I have just started getting interested in rc boating. This migh seem like a very stupid question but how do you hook up the motor to the prop and seal the hull (so It won't leak)? Also how do you hook up the shaft ( im assuming its some kind of shaft to the motor?

I have a hull/boat, motor, esc, prop, battery, transmiter/radio, and a servo. All I need now Is the missing link between the motor and prop.

Any help is appreciated.

Electrolight

There is a coupler that goes between the motor and propshaft. It can be something as simple as a piece of brass with set screws to hold the two parts together or a universal joint for a straight shaft. If you use a flexible cable then you use a collet made for them.
Depending on the hull, there are several ways to seal them. What we call radio box tape is one way to secure the hatch and the hull.

Thank you. It all makes sense now.

Flexshaft rotates in a teflon tube which is housed in a stuffing tube made out of metal. This seals the rotating assembly from the water. Collet, or flex hex is attached from motor to flex cable.

Ryan

Greese on the cable don't hurt either.

i agree with that. i have a boat with the liner and one thats just the brass tube. the one thats just a tube when greased seals out water to the point where the boat is bone dry after a run. the teflon tubbe lets in lots of water.


flex cables are the way to go!!! they are much more forgiving than striaght shafts

Could I just hook up the motor to a flex shaft (using a coupler) go through the brass tube (which is attached to the hull), which I load with grease, and attach the prop to the flex shaft?

Let's go back to square one if you don't mind. It would be nice to know what boat that you have to work with; if it's a kit or ready-to-run boat and what exactly that you have so far.
It sounds like you have it right in your last reply.

I have a custom hull in a v shape thats about 18 inches. The motor and esc on this link http://www2.towerhobbies.com/cgi-bin...?&I=LXLVH2&P=0. And a 10-Cell 12V 1100mAh NiMH batterie. I also have a servo, a 2 channel radio, and a transmiter.

Missing parts a prop some layout for a rudder, a flex shaft, a coupler, a prop, and a brass tube.

Do you think the motor will be strong enough to have fun I mean I'm not expecting 20mph but I hope I'm not building a tugboat?
Also what pitch and size prop should I buy?
And last question is what angle should the prop be pointing pretending like the botom of the hull Is a flat plane and the prop is stiking out making a line with a measureable angle?

Thanks for all your help Ron!

I have no idea what that is but a brushless ESC and motor for 38 bucks is cheap. I'd guess that ESC is about 1/3 what the SV27 is, so you probably won't be breaking any records but it should have some torque. Do you know how many cells it will handle? Keep the boat as light as possible.

Post some photos. If you are running surface drive, 0 degrees would be a good starting point for prop angle.

I'm not sure what prop to use for that motor. Reason is, the air guys that run those motors say they get pretty hot with a light load and are not as efficient as a motor in the same class. For a boat there is no way to water cool it effectively.

As a starting point start on the small side, maybe around 27-30mm.

I don't trust that motor all that much, I was going to toss it in a 3D plane but decided against it and went with a Rimfire. From the specs, that motor should push your boat around 12mph, but it must handle the load first.

Ryan

It can handle 10 cell NiMh/NiCd or 3 cell LiPo batteries.

About how fast do you think It will go?

It will weigh about 1 pound.

I can water cool my boat... I think effectively but Im a begginer. It only works though If my boat reaches 8 mph.[] I hope your right 12 mph would be nice. I'll post some pictures soon. From my understanding a 0 degree prop angle can only be achieved with a flex shaft right?

Thanks for the prop info.

Your motor is an outrunner. It can not be water cooled effectively.

12mph is possible but that motor must be able to run efficient under a load which I don't think it will from what I've heard. Use a flex shaft, that will easily give you a wide range of angular options.

I'd also keep it light by using a 3 cell lipo. That will reduce some of the load on the motor.

Ryan