New to me boat porpoising!!!

[auwareagle01]

Hi guys, need some of the expert advice...I've searched the forums but just didn't find quite what i was looking for on my issue. I Just purchased a 2000 Stingray 180rx with a 3.0 mercruiser. The issue I'm having is when running it and i begin to trim it out it starts to porpoise really bad...now I'm talking with very little trim. So the question is why?? Do I need to add a Hydrofoil to control this?? Any advice is much appreciated!!

Thanks, Chris

 

[smokeonthewater]

Re: New to me boat porpoising!!!

IMHO hydrofoil will not help.... just an FYI a friend of mine bought a similar boat and while it did perform fairly well, it had a similar issue. It would porpoise with very little trim input... In addition tho it would blow out also... It came with a badly chewed up (tips of all 4 blades partially missing) 4 blade 20" pitch prop... We put a new 3 blade 19" pitch on it and it now works really well....

I'm not sure what the biggest part of the difference is... the boat being over propped with too much pitch...dropping to a 3 blade... the tips being chewed up


I also would suggest that if it runs well trimmed down then run it that way.... if it feels like the bow is plowing then you have a problem.. You may find that with a bow full of passengers the trim is then needed and much more useful.

 

[jigngrub]

Re: New to me boat porpoising!!!

Did you purchase this boat from a Crimson Tide fan?... it may be trying to buck you off if you did.

Seriously though, trim tabs should help this problem. There's about a gazillion threads on these here, just look back a couple of pages to find the latest one.

 

[auwareagle01]

Re: New to me boat porpoising!!!

It currently has a Quicksilver 3 blade prop 19p

 

[jigngrub]

Re: New to me boat porpoising!!!

It currently has a Quicksilver 3 blade prop 19p

Is it in good shape? Can you post pics of it?

 

[auwareagle01]

Re: New to me boat porpoising!!!

Prop in good shape i would say few little nicks here and there but nothing major.

 

[auwareagle01]

Re: New to me boat porpoising!!!

One other detail.....appears that the previous owner was backing the boat and backed into something...it broke off one side of the cavitation plate.

 

[gtochris]

Re: New to me boat porpoising!!!

How about if you keep the trim all the way down?
I have a similar Stingray but a tad longer, depending where the passengers sit: if I have people in the rear and no one in the front it will porpois, but I even out the weight (re-assign seats), keep the trim down and life is good.

 

[QC]

Re: New to me boat porpoising!!!

Shift as much weight forward and retest. Ultimately trim tabs are the best all around solution and Stingrays are known for porpoising. Many boat builders set their boats up this way as a light bow is typically fastest. The problem is porpoise and then what do you do about it. I had a boat with a similar issue and there was no way to completely control it without trim tabs. That has lead me to believe they belong on all v-hulls whether or not you need them for porpoise control. Amazing tool for v-hulls and they should be standard IMHO . . .

 

[auwareagle01]

Re: New to me boat porpoising!!!

Trim down is not a problem..it's only when you trim up a little...and i mean a little. Everything i know about boats your are to get on plane and then trim out some to get the nose out of the water as to get better ride and fuel economy as you have less boat in water creating less resistance, but with this boat if you trim out any it starts to porpoise??

 

[dhof55]

Re: New to me boat porpoising!!!

View attachment 106833

Smart Tabs will make a world of difference. This is a 2004 190LS. I'm now able to use my trim and have eliminated the porposing.

 

[BamaCharlie]

Re: New to me boat porpoising!!!

I had the same boat you have.
It is a great boat but it will porpoise when you trim up.
I DID add a Foil and it made all the difference in the world. (a lot of people will try and tell you that you MUST but Smart Tabs and not a foil but for the price I like the foil)
I also went to a 4 blade prop and that improved handling.
Where do you boat at?

 

[Trooper583]

Re: New to me boat porpoising!!!

You really should check out smart tabs. Here is a link to a thread I posted just today. I've been running them about two weeks now and I'm very impressed. Also, here is a link to the smart tabs website. They have some pretty informative reading on what a hydrofoil does and what trim tabs do. Finally, most of your foils are at least 50-60 bucks. Smart tabs are 129.00. Worth every penny in my opinion.

http://www.nauticusinc.com/

http://forums.iboats.com/showthread.php?t=505503&p=3403391#post3403391

 

[gtochris]

Re: New to me boat porpoising!!!

Leave it all the way down. It's the simple no cost solution. Every boat handles trim differently and the only occasion I will trim up is if I have passengers in the front or if I am alone and just want to run WOT for a minute and maximize speed.

 

[emilsr]

Re: New to me boat porpoising!!!

Trim for the boat and the conditions. If that means trimmed fully in then so be it. As far as I know there is no rule that says you have to trim out while running.....it just works that way with most boats. You could change to a prop that doesn't provide as much bow lift, but that really isn't going to do much more than what you can do (or not do) with the trim button.

Our current boat likes the drive to be buried until you're running 45+mph, then you can start to trim up slightly. Highest speeds with a bow lifting prop are achieved with the drive level to the bottom of the boat. It's just the way that boat responds. Yours doesn't like trim either.....no biggie, just trim accordingly.

On your prop, if it has "a few little nicks" it needs to be repaired.

 

[auwareagle01]

Re: New to me boat porpoising!!!

Thanks for the responses, i will look into some of the options and decide what to do. So as far as the prop.....some have said to get it repaired if it has any "nicks"...any ballpark on what that would cost

 

[dockwrecker]

Re: New to me boat porpoising!!!

I paid $80 for a rebalance/pitch check on a stainless prop last year.