Help, Don't know boats but how do I maintain water-tight motor drive?

[Peter W]

Hi all,

I'm sure this has gotta be a simple answer hopefully for all that frequent the Boats forums.

What I would like to know is how you guys maintain drive through a bearing assembly without water leaking through to an electric motor/inside of the boat.

I know boats use long extended shafts but for my application I require the drive to be maintained only on the motor shaft itself, i.e. no 'boat-like' extension shafts

I will mention also there will be a few kilos of positive water pressure acting on any bearing/device.

So what is the best way to accomplish this? The use of a single bearing? I'm really not sure!

Thanks all,

Pete

[Ghost 2501]

well i fill the tube with grease then insert the shaft, that keeps most water out.

post a pic of your boat :)

[Peter W]

sorry I wasn't clear, I don't have a boat but want to implement a water-tight principle

[Boathead]

Hello Pete,
Contact Phil at Vac-u-Boat, http://www.vac-u-boat.com/Welcome.html

A year or so ago he was working a drive system that used a set of three magnets on a disc on each side of a drive. He had quite a bit of space including 1/8'' plexiglass between the discs and it took a good amount of force to make the drive slip.
Something like that may work for you depending on how much space you have and what your load is.
I hope this helps or maybe gives you some other ideas. :)

Good luck with your project!!

Doug

[Peter W]

yes I had considered a magnetic drive of sorts but didn't really know how to go about it.

In a prototype I made I used the actual front bearing of the electric motor, suprisingly it let no water past If I remember correctly! Not sure it's good practice tho:)

[Boathead]

yes I had considered a magnetic drive of sorts but didn't really know how to go about it.

In a prototype I made I used the actual front bearing of the electric motor, suprisingly it let no water past If I remember correctly! Not sure it's good practice tho:)
I would think you would be ok as long as the assy was balanced.
Maybe Phil can send you a picture of what he did. I looked but couldn't find one.

Doug

[Ghost 2501]

magnetic drive, think fish tank pump

[flufy]

Hi i think Subtech do seals that some peaple use in there subs these are made to take the pressure.
Here is the link to UK seller.
http://www.rcmodelsubs.com/acatalog/Our_Online_Catalogue_SubTech____Submarine_Hardware _283.html

they are a lot smaller than normal r/c stuffing box's

[Umi_Ryuzuki]

If you just want to use a plain old stuffing tube, you can buy, or scratch build one for your self. Most of these are good for up to a few feet below the surface of the water.

http://www.rcgroups.com/forums/showthread.php?t=437771

Any deeper, and I would consider the magnetic suggestions, or perhaps a dual stuffing tube arrangement, where the first tube stops inside a water tight chamber, and the second tube brings shaft into the motor area.

[Tollytime]

Try www.mikessubworks.com. He has seals for stuffing tubes that might help. Click on Seals under Hardware or call on the phone and ask.

[fleetmaster]

Why not just try Boca Hybrid sealed bearings,more efficient than bushings.