18' 130HP BOAT PROP

[vipertblck]

'01 chapparal 180SSE 4 cyl 3.0L with alpha 1 outdrive(Actually an aftermarket sei outdrive). has a factory looking 3 blade on it, pretty banged up. marina told me to put a 4 blade 19 pitch on it. current prop only gets it's to MAYBE 35mph with 1 person aboard and no gear. does the suggested prop sound right? also where can I find them?

 

[Maclin]

A 4 blade 18p is probably more like what you want.

 

[vipertblck]

would this get me to a little over 40mph?

 

[Scott Danforth]

would this get me to a little over 40mph?

only if you are running max RPM at WOT

However I go back to the basics in the Prop sticky http://forums.iboats.com/forum/gene...p-questions-and-topics/295058-read-this-first

When posting a question about propellers, you cannot get a reasonable answer unless you provide the following information in your post: Items 1-4 are essential for meaningful response to most questions.
1) Performance issue you are trying to correct.
2) Current prop manufacturer, model, aluminum or stainless as a minimum.
3) Current prop diameter and pitch (required).
4) Wide open throttle RPM and speed with an average load (very helpful)
5) Engine/drive make, model, year, and HP
6) Boat make model, year, length and weight

you provided us only some of the data.

Also, a good marina would have test props for you to dial your boat in.

 

[vipertblck]

I've never driven boat. Bought with cracked block, had marina install new engine, and they took it on water to trial run after the job. Said it did between 30-35 mph at about 4000rpm according to gps. I was talking with a local prop shop and they told me my prop on there now is a solas aluminum 13 or 15(I forgot which) 3 blade. On the prop is says solas 15.5X13 He loaned me an old 3 blade 19 I'm gonna try and take out this weekend to try out. Mercruiser 3.0 4 cyl with SEI SSE116 outdrive. boat is 2001 chaparral 180SSE

 

[steelespike]

Is the motor new or "good" used or factory rebuilt? It's worrisome that it only reached 4000 at 30-35. with a 13" prop.
Actually a 13" prop would only make about 21 mph. @ 4000 would have too make over 6000 to do 35.
If it truly made only 4000 with a 13" a 19" will be much worse.Hopefully the tach was way off low
Do you know the gear ratio of the out drive it may be on the outdrive somewhere. usually a 3.0 would have something like 2.00:1.
You should varify your tach is accurate.Have them check it with sa shop tach.
A fresh 3.0 should usually run a 19" or 21" pitch at a wot speed of about 40.

 

[vipertblck]

Motor was a new motor according to dealer, not a reman/recondition. Anyway I think there may be more problems now. I put an old 19 on it that a prop shop gave me to try out, took it out and was just under 4000, at like 35mph according to my gauges. Then when I pushed it a little more to around 4000-4200, it lost it all. By lost it all I mean acted like a manual trans where your movin along and then just push the clutch in and the engine rpm's raise. First thought was coupler, but when I backed throttle down and hit it again, we moved along just fine?? The prop that the marina had is NOT the prop that was on the boat today when the problem demonstrated itself. The solas 15.5x13 is what was on and what the marina had when they test drove after the engine install. Marina said nothing about the boat doing this. My question for all of you is....could the prop I installed on the boat cause this problem? One thing I noticed is it's much smaller than the solas one (overall diameter wise).

 

[steelespike]

Your description is a little difficult to follow. Your saying the Solas 15.5 X 13 lost it(motor revved but boat slowed?
Usually as pitch increases diameter decreases. Especially with a 6" difference.The usual I/O prop is 14" diameter or more.
Usually a prop under 14" would be suspected to be for a smaller outboard.There may new exceptions a 4 blade,high pitch
specialty props.
Sometimes a hub will slip.you can check by putting a water proof line across the hub and body make to "loses it" and then check to see if the line is broken.

 

[vipertblck]

Your description is a little difficult to follow. Your saying the Solas 15.5 X 13 lost it(motor revved but boat slowed?
Usually as pitch increases diameter decreases. Especially with a 6" difference.The usual I/O prop is 14" diameter or more.
Usually a prop under 14" would be suspected to be for a smaller outboard.There may new exceptions a 4 blade,high pitch
specialty props.
Sometimes a hub will slip.you can check by putting a water proof line across the hub and body make to "loses it" and then check to see if the line is broken.

No, the solas 15.5X13 prop is the one the marina water tested it with and they said nothing about this issue, so I'm assuming it was not there?! Then, the 1st time I took it out myself, I put a different prop on beforehand (the old 19) and it demonstrated this issue I described. I think I'm gonna put the original solas prop back on it and see what it does?!

 

[walleyehed]

vipertblk, what altitude are you operating at?

 

[vipertblck]

vipertblk, what altitude are you operating at?

Not too sure on that, I'm in northern Illinois. Suburbs of Chicago

 

[walleyehed]

OK, just wondering about some other possible influences... Not an issue where you are. I would find out what the deal is with the hub on the prop that cut loose and see if it checks good first then we'll take another look. as mentioned above, the numbers don't pan out.

 

[vipertblck]

Well I put the original solas 15.5X13 back on the boat yesterday and ran it. MUCH slower on the speedo gauge aboard but I touched 4000.....then up to 4500...and it held. so am I safe to assume my coupler is ok?

 

[Tail_Gunner]

Before you do anymore testing find the gear ratio on the drive and post it...if you can.... your marina sounds like a zoo of bilge monkey's....there now I said and feel a bit better. to bring this down to earth you really need to know the gear ratio and 13p prop is foolish on that kind of rig

 

[vipertblck]

I know it's not an actual Mercruiser outdrive, it's an SEI one, SE116 it says on the sides. Does that help?

 

[steelespike]

If it doesn't slip with the 13"the coupler appears to be ok.
Near as I can tell a SE116 is available in a number of ratios.
Your needs to be around a 2.00:1 It may be stamped on the leg somewhere.
Ask the marina what ratio and where it is marked.
If we had your accurate speed at 4500 we can estimate the ratio but only as accurate as the numbers you give us.
To struggle so with a 13" pitch either the motor is no good or it is the wrong ratio. Your 3.0 would normally have something like 2.00 or 1.98:1
that means the motor turns about twice as the prop turns once.
You can manually check the ratio by removing the plugs and turn the motor by hand carefully count the revolutions to turn the prop once.