[TheForge] costs of ownership question

[Andrew Vida]

On 9/11/2012 6:45 AM, terry l. ridder wrote:

>

> the longer the piston rod the more the rod would have the ability to
> bow.

	Um... no.  There is a thing called "rod angularity" and the longer the 
rod, the smaller the lateral thrust vector driving the piston into the 
cylinder wall.  The longer the rod, the LESS likely it is to bow, which 
is one reason diesels tend to have long connecting rods, particularly 
when compared with gas engines.  This is especially true of very large 
engines serving as prime movers in large ships.  Once in-hull, those 
things go nowhere usually until the ship is scrapped.  Pulling an engine 
back OUT of a large commercial ship is, at the very least, 
hernia-initiating in terms of cost and impossible in some cases without 
scrapping the vessel.  Try getting the engine out of a cruise ship, for 
example.  You would literally have to split the vessel in two.  By the 
time you paid for that you could build a new ship and probably have a 
few dollars left over.
>
> this old marine mechanic suggested that if possible rotate the mounting
> of just one of the engines 90 degrees and see if the wear on the cast
> iron sleeve also rotates 90 degrees. he said that would point to
> external magnetic fields causing the excessive wear on the engines.

	I won't call it impossible, but you're right - that is a pretty weird 
concept.  I would think the EMF would have to be pretty significant to 
have such an effect... but maybe it is true.