Hydrofoil

[mpdive]

OK. I need the experts on this one. When I bought the 2003 Stingray180, it had a Sport Hydrofoil on it. On the maiden voyage, it seemed to porpoise at around 25 mph with the trim all the way in. Got back home and took it off and have not installed it in the last 2 years. Now I'm revisiting the thought of reinstalling it. The boat still want's to porpoise and maybe it's not as bad as what I think it is, but I always ride trimmed in. Boat comes up on plane pretty quickly and is relatively smooth, but in small waves or chop I usually maintain about 24 mph and she does ok. I usually have the young kids in the bow so I'm very careful not to bounce them around. I always watch other boats scooting along and they seem to be bouncing along so I wonder if I am being oversensitive to it. I have tried to trim up while on plane but the smallest increments seem to start it bouncing a little so I trim it right back down. It is may just be characteristic of the ZHULL design on the boat. I was wondering what the hydrofoil might do for me if I reinstall it. If I am already on plane and trimmed all the way in, would it enable a higher speed without porpoising? What advantage might I have if I reinstall it? Thanks for the responses!

 

[90stingray]

Re: Hydrofoil

The tendancy to porpise is the hull design... but usually being full trim down will eliminate this. The hydrofoil should help keep the bow down as well. Stingray hulls usually like 35 mph before any trim... then should run smooth, on up to top mph. Now your boat shouldn't porpise with full trim down at that mph... and especially with a whale tail. Something doesn't seem right to me. Maybe its just bouncing around because its a smaller, lighter boat. She's just not going to cut thru the chop without a little bouncing. If it doesn't porpise on smooth water at that mph, then i would say that's just the chop and that's how she's gonna act. Hope some of this helps... from one Stingray owner, to another

 

[QC]

Re: Hydrofoil

Trim Tabs. Don't look back, Hydrofoils and I/Os are a misapplication.

 

[Mi duckdown]

Re: Hydrofoil

Power trim tabs. .02
Kids up front adds weight forword. Need alot of power to keep bow out of the water.
Balance weight.

 

[mpdive]

Re: Hydrofoil

The tendancy to porpise is the hull design... but usually being full trim down will eliminate this. The hydrofoil should help keep the bow down as well. Stingray hulls usually like 35 mph before any trim... then should run smooth, on up to top mph. Now your boat shouldn't porpise with full trim down at that mph... and especially with a whale tail. Something doesn't seem right to me. Maybe its just bouncing around because its a smaller, lighter boat. She's just not going to cut thru the chop without a little bouncing. If it doesn't porpise on smooth water at that mph, then i would say that's just the chop and that's how she's gonna act. Hope some of this helps... from one Stingray owner, to another

There are sections of the lake we boat in that are smooth as glass and I can open her up without any noticeable bounce. Normal chop forces me to cut back on the speed. I believe it is characteristic of the hull. Someday I would like to find someone much more seasoned than me to take it out with me and show me what's normal. Maybe the Hillstrand brothers would be available! Could be just a smaller lighter boat syndrome. I am one of those take it easy boaters especially with the family aboard. I find myself usually sticking at the speed once it planes off.(18-24) The two small kids together weigh about 150 pounds. The wife sits in the stern to balance it off.
Thanks to all for replying.

 

[mpdive]

Re: Hydrofoil

There are sections of the lake we boat in that are smooth as glass and I can open her up without any noticeable bounce. Normal chop forces me to cut back on the speed. I believe it is characteristic of the hull. Someday I would like to find someone much more seasoned than me to take it out with me and show me what's normal. Maybe the Hillstrand brothers would be available! Could be just a smaller lighter boat syndrome. I am one of those take it easy boaters especially with the family aboard. I find myself usually sticking at the speed once it planes off.(18-24) The two small kids together weigh about 150 pounds. The wife sits in the stern to balance it off.
Thanks to all for replying.

You know the more I look at the way i explained my original post I may have explained it wrong. The boat doesn't porpoise when I'm trimmed down and doing 25 mph or so. What I should have asked is that, why when it try to trim it out a bit does it start to porpoise? I try in small increments and as soon as I do the speed increases which I know is a good thing but then the bouncing starts. This is after just barely trimming it up. I guess the question about the hydrofoil was more about me wondering if it would allow me to plane it off a bit without the bouncing. Or does trimming the engine default or counteract the whole purpose of the hydrofoil. Hope I explained it better and I appologize for the confusion. Somewhere I read that the foil would force the stern to ride higher on plane. I wasn't sure if that was a good thing.
Thanks again!

 

[Mi duckdown]

Re: Hydrofoil

It is a balance of, Trim and speed, and ballast.

 

['78 Crusader]

Re: Hydrofoil

Throw that POS hydrofoil in the recycle bin so you're no longer tempted to use it.

Investigate using the "Smart Tabs"....I promise you that you'll be satisfied.

Those Hydrofoils / Dolefins are for those who are to lazy to find out what's really wrong with their boats.....a bandaide masking the problem. Most times a simple prop change, raising the outboard motor up a few notches on the transom or the addition of trim / smart tabs will solve the problem.

 

[Mi duckdown]

Re: Hydrofoil

Got to start at the beginning.
What speed and RPMS are you running at WOT. with you alone in the boat?

This is i/o correct? Although speed and Rpm relates to every boat and motor.

 

[mpdive]

Re: Hydrofoil

Got to start at the beginning.
What speed and RPMS are you running at WOT. with you alone in the boat?

This is i/o correct? Although speed and Rpm relates to every boat and motor.

I couldn't accurately answer that because I never quite watched the tach that close. I think at 24 mph I was around three grand. It's a 3.0 I may take it out this weekend and get those stats.

 

[dan t.]

Re: Hydrofoil

Some times hydrofoils work as intended, some times they dont, you wont know until you try identical runs with and without it. If you dont have trim tabs I would highly recomend that you get some real ones not those screen door closers ( not so smart tabs) . Bennett are the best,and their customer support cant be beat.

 

[JimS123]

Re: Hydrofoil

Stingray's hull design is very conducive to porpoising when trimming up. Its a price you pay for good performance with a small engine. The company knows that. That's why they now offer a fixed position tab as a factory option.

I knew that years ago. Put trim tabs on my 19' Stingray, but was never 100% satisfied. Then tried a DoelFin. Wow what a difference. Experimented one or the other. What I eventually settled on was having BOTH. Tabs AND a Fin - now that's one sweet ride!

I realize nobody here will agree with me. I would ask "who else has tried it? Doesn't matter to me - I'm 100% satisfied.

 

[mpdive]

Re: Hydrofoil

Stingray's hull design is very conducive to porpoising when trimming up. Its a price you pay for good performance with a small engine. The company knows that. That's why they now offer a fixed position tab as a factory option.

I knew that years ago. Put trim tabs on my 19' Stingray, but was never 100% satisfied. Then tried a DoelFin. Wow what a difference. Experimented one or the other. What I eventually settled on was having BOTH. Tabs AND a Fin - now that's one sweet ride!

I realize nobody here will agree with me. I would ask "who else has tried it? Doesn't matter to me - I'm 100% satisfied.

Thank you Jim. That's good to hear in a way. I know there is nothing wrong with the boat. It has been well cared for. If that ride is inherant to the Stingray then maybe I will try to put the foil back on. Trim tabs would be great as others suggested but I'm not sure how long I will have this one. Something a little bigger with a cuddy would be my choice. I keep telling my wife that now is a good time to sell it since the stripe was just painted and I just hit 109 hours. Not bad for a 2003. Engine is so clean I would eat breakfast off it. I figure it would be an easy sell but she want's to wait.

Oh Yea ......1952 Lyman? Any pics?

 

[JimS123]

Re: Hydrofoil

I just hit 109 hours. Not bad for a 2003. Engine is so clean I would eat breakfast off it. I figure it would be an easy sell but she want's to wait.

Oh Yea ......1952 Lyman? Any pics?

As a matter of fact, "Great Grandma" was just out yesterday. Burned 6 gallons of gas on a 12 mile canal cruise at 5 mph....LOL. The old 24:1 oil burners love their gas....LOL.

The Stingray just passed 1300 hours and 27 years with a tab and a fin.

 

[mpdive]

Re: Hydrofoil

Very Very nice Jim. I'm impressed! They don't make them like that anymore. Craftsmanship at it's finest.