prop shafts

[learner johnParticipant @learnerjohn78074]

Hi! My boat was  ready for ballasting, so put it in my tank and added my homemade lead shot,as the battery etc  was already fitted decided to give it a whirl just to see the prop going round in water  ( as you do).

  Left in the tank overnight and found next morning it had a list due to ingress of water thro’ the prop shaft. How tight must the nuts be to achieve a decent seal

 at the expense of a free running shaft…what’s the best way to get grease in the tube if this could be an answer.

 

[learner johnParticipant @learnerjohn78074]

[neil hpParticipant @neilhp]

i always mix some vaseline with graphite powder, then spoon it into a syringe with a thin wooden spatula.

remove the prop, and pull the shaft back until it just clears the inside of the first bearing, but is inside the tube to it’s full length.

from the open end squirt the grease into the tube so that it shoots up the sides of the shaft.

rotate the shaft whilst doing this so that the grease fully fillsathe tube and coats the shaft.

once full, press the shaft out through the bearing and re connect the prop.

voi la’

[ashley needhamParticipant @ashleyneedham69188]

Wow.. the old chestnut.

 

Some use grease, oil or nothing. There is no right or wrong answer, at least,to this forum! everyone has their own preference.

 

Some careful spanner work and a few minutes and get as small a clearance as you can achieve. I have used nylon washers in the past to achieve zero clearance but still free running, and/or use a grease soaked felt washer on the inside, the clearance can then be tightened just that little bit more, or less…even, the felt washer acting as a springy seal.

 

I wouldnt worry about a very small bit of water entering, after all, the boat will only be in  the water for a couple of hours perhaps…not  overnight as you tested it.

 

Ashley

[Paul TParticipant @pault84577]

As Ashley says this subject raises its head every 12 months or so and in fact was first covered in the Magna Carta.

 

Dry, full of oil, packed with grease, lubricated with NASA sourced lithium zero grav micro balls, baby oil and KY gel….the list is endless as is the advice that you will recieve either here on the forum or at the lakeside.

 

To reduce the question to its fundamental basis it all depends upon the size of boat, propshaft dia, engine speed and fresh/salt water.

 

So to give better advice we could do with more information about your model (and then we will be able to give some really conflicting views)

 

Paul

[ashley needhamParticipant @ashleyneedham69188]

Paul,  Hello again,   and well put !

 

Ashley

[Paul TParticipant @pault84577]

Hi Ashley

 

Its nice to be back and missfiring on all cylinders.

  

Paul

 

Edited By Colin Bishop, Website Editor on 09/01/2011 10:09:57

[Bob Abell 2Participant @bobabell2]

Hello chaps…..Just picking up the baton, so to speak…..

 

It`s about time, somebody produced a proper engineer`s oilseal?

 

Bob………Eng. (ret)

[David MeierParticipant @davidmeier28154]

I thought you would be plugging the paddle boat models Bob. They don’t suffer leaky shafts do they?

 

David.

[Bob Abell 2Participant @bobabell2]

Hello Dave

 

You`d be surprised, how much water gets in through the paddleboxes….Jeanie Deans has a built in bilge pump!

 

Just noticed your new avatar!

 

Bob

[David MeierParticipant @davidmeier28154]

Hi Bob.

 

I am surprised, I thought that the paddle shaft would be far enough above the water but I guess there is a fair bit of water thrashing about inside the paddle boxes when it is running.

 

I am interested to hear that you can see my new avatar because I can only still see my old one and I have been waiting for the new one to appear. I thought it was time for an updated photo, I always felt the other one made me look cynical which I hope I am not.

 

David.

[Paul TParticipant @pault84577]

Hi David

 

The new image is very clean cut and not at all cynical……even if it does make you look like a certain starship captain.

 

Beam me up scottie

 

Paul

[David MeierParticipant @davidmeier28154]

Hi Paul.

 

It is nice to see you back again.  What is this about a starship captain? I can’t spock the resemblance myself.

 

David.

[Paul TParticipant @pault84577]

Hi David

 

Whilst you might not see any resemblance I shall Klingon to my belief that you and capt Pickard are twins.

 

Paul

[David MeierParticipant @davidmeier28154]

Sigh —————————–ince friction.

 

David.

[Paul TParticipant @pault84577]

On a life long mission to seek out new models and new lakes to sail them on, to boldy go where model boaters have never been before.

 

 It sounds like a really bad programme on the Discovery Channel.

 

[ashley needhamParticipant @ashleyneedham69188]

On its first trip out the NELSON did indeed let in water through the propshafts, a bit, or at least, a few mm overall, over 2 hours almost..despite being nipped up to the point of binding. They are nylon bearing/stainless shaft types and are entirely below the waterline (no grease).

 

I sucked the water out with my syringe and let the top off so it would dry out. However, as the inside is painted with fibreblass resin, there is no problem, and I am not proposing to do anything about it.

 

Ashley            so there

[B BParticipant @bb42502]

Good snug Vesconite bearings and 50/50 mix of bearing grease mixed with 0w50 oil which = a nice thin grease lubricant. Bingo a proshaft that turns with very little resistance and no water ingress. How about adding a lubrication tube on the propshaft tube. Full steam ahead captain Kurk and Dr Spock..

[phill dParticipant @philld]

Hello shipmates

 

What i have used in the past with high powered ic engines is the old white waterpump grease.

Now if using this on electric boats i would think it would work even better than high revving ic engines.

 

Many people use this on full size boats for their Glands ( bearing seal glands that is).

 

No shaft that sits below waterline will ever be completely sealed, full size boats have

auto bilge pumps for this very reason.

 

you can always pack a shaft with cotton wool smothered in grease to give a better seal, but

like said above,models are not in the water for too long.

 

I have a so called sealed watertight shaft in one of my boats, and even that lets a certain amount of the wet stuff in.

 

 

 

 

phill   

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