115 E-TEC on a 1700 prop suggestions

[DougFunny]

Have been doing sea trials on a 14.75x18p and 14.75x16p Vipers.

The 18 at WOT and trimmed out was running me 5300-5400 rpm at 36mph and could barely get me out of the hole even with moving weight up to the bow.

The 16 was night and day difference out of the hole and was running me at about 5500-5600 rpm at 38mph. I'm getting close to where I need to be with this prop, but I'm still unhappy with the top speed. I know it's not a go-fast boat, but I expected a little more out of the 115 Evinrude E-TEC on the 1700.

Tests were run with close to a full tank of gas and about 500-600 pounds (people and gear). Engine is mounted at the highest setting, cavitation plate is a couple inches above the bottom of the transom.

I know it will probably be hard to find someone with this same set up, so I'd like to hear from those with 1801 hulls and what pitch prop you're running.

 

[Brent]

Which hole is it mounted?
You might need to adjust engine height first then move to prop selection

 

[DougFunny]

Which hole is it mounted?
You might need to adjust engine height first then move to prop selection

I have adjusted the engine height from my first couple tests and have found the best performance at the lowest hole on the engine mount, engine being at its highest setting.

 

[Brent]

If you have not read this article at
http://www.veradoclub.com/index.php?topic=137.0

It is a good read.

Others and Ken at PropGods will comment on prop

 

[jeffnick]

I played with about 12 props on my 1850 (18' Seaswirl Striper) w/ 115 E-Tec.
Here's size, speed in GPS MPH and RPM's for some 3 blade props:


Hustler 15X19 37.1 5300

Hustler 15X17 36.5 5400

SST 15X16 35.6 5600

Viper 14 3/4X17 37.2 5570

Rebel 15 3/4X15 35.5 5500

Piranha 15X17 30.5 5500

BRP 15X17 36 5500

BRP 15 1/2X15 33.5 5700

The factory Viper will get you the best top end, the Rebel the best control and fuel economy.

 

[Brent]

Is the top end speed loaded or light?

 

[jeffnick]

Is the top end speed loaded or light?

We only had one condition - cruise, that included ~30 gallons of gas, 10 water, a 6 gallon cooler full of beer, two people (but no dog back then). The rig weighed about 3800 lbs including the tandem axle trailer.

 

[BradH]

I have a '91 1700 with '06 Yamaha 115 V4, 13" diameter x 19" pitch 3 blade Powertech SCD (Yam painted stainless knockoff).

With 1-2 people light load and a clean bottom I can easily hit 44-45mph at 5300-5400 rpm. This is with the cav plate even with the bottom. I have since raised the engine up two holes to the highest position but have not run it yet. I am hoping for 47-48 mph and a lot more efficient cruise (currently about 3-3.5mpg at 25 mph).

Both of our engines are 1.7L V-4 two strokes with 2.0:1 ratios. My Yam weighs 360lbs, your Evinrude 390lbs. The engines are really close except that you can turn 6000rpm where I turn 5500.

Your numbers seem way off. You should be at least in the low 40s. I think you may have to much diameter (blade area in the water) although the higher engine may negate some of this. I don't think the engine has the torque to turn this much propeller.

Try a 13" diameter wheel in 18" or 20" pitch. I would like to see the RPMs up to 5800-5900 loaded as you describe. The bottom has some hook in it so go for a more bow-lifting prop (more rake and/or cup).

Post some pics of your setup if you can. I will update when I (finally) get back in the water.

 

[DougFunny]

I have a '91 1700 with '06 Yamaha 115 V4, 13" diameter x 19" pitch 3 blade Powertech SCD (Yam painted stainless knockoff).

With 1-2 people light load and a clean bottom I can easily hit 44-45mph at 5300-5400 rpm. This is with the cav plate even with the bottom. I have since raised the engine up two holes to the highest position but have not run it yet. I am hoping for 47-48 mph and a lot more efficient cruise (currently about 3-3.5mpg at 25 mph).

Both of our engines are 1.7L V-4 two strokes with 2.0:1 ratios. My Yam weighs 360lbs, your Evinrude 390lbs. The engines are really close except that you can turn 6000rpm where I turn 5500.

Your numbers seem way off. You should be at least in the low 40s. I think you may have to much diameter (blade area in the water) although the higher engine may negate some of this. I don't think the engine has the torque to turn this much propeller.

Try a 13" diameter wheel in 18" or 20" pitch. I would like to see the RPMs up to 5800-5900 loaded as you describe. The bottom has some hook in it so go for a more bow-lifting prop (more rake and/or cup).

Post some pics of your setup if you can. I will update when I (finally) get back in the water.

Those top speed numbers are great. I have the 25" shaft V6 gearcase 115 which gives me a 2.25:1 ratio.

All of the following numbers were done with 2 people and a full tank (40 gallons) of fuel.

Since I've posted I've tried a few other props and ended up for now settling with a 15.75x15p Evinrude Rebel that I found cheap on Craigslist. This prop is getting me around 5800rpm @ 37mph. Cruising speeds are comfortable and prop does a pretty good job at keeping plane at lower speeds. I'm not sure if you encounter this problem, but taking tighter turns while planed the aft end will wash out. My only guess to why this happens is because of the flat bottom hull design in the back. I plan on dropping the engine 1 hole to see if this helps mitigate this.

By far my favorite so far was a four blade 14.25x17p Evinrude Cyclone. WOT gave me around 5700rpm @ 43mph. The four blade also gave the boat a lot more bite through in the water as well.

I will keep an eye out for higher pitch, smaller diameter props that I can try out to see how those work, but because my 115 has a V6 gear case, the smaller diameter props are hard to come by/non-existent.

 

[BradH]

By far my favorite so far was a four blade 14.25x17p Evinrude Cyclone. WOT gave me around 5700rpm @ 43mph. The four blade also gave the boat a lot more bite through in the water as well.

With a 2.25 ratio this setup yields -5% slip. Something is not right here, are you positive the ratio is 2.25 and it's 17 pitch? Even though it's stamped 17 it might be closer to 19" effective pitch.
http://www.mercuryracing.com/prop-slip-calculator/

I still think there is more to be gained here. Are you willing to work with a propeller guy? They may know of other propellers or be able to take a larger diameter wheel and cut down the diameter and/or blade area. I trust Brett at bblades.

The boat does cavitate in turns similar to what you mention, I attribute that to my cav plate being too low catching water and a propeller with little to no cup. I don't think it can grab or bite the water enough.

I am hopefully launching on Saturday and will update if I get some numbers.

 

[BradH]

Finally went out and ran the boat. Was rough out so I could only get it up to about 30 mph or so.

Overall boat is much better to drive, doesn't feel like I'm dragging a 2x4 behind it now. Still slides a little and cavitates in hard turns.

3200 rpm, 23 mph = 10.7~ slip.

I really need a different propeller.