Sport 40 transom mounted strut

[Greg Bonahoom]

What is the final verdict on the new rule change after almost a full season of racing? Do I need to mount my strut on the transom to compete at the big races? Did the sport 40 winner at Hobart have his strut on the transom or mounted underneath? I am new to the class and my strut is mounted underneath. The boat corners like it is on rails. (Phil Thomas hull) I don't want to mess with it if I don't have to.

 

[P THOMAS]

Dont change or worry about your setup.

Seems to me on my SSP45 the rear strut put too much load on the prop at launch and at speed it made the boat just act funny, spin or get real flightyat times. Steve Petersen boat setup with rear strut mad his boat stuff when it crossed a wake, didnt last two heats that way and he had it under the boat.

Now the ML boat may like it or some other designs that consider the extra length the rear strut gives the afterplane it should work ok

 

[Greg Bonahoom]

Thanks Phil! I will leave it alone.

 

[P THOMAS]

I would like to hear of other good setups for the rear strut option, any one post about this.

 

[Samuel Hagan JR]

How much of a different setup do you think it would require to work on your hull Phil. Moving the motor back or forward.

 

[tom galdys]

The guys up in Canada should have a good answer for you. They seem to like it but I agree that my PT runs on rails with in under the boat. Phil's boats run great with it under. Thanks Phil

 

[P THOMAS]

How much of a different setup do you think it would require to work on your hull Phil. Moving the motor back or forward.

Well I dont think the motor position would change much. Im sure my boat would work with the rear strut, many have been setup for FE with the strut on the back, one even went over 100mph, but that just in a straight line. i really didnt give it much testing was having motor problems too.

 

[P THOMAS]

Thanks Phil! I will leave it alone.

Just be sure to seal up the slot on the strut blade with a bit of silicone so water wont pump into the hull.

 

[Mike Betke]

So far the testing on my new hull has proven no advantage. I have had to downsize the prop from what I ran on my previous boat. I will be putting the strut back under the boat. I believe that the cushion of air under the transom helps hold the prop up better.

 

[Robert Pickard]

The only advantage i see with it on the transom is your making the boat longer, never could understand the change in the rule, why change something that doesnt need to be

 

[FloridaScaleBoater]

The only advantage i see with it on the transom is your making the boat longer, never could understand the change in the rule, why change something that doesnt need to be

It was POLITICAL,,,,

 

[Samuel Hagan JR]

So far the testing on my new hull has proven no advantage. I have had to downsize the prop from what I ran on my previous boat. I will be putting the strut back under the boat. I believe that the cushion of air under the transom helps hold the prop up better.

When you mean cushion of air under the transom are you talking about the airtraps under the boat or the very back. Is that why some guys have those long 1/8th inch runners on the rear bottom.

 

[James Schmidt]

Are a lot of the sport 20s run with prop under boat?

Jim

 

[Mike Betke]

So far the testing on my new hull has proven no advantage. I have had to downsize the prop from what I ran on my previous boat. I will be putting the strut back under the boat. I believe that the cushion of air under the transom helps hold the prop up better.

When you mean cushion of air under the transom are you talking about the airtraps under the boat or the very back. Is that why some guys have those long 1/8th inch runners on the rear bottom.

The cushion of air as I describe it is the air passing under the hull. As the air passes under the boat, the boat is held up. The way that the bottom is shaped will reflect how the hull handles. Most Sport boats have a flat bottom for the rear half of the hull and that is probably the best scenario for holding the rear of the boat up at speed. The air traps down the side will help hold the air under the hull.

Take a look at the modern hydroplanes of today that run the props farther behind the transom. They have also recessed the transom and run the sponson canoes and rear shoes as far back as the prop for support.

 

[Hydro Junkie]

Actually, most run the shoes well past the prop and have air traps that are anywhere from 4-6" below the bottom of the boat to retain air. The Oberto runs 4" deep traps and has a left shoe that extends 26" past the transom, the right is slightly shorter. The prop hub, conversely, is only an inch or so past the transom

 

[Robert Pickard]

I know Rick that is the problem this is for fun to many politics ruining the hobby

 

[P THOMAS]

So far the testing on my new hull has proven no advantage. I have had to downsize the prop from what I ran on my previous boat. I will be putting the strut back under the boat. I believe that the cushion of air under the transom helps hold the prop up better.

When you mean cushion of air under the transom are you talking about the airtraps under the boat or the very back. Is that why some guys have those long 1/8th inch runners on the rear bottom.

Even with out air traps there is a cushion of air under the hull for lift, controlling that lift is the problem. My SSP45 air traps were adjusted to give the right amount of lift to the rear we had to adjust the length to adjust the ride.

 

[Don Ferrette]

I know Rick that is the problem this is for fun to many politics ruining the hobby

ENOUGH ALREADY!! There was NOTHING "political" about this, now ALL of the IMPBA sport hydro classes have the SAME RULE as for mounting the strut. It's time for some of you to get over it and move on.

 

[Robert Pickard]

All my question is why not keep both NAMBA and IMPBA rules the same on the sport boats makes it hard when a NAMBA memeber goes to a big IMPBA JMHO

 

[P THOMAS]

All my question is why not keep both NAMBA and IMPBA rules the same on the sport boats makes it hard when a NAMBA memeber goes to a big IMPBA JMHO

COME ON MAN Just add something about boats useing a rear strut not rule debate.

OH go read your NAMBA rule book and find this in sport hydro rules.. 7. Outdrive assemblies will be allowed.