Failed the bathtub test!

[Nigel Taily 1Participant @nigeltaily1]

Hi,

I popped my almost-finished wooden hull in the bath tub to check for leaks.

And it leaks!

Water is coming up from the propshaft sleeves. They don’t have the prop shaft in yet. Just the hollow “outers”

So the question is, will the grease and the shaft act as a seal against the water?

Am I worrying about nothing?

Will it be OK if I only go forwards?

My reasoning being that it will be similar to dinghy sailing where the self baler drains the boat.

I wonder if I should start again with much longer shafts that exit higher above the waterline.

But starting again by removing the existing ones is a fairly big task.

It’s a wooden 34″ Huntsman loft-find from Precedent.

[Ray Wood 3Participant @raywood3]

Hi Nigel,

Yes when the shafts are installed that will stop the water coming in 🙂

You don’t need to grease the shafts either just light oil before a run .

Regards Ray

[Richard SimpsonParticipant @richardsimpson88330]

Nigel, It’s not really leaking!  You put the hull in the water with four holes in it.  If you had pushed it down a bit further a little water possibly could have come up the rudder tubes as well!

When you fit the shafts in the tubes you are aiming to have just enough clearance for free running and, preferably with a thrust washer on either end to A) Transmit the thrust either way and B) Help to seal the end.  There is always a possibility of an occasional drip but oil in the tube will help prevent it and the thrust washers will also help.  Sealed bearings are also a better seal than a plain bush but they can be difficult to get hold of in very small sizes and they put slightly more load on the motor so are defenately not favoured for performamce boats.  I usually put oil in the tube and a smear of vaseline on the thrust washer.

If you look at my Ben Ain thread I fitted a sealed ball bearing on either end of the shaft because the shaft is horizontal and way below the water line.  Also a steam engine doesn’t have any problem with a little extra drag from the seals.

[Nigel Taily 1Participant @nigeltaily1]

That’s a relief!

Thanks very much for the advice.

I do have some marine grease but that does get quite solid after a year or so.

I think that I will use the white grease in my toolbox. A touch of light oil before each outing should be good.
Thanks very much everyone

[Colin BishopModerator @colinbishop34627]

Nigel,

Have a look at this feature article by Glynn Guest on Drivelines. The diagrams are at the end. I think you will find it very useful.

Drivelines

Colin

[ashley needhamParticipant @ashleyneedham69188]

<p style=”text-align: left;”>Opinions vary, but using nylon washers either end and adjusting the nuts until there is absolutely no play in the shaft is the way to go.</p>
Bottom bearing is water lubricated. Inner one just needs one drip of oil before each run.
<p style=”text-align: center;”>Ashley</p>

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