42" sprint cat conversion

[Rumdog]

Aaaahhhhghggg!! Again.. Move the cg forward a bit and you'll be fine.

[rearwheelin]

Aaaahhhhghggg!! Again.. Move the cg forward a bit and you'll be fine.

Why couldn't you just say that without the "Aaaahhhghgg!" ? Everyone is untitled to there opinion.... However I do understand when someone needs to be right all the time !

[Rumdog]

Every time someone has a handling issue, you attribute it to that same exact, false thing. You're basically saying that if I completely arc my stuffing tube, 180 degrees from the prop that my boat would sit stationary, since the force is applied to the motor shaft. Id say, In general 90 percent of us run a gap between the DD and strut/stinger, as you SHOULD, and it doesn't effect the handling what so ever.

[rearwheelin]

Every time someone has a handling issue, you attribute it to that same exact, false thing. You're basically saying that if I completely arc my stuffing tube, 180 degrees from the prop that my boat would sit stationary, since the force is applied to the motor shaft. Id say, In general 90 percent of us run a gap between the DD and strut/stinger, as you SHOULD, and it doesn't effect the handling what so ever.

I see what you are saying but I have posted how many times in the last three years on this subject ?? LMAO

[rearwheelin]

Besides what you think , did you know that if you put a negative tilt on your motor you can actually make a boat nose dive under acceleration ? What ever your battle is here I'm just trying to help the OP and note high jack this thread....

[Fella1340]

What are you talking about? Are you saying you adjust your motor in relation to the stuffing tube and you do this to change handling? Sorry, I didn't understand what you were saying above, at all.

[rearwheelin]

What are you talking about? Are you saying you adjust your motor in relation to the stuffing tube and you do this to change handling? Sorry, I didn't understand what you were saying above, at all.

Exactly ! It is a hard concept to grasp for some . Not saying either way is better . I do believe there are perks to both types of set ups . For example the gyroscopic effect of the motor will be the same in both drive set ups but when you run a gap between your drive dog and strut this actually transfers your boats thrusting point to your engine . When you shorten the gap enough this will put the boats thrusting point at the transom because your drive dog will be pushing on the strut instead of your stuffing tube and motor.

[Fella1340]

Ok, I get transferring the load from the motor to the strut or stinger. I have thought about it before but factoring in the flex cable shortening under load and really needing a thrust bearing at the strut or stinger to make it effective I don't think it's a great choice. Figuring out the flex cable length under load and getting a proper preload on the thrust bearing seems a frustrating endeavour to take on. Given the load would be transferred back and forth between strut and motor under acceleration and deceleration and likely at lower speeds I don't think it's worth the bother. You also run the chance (very likely)of setting it up incorrectly and overloading the strut thrust bearing and causing large amp draw on the motor. I think getting the setup to run efficiently isn't worth the bother. If your running a wire drive then I would investigate it further, it makes sense If your driveline isn't constantly changing length. For flex shaft users (vast majority) it just isn't worth it.

[rearwheelin]

Ok, I get transferring the load from the motor to the strut or stinger. I have thought about it before but factoring in the flex cable shortening under load and really needing a thrust bearing at the strut or stinger to make it effective I don't think it's a great choice. Figuring out the flex cable length under load and getting a proper preload on the thrust bearing seems a frustrating endeavour to take on. Given the load would be transferred back and forth between strut and motor under acceleration and deceleration and likely at lower speeds I don't think it's worth the bother. You also run the chance (very likely)of setting it up incorrectly and overloading the strut thrust bearing and causing large amp draw on the motor. I think getting the setup to run efficiently isn't worth the bother. If your running a wire drive then I would investigate it further, it makes sense If your driveline isn't constantly changing length. For flex shaft users (vast majority) it just isn't worth it.

This why 90% don't do it..... It's really not this complicated though. The flex doesn't shrink as much as one would think.

[Rumdog]

Sure it does. Easiest way to see that is to leave too little gap and you'll see wear on the dd strut or bushing immediately. The ride attitude comes from prop angle, not motor.

[Fella1340]

The flex would still be loading and unloading transferring loads from strut to motor. If you managed to eliminate it your likely running with a loaded flexshaft on the strut. The only place this has merit is a solid drive, like a wire drive. In my opinion anyway, not worth the bother

[rearwheelin]

Post 71 @ 57 second mark.... You can see the aero dynamics of the boat kick in when the boat levels speed, it happens so fast that it's really obvious to me something isn't right. Either his prop is digging in bad or the motor is nosing the boat up. He at least needs to raise his strut out of the water some. The way I test the flex for clearance at the strut is by putting a wrench on the collet and twisting the prop hard using leather gloves, not that much shrinkage. I would say under acceleration bumping the dog against the bushing would help keep the nose down.

[Rumdog]

And exactly how often is the flex fully loaded like it is while you're applying that twisting pressure by hand? Once again, however, the thrust comes from the prop, and the direction it is aimed, not the motor angle. If I run my motor vertically, will my boat fly?!?!

[rearwheelin]

And exactly how often is the flex fully loaded like it is while you're applying that twisting pressure by hand? Once again, however, the thrust comes from the prop, and the direction it is aimed, not the motor angle. If I run my motor vertically, will my boat fly?!?!

No it won't fly ! The force on your stuffing tube is what pushes the boat ! My buddy was allways snapping cables with his outboard hydro , vertical motor ! Tell me why the conquest hull wich has the same lower half as this sprintcat wich is pushing 9.75 hp on 4s is a dart when squeezing the throttle ! By the way he is running thrust washers with about a half a mm gap ! lol

https://m.youtube.com/watch?v=V5SjfVDsRow

[rearwheelin]

And exactly how often is the flex fully loaded like it is while you're applying that twisting pressure by hand? Once again, however, the thrust comes from the prop, and the direction it is aimed, not the motor angle. If I run my motor vertically, will my boat fly?!?!

No it won't fly ! The force on your stuffing tube is what pushes the boat ! My buddy was allways snapping cables with his outboard hydro , vertical motor ! Tell me why the conquest hull wich has the same lower half as this sprintcat wich is pushing 9.75 hp on 4s is a dart when squeezing the throttle ! By the way he is running thrust washers with about a half a mm gap !

https://m.youtube.com/watch?v=V5SjfVDsRow