# Ported Props



## baconegg&cheese (Dec 27, 2017)

Got a new prop for better holeshot with my Yamaha F70 a few months ago, but plan on having the old prop re-tuned and keeping it as a backup/high speed prop. Thinking about having the old one ported, but am not sure how that will affect performance. Does anyone have much experience with running a ported prop or know how it would affect holeshot, cruising, top end, etc.?


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## Smackdaddy53 (Dec 31, 2012)

baconegg&cheese said:


> Got a new prop for better holeshot with my Yamaha F70 a few months ago, but plan on having the old prop re-tuned and keeping it as a backup/high speed prop. Thinking about having the old one ported, but am not sure how that will affect performance. Does anyone have much experience with running a ported prop or know how it would affect holeshot, cruising, top end, etc.?


I never understood why porting props was a thing. Supposedly the idea was to increase hole shot… The exhaust exits the ports and causes the prop to artificially lose grip like it’s blowing out. This will increase RPM and cause a loss of thrust which means decreased efficiency. If you get the correct prop for your skiff you won’t need porting. Just my opinion.


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## baconegg&cheese (Dec 27, 2017)

@Smackdaddy53 That's kind of what I was thinking. Right now the thing definitely bogs down before jumping on plane so I would think the higher RPMs would help, but if the prop is just blowing out then that would defeat the purpose.


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## NealXB2003 (Jun 8, 2020)

If they're drilled to accept pvs plugs, you can tune the holeshot. An appropriate amount of slip will let the motor spin into the power band but not blow out. The holes seal off once on plane and do nothing from that point forward.


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## NealXB2003 (Jun 8, 2020)

It's more useful when propping for top end, running a high pitched prop that might not otherwise get on plane satisfactorily. 

Not much sense in propping a skiff that way, because they're not going to be speed demons anyway with 40-60 hp.


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## finbully (Jan 26, 2013)

I’ve thought it allows for a faster spin up to get more torque, sooner for a faster hole shot. But I’m no expert. I have a 21’ Ranger bass boat with a 250 2 stroke Optimax. I have a 4 blade Fury prop that is ported and I leave all of the ports open. I get up on plane fine for my use and faster than the 3 blade Fury (also ported) that came on the boat. Both of my Mavericks (115 Yamahas, 18 HPXSs) have had 4 blade PowerTec ported props from the start and also work fine for me. I don’t obsess about top speed on either boat.


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## NealXB2003 (Jun 8, 2020)

That's exactly what it does. Too many holes and it'll blow out, though. 


Plug the holes on your ranger and I bet hole shot suffers. At least with a load.

On the smaller boat/motor, I doubt you would see as much effect from the same test. Less torque to break the prop free, less exhaust gases passing thru, e.t.c.


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## attitudeindicator (Sep 8, 2020)

NealXB2003 said:


> If they're drilled to accept pvs plugs, you can tune the holeshot. An appropriate amount of slip will let the motor spin into the power band but not blow out. The holes seal off once on plane and do nothing from that point forward.


👆🏼This… I ported my prop for my F70 when I had one. Saw an improvement. As you move forward the exhaust stops exiting the holes and goes through the hub.


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## ek02 (May 8, 2012)

2006 16' vacuum bagged Super Skiff with a 90 HP 2 stroke. All 3 of my props are ported. The hole shot has always been great on this and my old 1994 Super Skiff. I ported a prop myself on an old Starcraft I had with a 70 Evinrude and it made a big difference on the hole shot.


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## hipshot (Sep 29, 2018)

There is a huge difference between prop dynamics for a (relatively) heavy pad-vee hull (bass boat) and a poling skiff. The hull on the new 18’ skiff I have coming weighs less than 1/7 what the hull weighed on my 18’-7” bass boat. The bass boat sported a 175 on a jack plate (moving the fore / aft center of gravity back); the new skiff will run a 30. The bass boat had 17 degrees of deadrise and a pad, as well as a prop with a larger diameter and pitch. The skiff will have 2 degrees of deadrise and a tunnel, and a prop with a much smaller diameter and pitch. Additionally, the bass boat’s props had a lot of rake to help hold the bow up; the skiff doesn’t need bow lift. And that V6 175 had a lot more torque than a inline 3 cylinder 30. Obviously, several very significant differences. I ran a couple of vented props on the pad-vee hull; they definitely improved hole shot. 

The way vented props function, part of the exhaust gases flow out of the vents ahead of the blades at low RPM, creating temporary cavitation. This allows the prop to spin up faster; the increased torque at higher RPM is needed to get that heavy hull (which is pushing a lot of water) moving. As the prop spins faster less of the exhaust gases are able to escape through the vents; the path of least resistance follows the force of the flow straight out the hub. When the prop is spinning fast enough to hold the bass boat up on plane all of the exhaust gases are exiting through the hub.

Never having run a vented prop on a poling skiff, I can’t say for certain that it wouldn’t enhance the hole shot. But a properly powered and balanced poling skiff with trim tabs will generally have a hole shot that boggles the mind of a bass boater, without venting the prop.


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