The elbow
caused the fire
Brief History: This
situation involves an eleven year old vessel powered by a twin
diesels. The engines had approximately twelve hundred hours of operation
logged. There was an engine room
fire just a few miles from port. The fire extinguished itself because
the hatch to the engine compartment was kept closed. Luckily the natural
ventilation to the engine compartment was minimal and not sufficient to
support any more than the initial blaze. When the operator noticed smoke emanating
from the hatch he shut down both engines and called for a tow.
The
operator was told by the seller that the parts in
question, "the exhaust elbows", had been replaced just a few
years earlier. While we do
not have a photo of the "before the fire" elbow, we did clean the soot off the
elbow and it is pictured at the bottom this page attached to the turbo.
The red arrow indicates the location of the material failure. From the outside view It looks pretty
good, so it probably appeared in very good condition before the fire.
The three photos above
indicate severe oxidation (rusting) of the cast iron element that failed,
(it broke off from the exhaust elbow), allowing extremely hot exhaust gasses to escape into the engine
compartment and cause the fire. The rusted cast iron was not noticed by
the owner, who did his own maintenance, because it was hidden by the
stainless clamp used to secure the elbow to the turbo component.
The three photos below are
of the elbow which when new was an integral part of the ring in the
photos above. The red arrows indicate areas of complete oxidation. The
red arrow in the center photo indicates complete loss of the inner liner
of the water jacket. The photo, below right, shows an area that was covered
by the rubber exhaust hose. This area is also completely oxidized, and
could not be inspected because the exhaust hose covered it.
The photo (below) shows
the two
components that were joined by the stainless clamp and rusted iron in the first photos as they
might have been seen before the fire. The red arrow indicates the
placement of the stainless clamp that hid the rusted cast iron
joint that broke free.
The material pictured (bottom
photo) is rusted iron scale. It is the remnants of the water jacket
of the elbow.
