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Subject: Re: TWL: Re: Natural versus Turbo
From: Alex Hirsekorn (alexh@XXX.XXX)
Date: Fri Sep 07 2001 - 00:40:00 EDT
----- Original Message -----
From: "Michael Maurice" <mikem@XXX.XXX>
> [snip]
> I am inclined to think that turbo's are not a good idea in long range
> single screw cruising boats.
[snip]
Hi Mike,
You make a very important point here (One that I think you've raised
before). Choosing any piece of equipment whether it's Turbo vs. NA, WAAS vs.
Diff vs. neither, Furuno vs. Raytheon, etc should be based on facts and the
operators understanding of how those facts fit with his or her own needs.
The importance of how these choices are made increases geometrically with
how far you get from outside assistance.
A turbocharger could be regarded as one more thing that could fail and, as
such, is something to be avoided.
Personally, I disagree with that notion. OTOH: I have no intention of
crossing any oceans so my opinions are automatically suspect.
Of course, I've never been one to allow a suspect opinion to stop me!
Can a turbocharger fail? You bet! The most common failure modes for these
things won't cause the engine to quit however. Usually you would find that
your 200HP engine suddenly bacame a 150HP (or less) engine. Inconvenient bu
not normally life threatening. If you were to find yourself offshore facing
some really bad weather then reduced power could be more serious but it's
fairly common for recreational trawlers to be somewhat overpowered to start
with so maybe this isn't catastrophic either.
The scenario that you describe with a broken oil line spraying lubricant
into the intake is unlikely but possible. If that happens one of three
things will result; You'll start burning that oil and the engine will be
running badly and belching blue smoke; The engine will simply die; The
engine will run away. That last one is the most serious (well duh!) but it's
generally accepted that the prudent skipper will have a plan for dealing
with it and getting the engine shut down. Once the engine is shut down the
options are fairly simple and should be within the skills of anyone who
ventures away from outside assistance. One fix is to either block or
redirect the broken line so that the oil either stays in or is returned to
the crankcase. Another possibility would be to have replacement oil lines in
the spares locker. Finally, the ultimate fix would be to have a replacement
turbocharger on board. Obviously that could be fairly expensive but it would
provide an answer to virtually any turbocharger problem. The other downside
is that, with the overall reliability of today's turbocharged engines, you
are statistically likely to have that spare turbo for a LONG time.
Wil raised the idea that a turbocharger is a far simpler mechanism than an
infector system. I don't know if he meant to say that one is more
troublefree than the other and I'm in no position to argue either way. I
will say this however: A turbocharger that's on the fritz is going to be far
easier to fix than an injector system and it's more likely that a turbo
problem will let you at least limp home.
It must be emphasized that the chances of any of these things happening on a
well engineered and well maintained engine are incredibly small. [Science
fiction writer Larry Niven has a saying for those who cross oceans without
well engineered and well maintained systems; "Think of it as evolution in
action.]
When all is said and done Patrick had the best arguement in favor of
turbocharging; We really don't have much choice these days!
Reliably Yours,
Alex
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