Quote:
Originally Posted by rigspelt
2. Every two years of average summers in clear water.
3. Every 200 hours (= 800-1000 miles under power), more often in sandy water.
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The "200" hours rule of thumb in my list troubles me most. I don't have any technical failure data to base it on, just a sense of what long range cruisers have said from their own experience. The idea is to have a rule of thumb for changing the impeller more frequently than every two years, for example during a long summer of coastal cruising.
I'd be curious to know the typical seasonal engine hours for average North American sailboaters who just start their engines to get out to race course 1-2 times a week, plus once or twice on weekends for day trips, plus a summer holiday cruise 200 miles round trip. Double that to get two seasons in clear water. But there are so many variables on a long cruise: number of days engine runs per week, condition of the water, water temperature, idling time versus cruising time under load, etc.
Guessing at typical engine use in freeze-up communities (obviously highly variable):
Half hour per race night x 2/wk = 1 hr/wk, total race season at 1.5 nights/wk x 16 wks = 24 hours.
One hour per weekend day trip = 1 hr/wk, total summer season at 1 trip/weekend x 16 weeks = 16 hours.
Summer holiday, 2 weeks, 300 mile round trip in 10-60 mile hops, travellng every 3 days = maybe 30 hours (highly variable)? Probably good idea to pull the impeller and check it prior to departure and on arrival home from a summer cruise.
Total = 70 hours. And my guess is that most sailboaters put on a lot fewer engine hours than that, so this probably is conservatively high. Most marina-based power boaters think of 50 hours as a slow summer typical of most boaters, and 200 hours as a moderate use summer including a holiday cruise.
Two such seasons = 140 hours.
So a conservative sailor might use 100 hours (400-500 miles), others might use 200 hours (800-1000 miles).