[whoislang]

Talked to Michelle at Powertech and this is what she recommended for my rig:

RED 3 17, best bet for two stroke

SCD 3 17, comparable but usually she puts them on 70 four strokes

NRS 3 17 could be super fast

Anyone run a power tech in these models in or near Charleston SC? Would like to get some testing done in order to know which prop I should get. Any help would be appreciated but would like it if someone would let me throw on their prop and get some performance numbers before I buy.

Thanks

Needs to fit Yamaha 70 2stroke.
Boat is a Beavertail B2.

 

[NealXB2003]

I think the rpms between the RED3 and the scd3 will be miles apart if the pitch is the same. Granted, my 70 is a 4 stroke. But I usually run a 16 scd3 at 6350 rpms. I have a 13 pitch RED3 and it'll usually pull about 6250 rpms. It's got more cup and it's much harder to turn. Red3 does have more bow lift, if your boat likes bow lift. Scd is a stern lifter.

 

[NealXB2003]

PS.... if you really can turn a 17", a Yamaha black stainless like the one I posted for sale yesterday would be a good option. The fast duck boat crowd claims they're 2-3mph faster than the SCD3 (which is a copy of the Yamaha prop) and they'll retain bite higher on the jackplate. I didn't have the power to turn it to really see what it would do, but I can vouch that it doesn't ventilate as much as an SCD3 Even at 1"+ higher on the jackplate. Pushed my slug 38 mph, but I could only get 5800 rpms out of it. On a lighter boat, I have no doubt it would run 40. Wish you were closer.... I'd let you give it a run.

 

[whoislang]

PS.... if you really can turn a 17", a Yamaha black stainless like the one I posted for sale yesterday would be a good option. The fast duck boat crowd claims they're 2-3mph faster than the SCD3 (which is a copy of the Yamaha prop) and they'll retain bite higher on the jackplate. I didn't have the power to turn it to really see what it would do, but I can vouch that it doesn't ventilate as much as an SCD3 Even at 1"+ higher on the jackplate. Pushed my slug 38 mph, but I could only get 5800 rpms out of it. On a lighter boat, I have no doubt it would run 40. Wish you were closer.... I'd let you give it a run.

What boat are you running the Yamaha black on?

 

[NealXB2003]

I've got an 18' aluminum Excel. It's a .125ga hull that weighs in excess of 600 lbs. Not exactly a performance craft.

 

[NativeBone]

Talked to Michelle at Powertech and this is what she recommended for my rig:

RED 3 17, best bet for two stroke

SCD 3 17, comparable but usually she puts them on 70 four strokes

NRS 3 17 could be super fast

Anyone run a power tech in these models in or near Charleston SC? Would like to get some testing done in order to know which prop I should get. Any help would be appreciated but would like it if someone would let me throw on their prop and get some performance numbers before I buy.

Thanks

Needs to fit Yamaha 70 2stroke.
Boat is a Beavertail B2.

I have ran all three on my 70 2s. Wasn't thrilled with the Red or SCD models. Hole shot and turning was an issue.
I currently run the NRS model and satisfied with the performance. Good hole shot and turning. The NRS has more cup than the RED series.

I do not run a jackplate and motor cavitation plate is set 1-1.25" from bottom.
Cruise @ 33mph @ 5000rpm. WOT 38-39mph @ 5800rpm. Hope that helps.

 

[NealXB2003]

Hole shot and turning was an issue.

I had to have my prop guy add cup to my SCD3 to give it bite in turns.

RED3 had too much bow lift for a flat bottom (induced porpoise) but may be the ticket for a pad v.

 

[whoislang]

I have ran all three on my 70 2s. Wasn't thrilled with the Red or SCD models. Hole shot and turning was an issue.
I currently run the NRS model and satisfied with the performance. Good hole shot and turning. The NRS has more cup than the RED series.

I do not run a jackplate and motor cavitation plate is set 1-1.25" from bottom.
Cruise @ 33mph @ 5000rpm. WOT 38-39mph @ 5800rpm. Hope that helps.

What boat ?

 

[whoislang]

Found a SCD3 16p locally for 250. Figured it’s a pretty good deal so I’ll try it

 

[NativeBone]

What boat ?

Copperhead

 

[whoislang]

So, I tried out the SCD 16p last night.

Here's my notes

SCD 3 Blade 16" pitch 13" diameter

2 people on board, 10gal fuel, flood tide load (12 pack, 1 rod, one flybox)
6000rpm 37.3mph = 4% slip rev limiter
5600rpm 34.9mph = 4% slip
4700rpm 29.2mph = 4% slip
2000rpm 6.56mph = 50% slip

Hole shot seemed better, but didn't get a great feel for it yet.
---------------------------------------------------------------------------
Compared to
---------------------------------------------------------------------------

Chewed up Quiksilver aluminum QA2036x

3 blade 17" pitch 13.25" diameter

2ppl on board 15gal fuel, tarpon load (6 rods, full 20qt soft cooler, camera gear, food, tackle boxes and misc weights)

4300rpm 30.3mph = -2% slip
4300rpm 29.6mph = 0% slip
1700rpm 6.5mph = 45% slip

No Gear, one person

5800rpm 38mph = 5% slip


So, the questions I have are:

1. What gives with the aluminum prop calculating negative slip?

2. The SCD was all over the rev limiter at 6000-6100 rpm, and then the tach was acting weird, reading random values all over from 0rpm -4500rpm.

3. Could I bring the RPM down by going up to a 17" pitch SCD and gain some mph?

4. Is it safe to be able to get that high of RPM on my two stroke? I didn't even have the throttle pinned to the dash. More like 7/8 of the way down.



I will try the SCD again tonight by myself to try to see if my top end gets better with one less person and also test hole shot.

 

[NealXB2003]

What kind of tach do you have? Tiny tach with a wire wrapped around a spark plug wire? Mine gives crazy readings when I get into the rev limiter, because the spark is cut by tube computer.

 

[DBStoots]

How do you measure the prop slip?

 

[NativeBone]

How do you measure the prop slip?

Here is one way....

BBLADES - Prop Slip Calculator

OR

https://www.getaprop.com/blog/propeller%20slip,%20boat,%20horsepower,%20rpm,%20blade,%20slip,%20gear,%20ratio

 

[DBStoots]

Here is one way....

BBLADES - Prop Slip Calculator

OR

https://www.getaprop.com/blog/propeller%20slip,%20boat,%20horsepower,%20rpm,%20blade,%20slip,%20gear,%20ratio

Thank you!

 

[DBStoots]

Learned this today also:

Prop Slip. Slip is the difference between actual and theoretical travel through the water. For example, if a 10-inch pitch prop actually advances 8-1/2 inches per revolution through water, it is said to have 15-percent slip (8-1/2 inches is 85% of 10-inches).

What is normal prop slip? The number we will find is the difference between the theoretical and the actual boat speed, which is actually the slip value of our propeller if we convert it into a percentage. We should know that, as far as the ribs are concerned, most ideal slippercentages range between 4-8%.

 

[whoislang]

What kind of tach do you have? Tiny tach with a wire wrapped around a spark plug wire? Mine gives crazy readings when I get into the rev limiter, because the spark is cut by tube computer.

No, it’s a Yamaha 6y5 gauge

 

[whoislang]

PS.... if you really can turn a 17", a Yamaha black stainless like the one I posted for sale yesterday would be a good option. The fast duck boat crowd claims they're 2-3mph faster than the SCD3 (which is a copy of the Yamaha prop) and they'll retain bite higher on the jackplate. I didn't have the power to turn it to really see what it would do, but I can vouch that it doesn't ventilate as much as an SCD3 Even at 1"+ higher on the jackplate. Pushed my slug 38 mph, but I could only get 5800 rpms out of it. On a lighter boat, I have no doubt it would run 40. Wish you were closer.... I'd let you give it a run.

Just threw on a 17” SCD after trying the 16” and getting into the rev limiter. Will update this thread tomrorow hopefully

 

[No Bait / Lures Only]

Talked to Michelle at Powertech and this is what she recommended for my rig:

RED 3 17, best bet for two stroke

SCD 3 17, comparable but usually she puts them on 70 four strokes

NRS 3 17 could be super fast

Anyone run a power tech in these models in or near Charleston SC? Would like to get some testing done in order to know which prop I should get. Any help would be appreciated but would like it if someone would let me throw on their prop and get some performance numbers before I buy.

Thanks

Needs to fit Yamaha 70 2stroke.
Boat is a Beavertail B2.

Get the black yamaha ss prop

 

[whoislang]

Get the black yamaha ss prop

Running a 17p RED that somebody ported out, maybe 1/4" holes behind the base of the blades. Runs nicely on top end, 37-38 at 5300 with two people. Maybe the 16p RED would be the ticket. The 17p SCD was too slippy I think.