sport 40 that blows of or is very light on the front.

[tmunn]

I have a phil thomas sport 40 that i rebuilt last winter and Today was the first time out to our big pond where i could let the picco 45 wind up and not have to worry about room.

It's running really well and gets better each time out . not real fast but a fun boat none the less.

It is however light on the nose or tail heavy despite the fact the radio box is in the nose.I built the namba filled in tunnel mod that some guys were doing and it could be alift issue also.

Is the preffered method to control the front lifting and a little sponson hop down the straight . to add some weight to the sponson tips,the nose, or the radio box, or over the cg or use negatine strut angle.

I am trying to get my maximum speed and have a boat that works well in most water conditions.

picco 45 stock s/b x450 and parabolic pipe.

I am just working with it now and am running prolly low to mid 50's i would guess.

It started to turn on when i went from 10-1/8 on the pipe to 9.7/8"I will try shorter next time out.

 

[Hydro Junkie]

Oh boy, this one could be fun. I see several options, but not all are good ones. If I remember right, an X450 is a non-lifting prop. If I'm right, you might start out with a lifting prop to get the back end higher and plant more weight on the sponsons. Next option would be to attach some stick on weights to the front of the sponson decks. This way you could see if the weight makes a difference without making it perminent. Other than that, you might contact Phil and see if he has any other ideas

 

[P THOMAS]

drop the strut and add angle if it runs loose, Did you have the baseline setup or just guessing?

 

[Hydro Junkie]

Thanks Phil

 

[tmunn]

Phil, i "think" i have the setup here in an e- mail .would you be able ro send them to me again please in case i cannot find them.

[email protected]

 

[P THOMAS]

Phil, i "think" i have the setup here in an e- mail .would you be able ro send them to me again please in case i cannot find them.

[email protected]

OK The setup has changed since 08 when the new bottom was done. Strut depth was 1 1/8" it should be 7/8" now.

Run the strut flat if you can, I have about 1/16" higher in the front of the strut on my boat. and I have about 3 oz lead strip around the front fuel tank and add another strip if it is really gusty winds.

Your running the front radio box which tends to set the boat better in the water. get the balance ok and it should trim out well. Get the fuel tanks just ahead of balance point too.

Here is the part from the setup sheets on trimming.

10. TRIMMING THE BOAT

The hull should balance about 18-19 inches from the transom without fuel.

The 7/8” inch strut depth is a good starting point. If the boat rides too light on the water, adjust the strut deeper. If the front sponson are running too hard on the water adjust the strut higher until the boat rides flat on the water but will not blow off.

The strut can be set up flat on the table and at a depth of about 7/8” deep from the hull bottom to the table. Small adjustments to the strut angle can be made also. Set the front of the strut about 1/16” higher. Weight can be added to the nose or sponson tips to fine trim the hulls balance point if needed. Insert lead strips in the end of the pipe insulation, tyrap the flotation tube end to hold the weights at the tip of the front sponsons. More weight in the left sponson tip helps trim the boat balance point, add 2-4 oz. Once the boat is set up correctly no changes should be necessary for smooth or rough water other than adding weight to the nose. On a calm day the boat may spray water from the forward steps of the front sponson, raise the strut to lighten the boats ride, but be careful not to make it too loose when racing on rougher water. In rough water the boat may look like it is too loose on the water, do not change the trim unless the boat tends to blow off.

 

[BobGutsell]

Would adding a ride plate to the underside of the stuffing tube help?

 

[SayMikey]

Phil, i "think" i have the setup here in an e- mail .would you be able ro send them to me again please in case i cannot find them.

[email protected]

I yse wiper blades under the front works well And a backcut 1455 helps pick the back up. Where is the drive dog?

 

[tmunn]

The distance from the transom to the flat side (not the part that the prop rests against)to the dd is aprox 1/2" .my strut is inside the boat.

MIke send me a pic of your blade idea .i have heard that before.Also are you going to the Norther nats ?

I lowered the strut last outing and that made a difference I will measure it tomorrow and see where i am compared to phils notes and check my c/g also.

[email protected]

 

[SayMikey]

The distance from the transom to the flat side (not the part that the prop rests against)to the dd is aprox 1/2" .my strut is inside the boat.

MIke send me a pic of your blade idea .i have heard that before.Also are you going to the Norther nats ?

I lowered the strut last outing and that made a difference I will measure it tomorrow and see where i am compared to phils notes and check my c/g also.

[email protected]

Terry if your strut is under the boat make your stuffing tube extend to the transom. We have found if the drive dog is 1/4 inch behind transom it will gain as much as 10 mph.

 

[tmunn]

Mike, if i follow what your saying ,,,i could just cut 1/4" off my cable and that puts my Drive dog aprox 1/4 from the transom.

The strut I used is one that extends but the way it is mounted in the boat it is almost flush with the transom.

I will post a picture tomorrow if i get a chance.

 

[P THOMAS]

Mike, if i follow what your saying ,,,i could just cut 1/4" off my cable and that puts my Drive dog aprox 1/4 from the transom.

The strut I used is one that extends but the way it is mounted in the boat it is almost flush with the transom.

I will post a picture tomorrow if i get a chance.

Terry the strut should be flush with the transom that sets the drive dog correct. IMPBA rule is strut must not be behind transom, this is also for NAMBA.

 

[tnrcboatracer]

Would adding a ride plate to the underside of the stuffing tube help?

This is not legal in IMPBA. No additional lifting surfaces are allowed. But a flat bottom strut is allowed(go figure).

 

[Hydro Junkie]

Would adding a ride plate to the underside of the stuffing tube help?

This is not legal in IMPBA. No additional lifting surfaces are allowed. But a flat bottom strut is allowed(go figure).

To go one step further, any kind of ride plate or surface extension below the hull is not allowed in NAMBA, IMPBA or APBA. The only drive system that can any kind of plate near the prop is the outboard lower end anti-cavitation plate. Even a belly pan for engine clearance CANNOT EXTEND LOWER THAN ANY DESIGNED IN RUNNING SURFACE. Still trying to figure out how the flat bottom strut is legal myself :huh:

 

[M@MRacing]

I have seen many a long time racers down here in District 3 use flat bottom struts.

 

[Russ Nachtweih]

Would adding a ride plate to the underside of the stuffing tube help?

This is not legal in IMPBA. No additional lifting surfaces are allowed. But a flat bottom strut is allowed(go figure).

To go one step further, any kind of ride plate or surface extension below the hull is not allowed in NAMBA, IMPBA or APBA. The only drive system that can any kind of plate near the prop is the outboard lower end anti-cavitation plate. Even a belly pan for engine clearance CANNOT EXTEND LOWER THAN ANY DESIGNED IN RUNNING SURFACE. Still trying to figure out how the flat bottom strut is legal myself :huh:

Junk,

What is an "outboard lower end anti-cavitation plate"?

Thanks,

Russ

 

[LarryConrad]

Terry,

If you are blowing off the water with the new style bottom, you don't have your weight distribution correct.

 

[tmunn]

Thanks guys I have made some changes and will see what happens next time i go out and have time to test.

 

[Hydro Junkie]

Would adding a ride plate to the underside of the stuffing tube help?

This is not legal in IMPBA. No additional lifting surfaces are allowed. But a flat bottom strut is allowed(go figure).

To go one step further, any kind of ride plate or surface extension below the hull is not allowed in NAMBA, IMPBA or APBA. The only drive system that can any kind of plate near the prop is the outboard lower end anti-cavitation plate. Even a belly pan for engine clearance CANNOT EXTEND LOWER THAN ANY DESIGNED IN RUNNING SURFACE. Still trying to figure out how the flat bottom strut is legal myself :huh:

Junk,

What is an "outboard lower end anti-cavitation plate"?

Thanks,

Russ

If my terms are off, I appoligise, that molded in flat plate right above the prop on the K&B outboard. Not sure if the OS has it or not. Can you all tell I don't run outboards

 

[LarryConrad]

Would adding a ride plate to the underside of the stuffing tube help?

This is not legal in IMPBA. No additional lifting surfaces are allowed. But a flat bottom strut is allowed(go figure).

To go one step further, any kind of ride plate or surface extension below the hull is not allowed in NAMBA, IMPBA or APBA. The only drive system that can any kind of plate near the prop is the outboard lower end anti-cavitation plate. Even a belly pan for engine clearance CANNOT EXTEND LOWER THAN ANY DESIGNED IN RUNNING SURFACE. Still trying to figure out how the flat bottom strut is legal myself

Junk,

What is an "outboard lower end anti-cavitation plate"?

Thanks,

Russ

If my terms are off, I appoligise, that molded in flat plate right above the prop on the K&B outboard. Not sure if the OS has it or not. Can you all tell I don't run outboards

What do outboards have to do with Sport 40 Hydros?