Paul,
The Atomic 4 has thrust bearings on the crankshaft, like most IC engines. For most boats up to 30', the thrust is typically less than 300 lbs, even under full throttle.
Your investigations are pointing out why many people that are doing conversions choose "turn-key" solutions. They all have thrust bearings in the reduction assemblies or in the motor, if direct drive.
SolidNav, Electric Yacht, Advanced Marine, Propulsion Marine and ASMO all have different solutions, but they all accomplish the same objective, a drop in solution to converting a sailboat to electric.
For many of us, paying for someone else to do the engineering and prototyping is worth the investment. For me, I'd rather be sailing. :)
Fair winds,
Eric
Marina del Rey, CA
--- In electricboats@yahoogroups.com, "tartan27hull157" <tartan27hull157@...> wrote:
>
> John, Dennis, et al...
>
> Thanks much for the notes, they are a great help. I am no machinist or engineer but I do like to learn as much as I can and this project is certainly a help!
>
> Dennis, based on your suggestions I did read about the bearings on the SKF site, and I looked at bearings for sale through a half dozen distributors willing to sell at the single-unit level (McMaster-Carr, Grainger, thebigbarningstore.com, Baldor, etc.).
>
> At first I let myself be surprised that no bearing recommendation has emerged on this site, since a thrust bearing seems to me to be as important to the conversion project as motor/controller/batteries.
>
> But then it occurred to me that there isn't any consensus on motor/controller/batteries either. ;-)
>
> I suppose in a direct electric drive system, no bearing is necessary since the mounting hardware that holds the motor down transfers the thrust to the hull. But since many electric conversions require reduction to be efficient, from what I have learned they all require a bearing.
>
> The variety is by no means bewildering, but it hasn't seemed like a simple choice to me so far! A great many of them are not manufactured for the corrosive environment of a boat, so that makes the first step easy; but then there is the choice of flange or pillow block; and I was also able to find some which have a bore to accommodate my 1in shaft, but which are not rated to handle the 1600+rpm I expect to demand. The stainless steel ones seem to vary in price from $60something to $200something.
>
> My ICE (an Atomic 4) doesn't have anything that I would call a "thrust bearing," but that's probably because I am just learning the names for these things. As far as I can tell, the tailshaft emerging from the engine is connected mechanically to the pistons via the crankshaft and some other magic that makes reverse happen...in any case what is on the aft side of the engine is just a flange, called perhaps an output flange, which bolts directly to the prop shaft flange. I suppose technically there must be a bearing where the tailshaft exits the engine, but the two applications are quite different in my mind since the tailshaft is really part of the engine, whereas the pulleys and belts I will end up installing as part of the electric drive system are not part of the electric motor.
>
> ...put another way, the tailshaft is not tabbed to the hull,but the flange mounting plate will be.
>
> Has anyone been particularly happy or unhappy with the bearing they selected?
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> Thanks, Paul
>
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