Hi Jim,
Just to be clear I am not using a separate thrust bearing. I'm using the Lynch motor bearings to take the loads, which there are two off in the motor of the types below,
3204-2RS or the 3204-2Z.They differ I think by seal/friction/lube.3204-ATN9 SKF Double Row Angular Contact Ball Bearing - Polyamide Cage :: BearingBoys.co.uk
I ran through some basic calcs with SKF for a 3204 type ref
http://www.skf.com/uk/products/bearings-units-housings/ball-bearings/angular-contact-ball-bearings/double-row/index.html?prodid=125002204&imperial=false
Shows static of 20kN and dynamic of 12kN but does not account for operating conditions.
Even in my case of estimating an axial shock load worse case surfing down waves past hull speed gives gives say static load of 3kN (675lbf) axial on shaft. I think on say a 10m sailboat with locked 3 blade 14" prop gives a drag of about 45kg (100lbf) at 7 knots when sailing which is nearly 1/2 the drag of the hull at that speed?
I called SKF and we used
http://webtools3.skf.com/BearingCalc/selectCalculation.action
My calcs/results below. The EP warning if I recall correctly from my apprenticeship means Extreme Pressure (grease/oil)
Bearing life : 3204 A-2Z/MT33
Results
| L10mh SKF rating life, operating hours | 2310 hour |
| aSKF SKF life modification factor aSKF | 0.114 |
| κ Viscosity ratio | 0.17 |
| P Equivalent dynamic bearing load | 4.04 kN |
| ηc Factor for contamination level | 0.0569 |
| ν1 Required kinematic viscosity for κ=1 | 153 mm2/s |
| L10h Basic rating life, operating hours | 20200 hour |
| L10 Shielded bearing grease life 130 | 77500 hour |
| C/P Load ratio | 4.95 |
Warning
| Viscosity ratio κ=0.17 is less than 0.4 - a lubricant with EP additives should be considered. t |
Input parameters
| Fr Radial load | .5 kN |
| Fa Axial load on bearing | 3 kN |
| ni Rotational speed of inner ring | 100 r/min |
| Bearing operating temperature Bearing outer ring | 70 °C |
| Grease used in the bearing Select from list | MT33 |
| Viscosity at 40 °C | 100.0 mm2/s |
| Viscosity at 100 °C | 10.0 mm2/s |
Jim - I can't say for 100% certain what is right for you. I'm happy with what I have. At the end of the day, I'm not commercial, just one guy with a limited budget and no funded R & D dept. In that, there is risk.
Personally if I were in your shoes I'd go for a conventional thrust bearing arrangement. I think Cal is commercial so maybe he knows what is best for you but I'm not clear what he has built. I have no experience of Motoenergy motors, only my system which I have documented with my learning curve on a public Facebook page.
John
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