Thru-Hub vs. Over-Hub props?

[imq707s]

I've always ran my 27 DAH SRX on my Vegas, but I just recently picked up a 24p Raker (with tons of cup). Although the SRX is a few mph faster on the top end, the Raker seems to be much smoother and holds the bow up better when ever I get into some big lake rollers. I also noticed that at cruising rpms (30000-4500) the Raker runs faster at the same rpm than my SRX. The Raker had much less wheel torque also.

Is that pretty common when comparing any thru-hub prop to an over the hub type prop, or just when comparing an SRX to a Raker?

The only thing I didn't like abouut the Raker was that when I was running wide open, the boat really felt loose and wanted to chinewalk...I really had to drive the thing to keep it balanced on the pad. With the SRX, it's much easier to drive.

:D

[pyro]

Chinewalk? You're just giving the raker more trim than it needs, no big deal. An extra-cupped raker on a boat with 10" setback is the formula for major huge bow lift. Did you see the pictures I posted in my "flat attitude" thread?

Over-hub props tend to slip more at lower cruising speeds, especially at higher jackplate heights. On my boat, I have to get over 50-55 mph before I really get an efficient bite. Lowering my hydraulic plate lowers the slip % and decreases steering torque at cruising speeds.

The slip usuallyis accompanied by little extra roost spray off the blades. As you may recall seeing in the "Disturbed" video with Helmut's STV, as he slowly accelerates alongside the chase boat, the rooster tail dies off as he approaches 60-80 mph speeds.

Over-hubs were meant to go fast, that's a fact. I'm mad at myself for ever selling my 26p trophy, I'm going to get ahold of another 25 or 26 pitch thru-hub prop soon for general use, maybe a Tempest plus or a Raker...

-Chad

[staylor]

I ran both an SRX and a Raker on my previous rig with the same experience as you. On my current rig I don't go fast enough for a chopper but I've played with a Raker, a Tempest, and a Trophy. The Tempest seems to hook up a bit better than the Raker, probably due to it's bigger blades. The Trophy hooks up the worst but is the easiest handling of the three. The Tempest is the fastest, about 1-2 mph quicker than the other two.

[Steven]

how high did you run the raker and do you use a cone? thanks:)

[pyro]

I have a 26p Tempest Plus on the way. We'll see how it runs when it gets here.

[imq707s]

The propshaft is set 1" under the pad. Yes, I've got a land & Sea nosecone. I've tried going higher but I start getting a bunch of slip at cruising speeds, and no top end increase. If I go any lower, it wants to chinewalk pretty bad. 1" under the pad seems to be a pretty good height for my boat/setup.

[B.Mac]

Originally posted by pyro
I have a 26p Tempest Plus on the way. We'll see how it runs when it gets here.

Get ready for the ride of your life Pyro:D You may have to get her worked up a little but wait 'till you feel how that hull packs air now!!! Get the Tempest plus and run huge vent plugs so she'll break loose..... If it's too hard to turn you can get the leading edge cut slightly to pick up RPM w/o dropping MPH
You'll love that prop.....experiment with it!!!It's scary fast!!:eek: What kinda HP has that Blackmota got? I would guesstimate 77-78 @ 6500 RPM right outta the box. Tweak her out to a 27 pos a 28 if you can spin it.....I believe you can spin a 27+ @ 82+


Originally posted by imq707s

The only thing I didn't like abouut the Raker was that when I was running wide open, the boat really felt loose and wanted to chinewalk ...I really had to drive the thing to keep it balanced on the pad. With the SRX, it's much easier to drive.:D

Get some seat time with that "loose" prop, I bet it'll beat any others you've run once you learn to drive it.....also try not to run alot of positive trim.......it seems like I get trim happy too when trying to squeeze out a few more MPH but after 75 MPH you need to be trimming neutral to negative with the correct setup.....
B.MAC:D

[imq707s]

I'm planning on heading down to the lake this weekend and hooking up with Randy (AQUAhollic) to test out a few of his props that he has. I can't wait to run that Raker with just me in the boat. It's a 24p, but it runs like a 26 or 27 because of all of the cup someone put in it. Randy thinks that taking some of the cup out might get the boat to run a little faster. It sure is nice having a friend that is a prop guru:D

[imq707s]

Here is a closeup of that blade.