Vee and if so how many degrees of deadrise
6. Year, make and model of motor
7. HP and gear ratio of motor IMPORTANT
If you don?t know the ratio, you need to pull the plugs out and put a piece of tape across the prop and the lower unit and then cut it between the prop and the housing and turn the motor until the tape lines up with each other, it is easier if two people do this, so one can watch the prop while the other counts the revolutions of the motor
8. Manufacturer?s recommended Wide Open Throttle (WOT) range
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
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
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 foregoing 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
19. If you are trying to attain a better cruising speed and fuel savings or trying to attain a faster speed I will want you to take your boat and run it with 1 or 2 people and give me the RPM and speed readings starting at 3,000 RPM in 500 RPM increments all the way to WOT.

REMEMBER, The numbers I give you will be NO better than the information you give me

The only thing I ask of you is to come back and give me a report of WOT RPM and speed for my database.

H

Re: thoughts on prop change (help please)

Ahhh for $100.00 id just run out and get the 15 sounds like you would be happy with that but im new to boating.

Re: thoughts on prop change (help please)

Not really sure where we're gonna get a (good) ss prop for 100.00.........

Anyway, rather than running out and spending $$ on a different / less pitch prop to simply gain rpm I'd start with looking at the set up. If the AV plate is below or even with the keel and the current prop is in good shape I'd start by raising the motor. That will reduce drag and improve overall efficiency.

Re: thoughts on prop change (help please)

since the OP is from a year ago - would think it is resolved?