prop suggestions

[miket]

I've got a 95 230wa with a 150 rude on a bracket. Engine runs good, fresh tune up, new fuel etc,. Engine height adjustments have not made much of a difference so I have it where it performs best with current prop. Currently I am only getting between 4800 - 4900 rpm wot. 34- 36 mph.
Prop is a 15 x 17 aluminum no name. Previous owner bought boat new and said the dealer worked through a few props to get it to plane better. My plan is to get motor propped for performance/economy and add trim tabs to help get on plane. Good idea or no? Any suggestions on props? 

Thanks

[acdaddy0]

Trim tabs are great idea , I have a small boat but love them tabs. Not a prop pro but less pitch is what you need. Looking at specs your boats not doing bad.tabs will get you on plane quicker. There's not numbers on the 230 . But seems they under powered it a bit.

[miket]

The Mercury calculator recommends 15 pitch but lists different diameters so I am lost on that.
Yeah it probably is underpowered but it is lightly used and I want it to last.

Thanks

[miket]

Hey SC thanks for the reply, I am definitely going stainless. I love WOT so you guessed wrong there
Looking at the Merc prop selector again it suggests different pitches for different props so IDK. I may try a 15 x 17 which is what I have now, I have read stainless may raise rpm's over same aluminum prop, or a 15 x 15. The BPR site suggests increasing pitch will lower rpm and lowering pitch raises rpm. I wish someone close had some I could try.
Once propped correctly and I pay off the new FF I just bought, tabs will be next.

[acdaddy0]

SC, wouldn't flexing prop lessen pitch and cause higher rpms? Smaller diameter sounds right. I'm no pro either. Asking this cause I'm running an aluminum prop as well, but less weight . Wish there were a loaner prop program or a try it before you buy it.

[miket]

According to my current #'s I am getting 18% slip.

[miket]

Oct 1, 2014 15:59:25 GMT -6 acdaddy0 said:

SC, wouldn't flexing prop lessen pitch and cause higher rpms? Smaller diameter sounds right. I'm no pro either. Asking this cause I'm running an aluminum prop as well, but less weight . Wish there were a loaner prop program or a try it before you buy it.

Prop Gods in Florida has a try and return but only for Florida residents I believe. I have heard of another one I will see if I can find the name.

[flintlock]

Ken at www.propgods.com is the man

[T-Topless]

If you're getting 34- 36 mph at 4800-4900 rpm WOT on a 23foot, 3,000lb (+motor, fuel and beer) deep vee boat, then more pitch is NOT what you need. I don't think you'll get much more speed from 150HP, but trim tabs will help level the boat and pick up 2-3knots.

If you must play with the prop then a good local prop shop will let you try a few if you agree to buy from them.

You won't see any speed difference from Stainless on that heavy boat (some actually lose speed because they lose flex. The flex lets them run more pitch but flexs under heavy load when coming "out of the hole" to reduce pitch for acceleration), but they're nicer and won't get bent as easy if you bump something.

Cheap way out is a Stainless Johninrude prop off Ebay...

[miket]

Thanks for all the replies.
I was kind of hoping someone out there was running the same setup but I don't think it was a popular one. I am within the recommended 4500 - 5500
Rpm range for the engine but on the low side.
I will be consulting the experts.

Thanks again

[Warpig]

I'll also confirm Ken at Prop Gods is the guy to go to. I'm in Ohio and he offered to send me a couple of demo props when I was looking to change mine. Subscribe to their forum and post on there.

[Warpig]

Warpig is the 19P Vensura prop what you ended up with after looking to reprop or is that what you started with and what diameter is that prop.

Read more: seaproforum.proboards.com/post/new/3607#ixzz3FSWdvktP

The Vensura is what I switched to. It's a 14 x 19 4 blade. I had a 15 1/2 x 17 Mirage 3 blade on there. The Mirage had a better hole shot but I was having trouble staying on plane when it got rough out on Lake Erie. I was always fiddling with the throttle trying to go fast enough to stay on plane but no so fast as to shake the boat to pieces. The Vensura has more bite and helps with that. Since I went up in pitch and down in diameter WOT RPM's stayed about the same. (I think they say estimate 250 RPM for every 2" of pitch either way and 250 RPM for each 1" of diameter either way.) I could do a little over 40 MPH with the Mirage. I can only get about 39 or so with the Vensura. Doesn't much matter because in my 206 I normally can't go anywhere near that fast on the big lake.

I think the best prop for what I was trying to do would have been the 17P Revolution 4, but I was trying to find a lightly used one since you never know how they are going to work until you try one. I ran into the Vensura for a good price first.

[gnrphil]

That's really interesting, I've read a lot about props but this is the first place I've read about the diameter difference. My theory has been confirmed by you guys, I was thinking the smaller diameter would allow the prop to turn easier(less surface area=less resistance??) Therefore going up too much on pitch would be helped by a smaller diameter. I'm currently running a 14x15 ss running 39mph at 5400rpm, going to try a 13 3/8 x 19 ballistic just for giggles as I got it cheap of ebay :-)

[gnrphil]

That didn't work, 30mph at 5500 rpm. 44% slip

[acdaddy0]

Gn , I thought the same thing about diameter . You saw my results with a POS prop. I think it's the rake which is unfamiliar to me as how to research. Gonna look into it.

[acdaddy0]

[gnrphil]

AC , I'm sure rake is a big factor also but most props don't have the rake stamped on them. plus that's gonna really fry my brain trying to work all that out :-)
Any way at least I figured a 13 3/8 is too small for me, need to find a 14 X 19 or 17 to try out or something close.

[acdaddy0]

Gnrphil, yeh that's what I meant about unfamiliar as the rake and blade surface area are not documented. A bigger surface area with the same pitch should mean more bite. A larger diameter means more bite and also greater prop speed at the tips. Small diameters are for light boats. And I think there is a difference in four stroke props verses two stroke props as far as blade surface area . I'm gonna do a slip test on my smaller diameter more pitch prop and see what happens. They only state high rake or progressive rake but no numbers. Hit or miss trying new props and expensive.

[gnrphil]

AC, Yeah it's hit or miss and can be expensive for sure, I only tried the smaller diameter because the prop was cheap. I was surprised how much difference less than an inch in diameter could make.

[acdaddy0]

I have had a prop on another boat that had bad hole shot but great top end. I researched and drilled my own vent holes in prop per instructions and locations , worked great.