Yes, of course it's (mainly) a function of motoring hours and I think Jose agrees. I've been motoring about 400 hours a year lately, but my bottom paint lasts about 3 years, so I'm keen to have a long-lived solution.
Super that you never get water in the oil. From posts to this forum that seems to be the exception, but more power to you!.
I do think there are other factors involved here, such as different propellers in differing states of maintenance giving differing amounts of vibration; alignment of the drive shaft, condition of engine mounts etc., all playing on vibration and the efficacy of the lip seals. The hardness of the bearing and orientation of the rotary shaft seals are certainly key factors, but if you add it all up there is likely a wide variation between all our boats.
So, in your case, "if it ain't broke, don't fix it" - keep it like the Captain divined and Admiral CW Bill proselytizes! (Can't recall if that was one in and two out as you noted or two in and one out, but whatever.)
---In amelyachtowners@..., <milesbid@...> wrote :
I don’t understand why two years has any significance. The original Amel instructions were to change the wearing out bearing every 650 hours. How much the bearing wears is a function of engine hours not time. Any valid comparison test would need to for the same number of hours at the same engine speed.
For over 5000 engine hours, I have changed the wearing out bearing using lots of silicone grease and following the Amel instructions of the first bearing facing in and the outer two bearings facing out. I have done this (or Amel has done it) every 650 hours or so. I have never had any problem of water in the oil or loss of oil. I have had my boat since it was new and I learned early on that everything that Amel does or recommends is for a reason.
s/y Ladybug, sm 216, Le Marin Martinique