Here's an example of a type of bearing that works:
http://www.mcmaster.com/#flange-mounted-ball-bearings/=am3si1
There's no rating listed for thrust loads, but they can handle a significant amount due to their grooved races. You would normally use two of them to hold the shaft rigid and parallel to the motor shaft. I forgot to mention thrust loads in my previous post. I don't think you mentioned what kind of boat you've got, but a typical 25-30 ft. displacement boat at hull speed will top out at a maybe few hundred pounds. For example my Albin 25 takes a little over 200lb to push at 6.3kt. She'll do that pulling 5.28KW (7hp) from the batteries. As for lubrication, a good sealed bearing as above will last for years without any maintenance, but they do have zerks so you can give them a squirt once in a while if it makes you feel better.
I've used food-grade bearings with plastic flanges, but for their electrical isolation properties rather than corrosion resistance. If you go that route, look carefully at the rpm and load ratings. Some are pretty low. Not sure why, but perhaps it's due to the plastic getting soft as they warm up.
Cheers,
Jim McMillan
--- In electricboats@yahoogroups.com, "John Green" <v_2jgree@...> wrote:
>
>
>
> Hi, John,
> Any pics that you have would be interesting to see. I am always impressed with pics of electric drives because everything is generally so clean and easy to see. Not so with (used) ICE motors.
> My own thinking is to start with a plate, and have maybe two right angled triangles made up of angle iron, that bolt to the 4 bed mounts and to the plate. This will triangulate the support. The hypotenuse angle piece would be removable for access. My actual design as such would be dependent upon the motor(s) and belt arrangement, as I would want belt drives. In my case, I am expecting the electric to be used more for docking only, so it might turn out that I use quite low powered motors, and might have to reduce the gearing on them, and belts are an obvious easy way to do this.
> The interesting thing is that it can probably be quite lightly built, if it is considered how overpowered a regular ICE installation seems to be.
> George, I asked the same question a while back about the bearing. The example given by a group member, I forget who, was for a flanged industrial style bearing, I believe it was self-centering, with a bore to match the prop shaft diameter. I believe from memory that the specific example given was for one that had some kind of rust resistance, I forget whether it was stainless parts, or plastic coating. My interest at the time was whether the bearing used had thrust capability, like, was it specifically designed for large thrust loads, and the example given was just a regular ball bearing, with nothing added for thrust. What I am trying to convey is that from what I gathered, although obviously the bearing is of critical importance, it is in practice nothing extra-special, just a regular industrial 2, 3, or 4 bolt flange cast iron body self-centering ballrace type bearing, if the rust proof part is ignored.
> This actually makes sense when you think of a Minnkota electric outboard having 30 pounds or so of thrust, and being able to move relatively large boats. Most of the load is going to be radial, (due to turning torque loads) just as is the case with an industrial conveyor belt roller. My only concern would be to add a means of greasing after every use, and collection of old expelled grease.
> The rust resistance can be easily obtained by selecting a bearing used in the food processing industry, where hosing down is a regular requirement. Either way, these are not 'retail' items, nor are they 'marine' items, so the prices should be fair.
>
> John
>
>
> Re: Re -Main mounting plate needs.
> Posted by: "John Raynes" johncraynes@... eboatdrives
> Date: Sat Jan 15, 2011 6:04 am ((PST))
>
> John,
>
> FYI, I installed a flange thrust bearing attached to a plate and secured to
> both sides of the engine beds allowing the motor the single job of turing
> the propellor shaft. I can send a picture if you like.
>
> John Raynes
>
> On Sat, Jan 15, 2011 at 8:44 AM, John Green <v_2jgree@...> wrote:
>
>
>
> --
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