Blunt the nosecone

[GotMyAlly]

The way it was explained to me, a sharp point is good if it runs straight thru the water. You mainly see speedmasters on light/fast boats. Boats like that don't need a lot of trim. On a bass boat, you end up running a couple degrees positive trim to carry the weight. With the blunt nose, the leading edge splits the water the same whether it is level or a few degrees above level trim. The picture of mine may not accurately represent it at the angles in the pics, but mine is blunt when you look at it from the side but if you look at it from above or below it carries the sharper edge of the leading edge fo the gearcase on down through the tip.

 

[suicidealli]

We have been blunting Bobs cones and CLE's etc for years. Its not rocket science. You are trying to keep the water attached to the gearcase more easily. We don't blunt ours nearly as much as the ones in the photo, more like the size of your index finger. You could do a speedmaster as well, but their aspect ratio is already good at keeping water adhered pretty well. Also closing off one of the water inlets decreases aeration of the water going by on one side and allows for a slightly better bite. Some do port, some starboard. Smoothing the rough edge by the inlet helps as well , as does filling the drain hole on CLE and 200 cases and using rear drain carriers or just removing the putty etc when filling and replacing it afterwards. Skeg work helps , as does torque tab work.

steve is right!!!!! blunting a nose on a sporty is as easy as it gets...
the theory, or fact is that is creaest a air pocket around the side of the case. less friction = more speed. the same theory of a 747 jet!!!!!!!!!!!

sharp point = friction lower speed. doesnt handle as well.
perfect blunt speed goes up. handleing is better, less friction.

to blunt = blow out, not enough water hitting the back of the case. the "air pocket" is to big. some people will add a blow out ring to compensate. may work , may not.

the happy medium is great. my sporty went up 2 mph. handleing was better as well. i like a worked sporty on a ally. number one case of choice on a ss for around boating.JMO

roy

 

[K-DAWG XB 2003]

I am pretty sure Tyner is running around 120 with a stock sporty. Could be wrong but, if you do a search I am pretty sure theres a thread here somewhere talking about it.

 

[chad202]

A stock sporty is more blunted than a standard coned case. My nose is out the water when running wot and light loaded.

 

[jas638]

steve is right!!!!! blunting a nose on a sporty is as easy as it gets...
the theory, or fact is that is creaest a air pocket around the side of the case. less friction = more speed. the same theory of a 747 jet!!!!!!!!!!!

sharp point = friction lower speed. doesnt handle as well.
perfect blunt speed goes up. handleing is better, less friction.

to blunt = blow out, not enough water hitting the back of the case. the "air pocket" is to big. some people will add a blow out ring to compensate. may work , may not.

the happy medium is great. my sporty went up 2 mph. handleing was better as well. i like a worked sporty on a ally. number one case of choice on a ss for around boating.JMO

roy

hey roy, i thought the same theory about the 747 jet. but i didnt post up on it cause then i thought about all the fighter jets and the fact that they have a pointed nose? i dont think it the guys that fly them would say it makes them handle worse. but thennn..... i said to myself comparing nose cones on jets to nosecones on lowers is maybe apples to oranges . one flys through the air the other through the water. maybe the point is moot?

 

[jas638]

A stock sporty is more blunted than a standard coned case. My nose is out the water when running wot and light loaded.

well it gets back to what i said about what titus explained about the design off the case. from the side if you have ever really looked at a sporty the tip of the cone is higher than the shaft. hence the use of the term "elf shoe". titus term.

 

[whipper]

hey roy, i thought the same theory about the 747 jet. but i didnt post up on it cause then i thought about all the fighter jets and the fact that they have a pointed nose? i dont think it the guys that fly them would say it makes them handle worse. but thennn..... i said to myself comparing nose cones on jets to nosecones on lowers is maybe apples to oranges . one flys through the air the other through the water. maybe the point is moot?

Hence super speed masters are the fastest case. The stream lineing must have a lot to do with it? If the sides of the case are wide like a football then blund. If more narrow like a SSM or arrow then point. I sure would like to see a wind tunnel effect on these shapes.

 

[suicidealli]

the fighter jet is very sleek and narrow...... the 747 is huge. the sporty is shaped different the elf shoe....... that is why you can run them higher....

roy

 

[propmanjay]

My SS would tttake a scary right lean at anythig over 104. After890-=

 

[propmanjay]

Sorry, spilled coffee on my key board. Mine took a scary right lean at anything over 104 and was very sencetive to any imput. After blunting it I could run over 110 with out the lean. Not sure why but it worked. I couldn't tell any difference until 104 up. I never run much more than level with the trim or the SSr or it would want to come around. I don't think you will see much difference with a moded SM untill you are 100+. It was very easy to drive until 104 stock or moded.

 

[h2oskiier30]

i agree with you 100% .but i still will wonder why not just use a cle and cone it? unless you wanna run a fat shaft sporty? jus askin?

I bought the motor with the sporty already coned. However, knowing what I know now, if I had a stock sporty, I would not hesitate to send it to Titus to have him cone it.

 

[jas638]

gonna be shuttin down for a week to go on vaca. somewhere in the carribian. would like to say thanks to you guys for the topic and correspondence. it realy is a pleasure to talk with you guys about this stuff. i have learned alot. we trully are a bunch of motor head speed freaksss!!! i love it!!!! thanks,john

 

[propmanjay]

I am going next week on a 7 day cruse maybe I will see you there.

 

[whipper]

Maybe you guys can get the Captain of the cruise ship to get the most out of that 500 fter.:big grin I wonder what Captains of ships drive for there personal boats? After a month at sea in the 30KT range with a direct drive you would think they are going crazy for a SS 300Drag with a blunt nose SM on days off.

 

[AMERICAN]

I bought the motor with the sporty already coned. However, knowing what I know now, if I had a stock sporty, I would not hesitate to send it to Titus to have him cone it.

I never seen a coned sporty,can you post some pics when you get a chance...

 

[K-DAWG XB 2003]

Click this link and scroll down. Has a series of pics of him moding a Sportmaster.

http://www.low-h2o.com/testimonial.htm

 

[TBuck2003]

Speedmasters or Super Speedmasters are pointed for two reasons:

1.) They only go on boats that do not REQUIRE bow lift to obtain top speed or lift. In simple terms Race boats, that have a high Horsepower to weight ratio.

2.) At level trim the point is perfectly ok with water flow. At positive trim ( Pleasure Boat) You are now dragging the point through the water like a plow in a field which = poor water flow back to prop.

Getting back to the 747 discussion that has to do with Aspect Ratio which is the dynamic of length X width. The fatter an object is the longer it must be to to punch a hole through the air or water. The fighter Jet is a Speedmaster on a race boat with a high H.P. to weight ratio. The 747 is Pleasure boat that you want to go fast. This is the same reason a CLE stock is an accident waiting to happen. Has point and is short in length compared to its girth. This is the same reason a XR6 Steckbauer is not only faster but safer (Less Girth) The Stecky can also be a little shorter because it is a 1/2" less in diameter.


TBuck

 

[AMERICAN]

Click this link and scroll down. Has a series of pics of him moding a Sportmaster.

http://www.low-h2o.com/testimonial.htm

Thats a great link,I now do remember seeing that type of case just never though it was a sporty......thanks for the link

 

[whipper]

Speedmasters or Super Speedmasters are pointed for two reasons:

1.) They only go on boats that do not REQUIRE bow lift to obtain top speed or lift. In simple terms Race boats, that have a high Horsepower to weight ratio.

2.) At level trim the point is perfectly ok with water flow. At positive trim ( Pleasure Boat) You are now dragging the point through the water like a plow in a field which = poor water flow back to prop.

Getting back to the 747 discussion that has to do with Aspect Ratio which is the dynamic of length X width. The fatter an object is the longer it must be to to punch a hole through the air or water. The fighter Jet is a Speedmaster on a race boat with a high H.P. to weight ratio. The 747 is Pleasure boat that you want to go fast. This is the same reason a CLE stock is an accident waiting to happen. Has point and is short in length compared to its girth. This is the same reason a XR6 Steckbauer is not only faster but safer (Less Girth) The Stecky can also be a little shorter because it is a 1/2" less in diameter.


TBuck

Great info Todd!! Is there a formula for this some were. I reshaped my gearcase last fall and the result wasnt very good. I lost 3 mph. I blamed my pad setup i repaied but at the same time redid the gearcase. I sharpend the leading edge down to the nosecone. Sharpend the skeg and narrowed the case shape by sanding a lot off the sides stream lining it. Also made a bit more point. OOOOPS. Looks like I will be adding some shape to it and dulling hear and there based on this info.:big grin I need to look at the case shape carying the hull in her position more like a boat behind the boat with a little more trim than nutral to get the shape right. Correct?

 

[TBuck2003]

Whipper call me I can talk better than type !!!!

TBuck