Sealed drive shaft?

[FighterCat57]

I'm building and experimental craft and want to make it as water tight as possible. I'm thinking that a 4mm solid shaft would work, but curious how to seal the transom exit point.


Perhaps a sealed bearing system?

Any suggestions, I'm sure there's something out there already.

[ED66677]

rigid drive shaft are made of :
the shaft itself let's say it is 4mm OD
a brass tube (5mmID) that has bushing at each end, bushing are 4mmID
once the shaft is in the tube, the volume between shaft and tube is filled with any grease via a hole on the ouside of the tube... it is water tight!

[FighterCat57]

rigid drive shaft are made of :
the shaft itself let's say it is 4mm OD
a brass tube (5mmID) that has bushing at each end, bushing are 4mmID
once the shaft is in the tube, the volume between shaft and tube is filled with any grease via a hole on the ouside of the tube... it is water tight!

So basically, I could use a cable drive strut and not worry about water coming back in the hull. The motor will be mounted at or below the water line in this project. My concern is water coming in through the drive tube.

If a lubed cable is all it takes then I should be good to go!

[ED66677]

rigid shaft in a tube is commonly used on scale boat with sub surface prop!

[CornelP]

Try these:
http://www.offshoreelectrics.com/pro...t+Drive+Shafts
:)

[FighterCat57]

Try these:
http://www.offshoreelectrics.com/pro...t+Drive+Shafts
:)

Yep. That looks like the simplest and least expensive route to go!

Although if I can get a jet drive/brushless setup... I'm so there!

[sailr]

I know somebody will say they NEVER get water through their shaft. No matter how hard you try, water seems to find a way in. Put a small piece of sponge under where the shaft enters the boat, next to the motor coupler. This will soak up a small amount.

[FighterCat57]

I know somebody will say they NEVER get water through their shaft. No matter how hard you try, water seems to find a way in. Put a small piece of sponge under where the shaft enters the boat, next to the motor coupler. This will soak up a small amount.

Yeah, the sponge is a wonderful thing!

I've been putting extra sponges in my hulls and they've saved me more than once!

I plan on putting this one in some really really rough water (ocean surf) so minimal leakage and maximum seal is the goal. Hence the jet drive possibility.

[sailr]

In my bigger boats I put a couple of TAMPAX in there. Works great! You just have to explain to your wife why you have TAMPAX in your car. Haha.

[Jeff Wohlt]

Still easier to explain that than a condom! I used them for radios years ago. Worked great. I tie the tampon to the anntenny tube...LOL

[FighterCat57]

I guess I asked for it. I was asking to protect my shaft and prevent leakage...

OK, Looks like it'll be acceptable to go with a 4mm hard shaft and a sealed rubber boot on a rudder control.

[CornelP]

BTW, the worst leak I had was from a jet drive... the body is plastic or GF and the rigid shaft is just glued or forced in. Two runs later on a brushless, you get a bit of play and loads of water.

[FighterCat57]

BTW, the worst leak I had was from a jet drive... the body is plastic or GF and the rigid shaft is just glued or forced in. Two runs later on a brushless, you get a bit of play and loads of water.

egads!

Maybe I'll just stick with the strut/rudder setup.

[Simon.O.]

The solid shaft in a grease fill stern tube is close to perfect for water tightness, I use them in both of my scale boats and even with heavy astern power there is no water ingress.

The jet drive is still an option. The jet unit can be mounted outside of the watertight compartment. The rear part of the boat can hold the jet unit in a wet area.

A quick sketch !

[Xfactor]

Mc master carr my friend I can tell you expect to pay 100 dollars plus for a sealed flexible motor shaft.