Single vs Trwin
I doubt there is a 1000x improvement in the reliability of a twin over a
single.
Similar propulsion systems operating in the same environment will be subject
to the same failure rate. I am not sure how you would calculate the
probability of both systems failing at the same time -- but the question is
more difficult than it seems.
Different owners maintain there systems differently. Effective maintenance
and knowledge of your boat' system is the largest factor in affecting
reliability and safety. If you don't know how to maintain one engine, two
engines will not give a greater reliability.
Beebe did it all on a single engine. It is all about knowing your limits and
making intelligent choices.
Dr. Al
E-Mail: almiller@n-jcenter.com
At 03:30 PM 4/26/99 -0400, you wrote:
I doubt there is a 1000x improvement in the reliability of a twin over a
single.
Similar propulsion systems operating in the same environment will be subject
to the same failure rate. I am not sure how you would calculate the
probability of both systems failing at the same time -- but the question is
more difficult than it seems.
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The question is so difficult that I can't imagine two weak links breaking
at exactly the same time. In fact I think it is a physical impossibility.
AL
.
Captain Al Pilvinis "M/V Driftwood"--Prairie 47
2630 N.E. 41st Street
Lighthouse Point, Fl 33064-8064
Voice 954-941-2556 Fax 954 788-2666
Email - CaptainAl@Juno.com
Website http://home.earthlink.net/~yourcaptain
Al
<I doubt there is a 1000x improvement in the reliability of a twin over a
single.>
And in that doubt you demonstrate that you are likely not qualified to make
the selection. You should know whether that number is correct, or not
correct, before you make such a selection.
In fact the number is reasonably correct. A range from 500x to 10000x is
possible give the numbers tossed around for the reliability of a singe
engine. The calculation for the reliabilty of two redundant things taken as
a pair is simply to multiply the failure rates.
<<Different owners maintain there systems differently. Effective maintenance
and knowledge of your boat' system is the largest factor in affecting
reliability and safety. If you don't know how to maintain one engine, two
engines will not give a greater reliability.>>
Given the same maintenance strategy and level the advantage of twins will be
there. If the engines are badly maintained the advantage will be reduced
but is still likely to be orders of magnitude.
<<Beebe did it all on a single engine. It is all about knowing your limits and making intelligent choices.>>
The guy in Mag Bay got there too. Kids sail to Hawaii by following
contrails in 20 ft. boats. The knowledge of limits and making intelligent
choices may be over-rated. Everybody gets there most of the time.
Jim
At 03:50 PM 4/26/99 -0700, you wrote:
Al
<I doubt there is a 1000x improvement in the reliability of a twin over a
single.>
You wrote
<<Beebe did it all on a single engine. It is all about knowing your limits and making intelligent choices.>>
The guy in Mag Bay got there too. Kids sail to Hawaii by following
contrails in 20 ft. boats. The knowledge of limits and making intelligent
choices may be over-rated. Everybody gets there most of the time.
Jim
=--
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Jim---------I got there for 22 years with a single, coastwise cruising and
didn't worry to much.
Now we spend a lot of time in the Islands so I am much happier with twins.
I have a keel that goes about 8" below the props and rudders and really
aren't to worried about putting the Driftwood aground while looking for a
passage into that unreachable lagoon. While others are anchored outside we
are inside all by our selves.
I did the same thing with my single. Twins have not changed my boating
methods. You have to pick the boat with the right underbody configuration.
AL
.
Captain Al Pilvinis "M/V Driftwood"--Prairie 47
2630 N.E. 41st Street
Lighthouse Point, Fl 33064-8064
Voice 954-941-2556 Fax 954 788-2666
Email - CaptainAl@Juno.com
Website http://home.earthlink.net/~yourcaptain