New prop needed

[bassfisher444]

The plugs fixed the hole shot, but I can still only get 40 MPH running 5800 rpm on the smartcraft gauge. I haven't raised the motor yet,how big of a difference can that make?

[bassfisher444]

According to the calculator my prop slip is 23%, is that about normal?

[Dharr]

If you raise your motor you will gain rpm but possibly gain efficiency with less motor in the water...but gaining rpm means you'll have to go up one pitch or add cup to your prop since your at your max rpm

[bassfisher444]

I am already looking at having cup added or maybe going with a 4 blade since they are supposed to have less slip.

[Dharr]

I was at about the same slip with a black max prop cavitating at wot ..when I went to stainless I kept the same rpms and gained about 5mph now im around 11%...my prop has more cup than the laser...the nrs3 or spitfire will have less slip due to more cup..if your motor is too low like mine was causing drag you will lose some mph too...5.75 sounds really deep for the second hole but you hull is probably different i would raise it one hole and see how it does

[bassfisher444]

Its been a couple months and I am still not much better off than where I started. I raised the motor one hole to the 3rd hole from the top and the top speed dropped about 1 mph down to 39 with the 22" pitch laser 2 but handling improved, I also had to take one of the vent plugs out or it would hardly get up on plane with 2 people and a full live well. Ran it like that for awhile then decided to send it in to Mark to have cup added, In the meantime I ordered a cheap Solas aluminum 21" pitch 4 blade to use while I sent my prop off and I wanted to see how a 4 blade performs. With the 4 blade aluminum my hole shot did improve, and it had more stern lift but I lost some speed and was down to about 37-38 mph, handling wasn't as good as with the Laser either. Got the laser 2 back from Mark, tried it out and I was getting 41-42 mph top speed trimmed up to maximum RPM, however in turns the prop was blowing out and setting the alarm off, I dropped the motor back down to the 2nd hole and that fixed the blowing out problem but I am maxing out a 41mph now. My prop slip is still 20-22% is it possible to get prop slip down to 10-15%?

[jarhead175]

Send it back to Mark and tell him what it is doing. My guess is he will pitch it up 1 more degree.

[Highcentered]

My prop slip is way less than 10% and actually less than 5% when I calculated it. This is with an nrs3 that was bought brand new a couple years ago. Have you parked your boat on a steep hill to make sure all the water is out of the front of the boat? Water likes to sit in the keel area on the Revolution hull and I've seen people have similar issues as you because the hull had water in it they didn't know about. One guy had a 175txw with the 60 on it that wouldn't come out of the hole and when it did was a snail. He NEVER pulled his plug because he was depending too much on his bilge pump but when he let the boat drain on a hill it turned into a rocket again at least for something with a 60hp. One other thing that could be an issue is you might have waterlogged foam in the boat. You bought it used so never know what might have happened. With that 90hp 41-42 sounds pretty acceptable to me depending on how you have it loaded and how many people are in the boat so might just have to find the best combination and not worry about squeezing out that last mph out of it. It's concerning that you have a habit of setting the alarm off.

[bassfisher444]

I pull the plug every time I get it out of the water, I go up plenty of hills so if there is any water in there it should drain out but I rarely ever have and water come out when I pull the plug.

[Highcentered]

Is your motor still as healthy as it was when new? Motors will lose power over time as compression fails.

[bassfisher444]

Is your motor still as healthy as it was when new? Motors will lose power over time as compression fails.

Had 132 hours on it when I got it, I did all the routine maintenance, plugs, fuel filter, water pump, ect. It has about 155 hours on it right now, no issues starting or running and it will turn my 22" pitch prop to the max RPM rating so I would say its healthy. My biggest problem seems to be prop slip.

[bassfisher444]

Also I read a lot about people having issues with porpoising if they trim too much. I have never had an issue with that at all, I can trim up all the way to where it's throwing a rooster tail and I don't have any porposing.

[Highcentered]

Your motor might be too high. I say this from experience from all the hulls I've worked with over the years including several fiberglass bass boats. The problems you're having makes me assume your motor is in the wrong set of holes. Not trying to sound like an ass but you might want to get someone with experience setting up a boat to go out with you and see exactly what the problem is. Sounds to me like you're grasping at straws right now but still haven't blindly found the right one yet. Also keep in mind that your Tracker isn't going to perform like a hull with lifting strakes on it. If you haven't already put that motor as low as possible and see what happens. Yes you will suddenly start to have some porpoising with excessive trim but I bet your prop slip goes way down.

[bassfisher444]

So I should drop it to the first hole even after I lost speed by dropping it from the 3rd hole to the 2nd hole? I'll try it and see what happens.

[Highcentered]

It's a balance to make your prop hook up like it needs to for maximum efficiency. Other possibilities is you could have something keeping your prop from staying in clean water. Is there a blowout ring missing from your prop bore (exhaust going over the prop barrel), cavitation plate damaged, transducer mounted inline with the prop causing water turbulence? Or maybe the hull has a hook in it that's causing excessive drag.

[bassfisher444]

It's a balance to make your prop hook up like it needs to for maximum efficiency. Other possibilities is you could have something keeping your prop from staying in clean water. Is there a blowout ring missing from your prop bore (exhaust going over the prop barrel), cavitation plate damaged, transducer mounted inline with the prop causing water turbulence? Or maybe the hull has a hook in it that's causing excessive drag.

I am not sure if i need a blowout ring or not I'll post a picture, transducer is mounted over and out of the way but I need to move it so I can get a sonar reading while on plane. I checked the hull underneath with a straight edge and it looked fine to me, cavitation plate has a slight bend in it on the front left side, I don't think it's a problem but I could be wrong.
IMG_20200810_175831.jpg IMG_20200810_175853.jpg IMG_20200810_180832.jpg

[Highcentered]

Doesn't look like you need a blowout ring. Not even sure the little Optimax motors came with one but the new 4-strokes do and you really need it in there. That bent spot on your gear case could very well be causing your prop to not be in as clean of water as it should be. One other thing...did Mark totally rework the prop when he had it or did he just add cup to it? If Mark totally reworked it that prop should be good because it's a known good match for your hull after getting worked. Could be you've just had a poorly worked prop all this time and when you had a new one it was the wrong one for your hull. A prop can look 100% fine but be out of spec enough to cause the problems you're having. Prop slip should be way less than 10% and preferably under 5%. You can gain speed by over trimming but that will also increase prop slip and that's not a good thing especially if you lose water pressure. The 175txw hull is VERY trim sensitive where a little goes a long way and one quick bump of the trim is the difference between best overall performance and blowing out.

[bassfisher444]

Mark repaired and added cup to the prop, not sure what all else he did, but he did say he had to do some welding on it.

[Highcentered]

Not saying your prop is an issue but I know for a fact the Powertech nrs3 is an incredibly good prop for your hull. At this point though I just don't know. You might have one of those hulls that wasn't quite right when it came off the line. Have you checked to make sure you don't have waterlogged foam? Boats do get heavy as they age and unless you were around the boat since new you don't know how many times the previous owner let the foam get wet. A good owner is ocd about keeping their boat as dry as possible but too many aren't and those are the ones that never pull the plug.

[bassfisher444]

I have pulled the inserts out of the two rear side compartments and had the plate that the backs of the seats mount to out before and the foam was dry. Any time I am out in the rain I will open all the compartments and let it dry out in the sun all day or put it in the garage with a fan on it for a few days.