1986 Celebrity 18'....Best prop for cruising?

[chevy-aholic]

Hey there,
looking to re-prop my Celebrity 180 (18', 190 HP mercruiser inboard) and I'm wondering what the best one is out there for cruising/speed. I do a ton of wakeboarding with this boat also, so I don't want to hurt the acceleration too much, but it's kinda lame that it'll only pull 35MPH with only 3 people on board. Here are the current specs:

Motor: 3.7L Mercruiser 190HP
Outdrive (if it matters): Alpha 1
Current prop: 14 x 19 Merc. (alluminum)
Current WOT RPM: 3900
Current Top Speed: 33-35MPH (approx. 550lbs on board)

I've been looking alot into stainless props, mostly because the lakes around me are extremely murky. Almost every time out we will run thru a sand-bar or hit some underwater lumber in the middle of the lake and not even see it (most lakes around here are only 10-15 feet deep) so I'm hoping a stainless prop would be a little more "resiliant"

thanks

 

[NoKlu]

Re: 1986 Celebrity 18'....Best prop for cruising?

The harder stainless prop will transfer the shock of the lumber up to the drive instead of absorbing it with the aluminum and they are a lot more expensive to replace. It sounds like you need some kind of gps/depthsounder set up so you can plot the shallows on a gps and know where they are next time out. The gps will pay for itself by saving you money on props.

 

[hwsiii]

Re: 1986 Celebrity 18'....Best prop for cruising?

Chevy, how many people in the boat at 3,900 RPM. and what is RPM and speed with one person in the boat.


H

 

[chevy-aholic]

Re: 1986 Celebrity 18'....Best prop for cruising?

The harder stainless prop will transfer the shock of the lumber up to the drive instead of absorbing it with the aluminum and they are a lot more expensive to replace. It sounds like you need some kind of gps/depthsounder set up so you can plot the shallows on a gps and know where they are next time out. The gps will pay for itself by saving you money on props.

That was my first idea, but the lakes around us are sooooo crowded that we have to weave around quite a bit and never really run the same course twice. I also havn't found a good depthfinder that's work at speed, but I'm sure there's one out there.

 

[chevy-aholic]

Re: 1986 Celebrity 18'....Best prop for cruising?

Chevy, how many people in the boat at 3,900 RPM. and what is RPM and speed with one person in the boat.


H

3,900 is the RPM with 3 people in it. Runnin' solo I can get 4100 and 35 MPH out of it. I just can't go more than 35 and I think this boat should be able to pretty easily. I've been told that even tho it's revving higher, it's not going to go any faster cause alluminum props have to much flex. I've been told to look into stainless cause they are more efficient and will shoot out of the hole quicker. Any truth to this?

 

[hwsiii]

Re: 1986 Celebrity 18'....Best prop for cruising?

If your gear ratio is 1.71:1, you can drop 2" of pitch and you will gain right at 500 RPM at WOT. At the speeds you are going the flex in an aluminum prop is negligible, the reason SS props normally do better is the blade geometry built in to them, not because of the flex in aluminum props. Your hole shot and acceleration will increase and you will be able to feel it and see it pulling people behind the boat.


H

 

[chevy-aholic]

Re: 1986 Celebrity 18'....Best prop for cruising?

ok, then it sounds like that's just as fast as this hull can be pushed thru the water. Does the SS prop hurt top speed at all. The reason I'm considering it is because my current prop is getting pretty ragged, and I'll be switching soon anyways. If I could get better performance while towing and have the same or slightly higher top speed, then I would deem it worthwile.

 

[hwsiii]

Re: 1986 Celebrity 18'....Best prop for cruising?

A SS prop will normally give you a better top end speed than an aluminum, you just have to get the right SS prop that is designed for your hull form, motor and uses.


H

 

[chevy-aholic]

Re: 1986 Celebrity 18'....Best prop for cruising?

What would you recommend for a good stainless prop? I got a 14" on there now, and the stock was a 14 1/2". What pitch would you go with?

 

[hwsiii]

Re: 1986 Celebrity 18'....Best prop for cruising?

Those numbers just don't sound right to me, get this information for me and i will do a complete analysis, i think you should be going faster.
Working over the internet and not being able to see the boat or prop the question is about makes it much harder to propose a solution to the correct prop that you need, and most people don?t know the make and model of the prop . When we get information in bits and pieces we continually have to look back and forth to try and piece the information together. The following form has all of the information that is needed to help you with your problems in finding the right prop. If you do not know all of the information that is asked for on the form please give us the most information you have available as I have a program I designed to find the right prop for any planing hull boat that needs this information. It requires time to find all this information when we have to look for it and in my defense I expect you to be willing to expend as much effort in finding the right prop as I do. We hope to be able to help you get the best prop we can for your particular uses, and this information is required to do that. There are other people who can help you that don?t need this much information, if you would rather wait for them just don?t fill out the information I am requesting.
It is not as simple to pick the right prop as most people coming to this forum think it is, that is why we ask so many questions, it is for your benefit we ask all these questions. And if you have a stainless steel prop or are changing to one the blade geometry of the prop can make a lot of difference in speed and RPM. Most of my calculations are done assuming an aluminum 3 bladed prop will be used, when changing to a SS prop or changing within SS props we need to discuss what you are trying to accomplish.

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
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
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
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 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 much higher elevation
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

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