PVS Holes

[Jon]

The forum won't let you search for 3 letter words, so I can't look for PVS... and PVS holes returns nothing. I'm sure it's been brought up before, but I can't find anything so far.

That being said, I have a 27 Trophy Plus with 4 PVS holes. I understand their purpose, but mine are totally closed off. When I nail it out of the hole, maybe it bogs a little, then it totally blows out and I have to let out of it. I imagine if I replaced the solid plug with a partial plug or even open, that it would rev better down low, but still blow out. I also read that they're not supposed to affect anything but low RPM and basically the holes seal at some point because of water pressure.

What do you think? And I assume I could find some plugs somewhere and just see what happens, which I will likely do. Are they just a gimmick though?

https://mercurymarine-gsdesign1.netdna-ssl.com/media/filer_public/81/a4/81a4aef2-f0f5-4604-a183-d5d2cec22ea8/performance_vent_system.pdf

 

[mittenbass]

They are not a gimmick but they won't solve all holeshot issues by themselves. If you are bogging at first they will help that, however it will still break loose when the bow comes down. Your best bet to cure that is to have the prop worked. Some added cup in the tips will help the prop stay hooked up. Too much cup however will cause ill handling on our Allison's at wot because there will be too much bowlift. It's a delicate balance so send it to a prop guy who knows Allisons.

 

[Jon]

I saw somewhere that a person suggested just buying a set of blank plugs and drilling them little by little until you achieve the best fit, and if you go too far, just have a second set of plugs ready to go back to... so I may try that.

As far as the cup, the prop is a 27 trophy with an allison cut worked by the guys in Soddy Daisy. I think the cup is aggressive already. I'm going to add both the skid planer and the plate on the planing plate on the LU as well. I'm wondering if I can find a balance then? Sorry for not providing the info on the prop work in the original post.

Thanks for info and confirmation that they're worth messing with.

 

[harrells]

Try popping out 1 or 2 plugs and test run. Could be motor is too high causing it to spin up when the bow breaks over.

 

[whipper]

Try popping out 1 or 2 plugs and test run. Could be motor is too high causing it to spin up when the bow breaks over.

i never ran plugs in my trophy's at all. Could be as Harrels says. Its not just spinning up then grabbing? I would pop all of them out or try a differant prop. My old 27 trophy would spin up when taking of them grab and go. Just the nature of the beast. I never run a trophy past 1/4 below because surfaced any higher they dont last as long. 1/4 to 3/4 below triple checked you are that high try not letting off the gas and when she starts to lay over start trimming up. I start take off a couple bumps up never right down on the trim. that way Im a head of the game as she lays over. Some props are ment to spin up before they grap. Kinda like a sling shot effect. its normal for some to spin to 5000 rpm then grab dropping the rpm to 3000 or so then your off. Takes a few bumps to keep the bow from digging in then a couple more to 65. Then a few more to top speed or so. My 27 trophy acted that way. my 25 with no holes filled hardly brakes the water at all. My 27 broke the water lots in comparison. {spun up} the higher pitch you run the more this is normalish.:big grin

 

[Jon]

It definitely could be spinning then grabbing... for some reason I've let off the trottle as it starts to slip as I've never had that be a good thing on other props in the past. Next time I get out, I'm just going to let it eat and see what happens.

So for hole shot, nail it (not trimmed to the stop completely), and as it lays over start to come up. Motor 1/4 to 3/4 below.

You guys are on it with things to try. I wish it would warm up a little. Thanks for all the suggestions.


I'm going to try some different LU's soon. A buddy has a few with different setups. I should really be able to figure out what works on the GS with my little 200XS at that point... will take notes.

 

[allimax]

It definitely could be spinning then grabbing... for some reason I've let off the trottle as it starts to slip as I've never had that be a good thing on other props in the past. Next time I get out, I'm just going to let it eat and see what happens.

I was going through the same thing a few years back it just didn't seem right it would rev so as she broke over. I tried to feather the gas till she caught and things just weren't making sense. I never heard any other bass boat do this so I call Todd and sent him a video. His words to me were "Stand on it son." I've never looked back...

 

[Jon]

Thanks for the advice. Thats how I roll on my dirt bike when its getting loose, so why should it fail me in the boat :very happy

 

[whipper]

Yes like you described. you will get better and better at trimming just right so you don't bog when she grabs. There are props that dont spin as much and just grab the right amount. Those are the keepers.:beer:

Dont do this the first few times but you need to be quite aggressive on the trim as she rolles onto plain. The whole trick is to keep the bow from dropping to far while standing on it the whole time and while she comes over. But the trick is to know were your at so when you reach the next stage of important trimming around the 60-65mph range you can feel when you jump up on the pad. Because from there you really dont want to be over trimmed. its easy to get lost so pay attention and feel the different stages. If your washing the decals above 65/70 back off and try it again and again until your not chine walking. No point in running her up at that point because you wont recover. You have to be not rocking ever bringing her past 70 to be on the safe side and look good.:very happy

the 60-65mph stage of things if your under trimmed a little you will feel it in the bow. it sorta feels like its draging a little. Hold that speed steady and bump the trim once then again and again. You will feel the point when you bumped it just right to free up the bow and let the hull jump up on the pad. {oh you will know for sure} trying it this way. its just a good practice way to feel what thats doing under you. back right off {slowly}} after that if your not comfortable yet and try it again and again. Learning all this in an Allison is half the fun!! i always went to a little calm low traffic lake to practice so I didnt have waves to contend with or other boaters wonder what the heck i was doing..haha i always practised solo so I didn't endanger anyone also. You have wheel to hang on to the passenger doesn't. For you its all fun and games for them its freeky im sure..haha

Watch some Allison drag racing on youtube. you will see when someone does it just right and others are probably swearing in there Helmut because they let the bow drop and created drag.. haha

 

[TBuck2003]

Removing all plugs will make scenario worse. The Allison cut Trophy has a scooped out area at bottom of the blade which makes it different for the air bubbles from exhaust to roll up leading edge of prop. If you allow more air to ventilate it will cavitate more... It might be an inherent scenario when bow breaks over. As long as the boat is still going forward and not stopping, it is acceptable...