Sport 20 Hopping In Corners

[darryl whitman]

hi guys , my ML310 sport 20 is hopping in the corners , do I add weight in front or play with the turn fin.

she runs level in the straights . P spec , x445 prop, turn fin is 1.75 inch under sponson,

 

[anthony_marquart]

My GP hydro had the same issue. I sanded the running surfaces to about 440,.. up the side of the sponsons too.. and the bottom of the boat. in my boat the outside sponson was sticking to the water in the turns, pulling the front down and making the tail hop... Mine liked the 42mm diameter prop, maybe get a prop with less diameter and more pitch.

 

[darryl whitman]

thank u , Anthony, u said your tail would hopp. its my front that's hopping in corners , sanding the surfaces like u said should still help.

Ill go back to my 442 porp , an see what she dose.

 

[SayMikey]

What are you using for a turn fin

 

[anthony_marquart]

Yep it sounds like you need more fin

 

[darryl whitman]

I'm using an aquacraft 20 style fin

 

[Hydro Junkie]

When you say your boat's "hopping", is the fin "unhooking", being totally out of the water with the boat sliding left or is the boat just bouncing in the turns while holding a steady arc?

 

[Don Ferrette]

I'm using an aquacraft 20 style fin

Where is your CG at? Is there any negative in the strut angle? With that being said that AQ fin is NOT a good choice for the ML sport hydro. The best turn fin is one from Dick Tyndall, I have one on our 310 P-limited ML sport hydro and it works pefectly, boat is silk smooth in the corners. Strut is set up neutral (flat) with boat bottom parallel to set up table.

 

[Bert Dygert]

Darryl,

Check that the bottom edge of the skid fin is parallel with the bottom of the boat. If it's rotated so the back of the skid in is lower than the front it maybe riding up of the skin fin in the corner causing the hop. If you can rotate the skid fin so the leading edge of the skid fin is slightly lower (negative) than the back the boat should tighten up in the corner.

Strut angle and prop lift will also come into play. My GP-310 (nitro version) is set up with one degree angle in the strut and the bottom of the boat is flat with the table top meaning that my hull is what they call neutral.

If the skid fin is to small the boat will slide out in the corners.

I not sure where you should be with the electric version because of your battery weight being so far forward. If you use the boat of the parallel to the table when the boat is up on the prop you will be running slightly negative.

Bert Dygert

 

[namba276]

The best fin is a Mike Hughes fin...bar none!

 

[Don Ferrette]

The best fin is a Mike Hughes fin...bar none!

I've run Mike's fins and they are pretty good, have you ever run one from Mr. Tyndall??

 

[namba276]

I haven't...I really like the Hughes fin... It's narrow and makes my boat turn like a tether boat.

 

[Chris Wood]

flatten out the strut.. that will also make the nose of the boat light so go in SMALL SMALL incerments.

also turn fin like has been mentioned AND look at the prop.. alot of times prop's cause back end chatter both in the turns and on the saw's.

 

[Chris Wood]

also height of the strut can cause chatter.. i know on a sport 20 i used to race i was adjusting the strut down to .010 increments. took a while but it was dead on when it was right

 

[SayMikey]

Who is this washed up has been Mopar freak Chris Wood

 

[Marty Slater]

I believe you have it right Mikey

I keep hoping that washed up has been would come out of retirement

an bring that old skinny dude with him to

Marty

 

[darryl whitman]

ok . how do I get ahold of Dick Tyndall. thanks to u guys for your help, Marty Slater an the guys here in Iowa, got me hooked on boating,

now I got to hide more money from the wife , LOL

 

[moparbarn]

He goes by El Zorro here. I use his fins on everything!

 

[Hydro Junkie]

Plan on a bit of a wait as Dick tends to be very busy. If you want to do it up right, a bracket for the fin would be a good choice as well

 

[Mike Larson]

Darryl... sharpen the things i asked you to FIRST.... ( sharps sharp, and BLEND)... I have a spt 20 fin for you to test if yours still quirks... the **** thing is anodized purple, so you may have to repaint.... lol... we're going to start over... per your strut and turn fin depth... fin off on the table use wood blocks to shim the boat rear to level and get a look per your strut depth/angle?, ... fin depth/angle.... Chris' spt 20 was nitro powered and the fastest id ever seen.... welcome to in actuality, why, we're actually testing all those sundays... all i can say is during the weeks after work I'm tweaking failures... ( fins, props, whatever) sunday tells the tale.... we'll work on it.... its going around, and fine tuning/trimming is basically you get back what you put in.... lots of great help posting here.... thanks guys.... Mike