>From my experience engine room fires are two, electrical and fuel.

Fuel fires are rare.  Diesel fuel is hard to get to burn.  The only ER fuel 
fire I have had experience with involved a fuel leak spraying onto a 
supercharger I was told.  But the relaxed attitude of that boat's occupants at 
the time lead me to think that arson may have been involved.  I have personally 
sat in an inch of diesel in each of my three fuel tanks with a propane torch in 
my hand replacing the sweat elbows in my fuel suction lines.  Fuel was all over 
the pipes.  The only time I got a flame to appear was when I overheated one of 
the pipes and I simply blew it out.  The best way to get diesel to burn is to 
get it to wick onto something, then light the wick.  I don't believe there is 
anything in my engine room that is hot enough to ignite diesel oil.  The 
exhaust elbows coming from the exhaust ports into the manifold run around 230 
to 360 degrees depending on rpm's.  I measured them frequently lately with a IR 
thermometer to set my injectors.

An electrical fire is the most common engine room fire.  I have seen two boats 
sink after electrical fires began.  The most obvious defense is to have a way 
to cut off all electrical power to the engine room.  As long as the short 
circuit remains and the electricity flows the fire will continue.  I have a 
large circuit breaker (300 amps) that stops all power from the house batteries. 
 

Once the current is off, a water hose should cool off the smoldering insulation 
which typically does burn well but goes out easily once the power is shut off.  
Perhaps a garden sprayer would be the ticket.  Maybe a special fire pump or an 
anchor washdown pump with a long hose available.  I do have a foam fire 
extinguisher I got at Home Depot that I have great faith in.  

Smoke is a big problem.  It is hard to fight a fire if you can't see it.  The 
skipper of one of the sunk boats from an ER electrical fire said to the 
newspaper that he opened the ER hatch and all he could see was thick black 
smoke.  He shut the hatch and hollered to be rescued.  The boat burned to the 
waterline and sank.  Although I haven't finished the project yet, I have the 
parts to make a big (auto radiator 12 VDC) fan to blow air into the ER so I can 
see what I am doing to put out the fire and supply me some breathable air.

And don't tell me I am fanning the fire by blowing air into the ER.  Fires 
don't need as much air as most folks think.  There was a classic case of a red 
glowing 40' container on a APL ship.  It contained charcoal.  I am sure the box 
was stuffed full of charcoal but there was still plenty of air in this steel 
box to do the job.  The crew set up fire hoses to play on the container and APL 
did not carry any more charcoal.  Incense was considered a hazardous cargo when 
I was with them.

Switches/breakers on the starting battery has been covered in earlier threads.  
Basically, the circuits are so short and the currents so high during normal 
use, that a breaker would not work.  A remote switch at the battery would be a 
good thing I suppose, but I have never seen one that would handle the one 
thousand amp starting load on my boat.  


But as for the seawater hose, I use the black stuff with a spiral wire in it.  
Gates Green Stripe is the best, they say.  (The best way to cut the stuff is 
with a thin wheel in an angle grinder.)  I have never had a problem with any of 
it.  I did have a problem with a 90 deg elbow I had cut out of a radiator hose 
from NAPA by cutting the elbows from a piece of hose made for a particular 
automotive application.  It was much thinner and lighter that the Gates 
straight hose.  

Another thing, the seawater hoses are full of seawater which will have a large 
cooling effect.  What was that astonishing demo, something like boiling an egg 
in a paper towel with water in it held over a fire?  The water soaking the 
paper towel can get no hotter than 212 deg so the paper cannot burn.  

If the hoses get hot enough to burn, you will probably have already lost the 
battle. 


Norm
S/V Bandersnatch
Lying Julington Creek FL


----- Original Message ----- 
From: Ballantyne, Merrill 
To: [email protected]
Sent: 11/14/2007 1:09:55 PM 
Subject: [Liveaboard] Raw Water Intake Hose


What type of hose do people recommend for engine raw water intake?  The engine 
is a perkins 4-108, with 1-1/8” dia. hose barb on the pump.
 
I am looking at two choices:  one is a plastic helix reinforced PVC hose with a 
smooth interior and exterior, similar to sanitation hose except it is clear 
with a black helix, not white.
 
The second option is either wire reinforced or non reinforced double wall 
trident hose which is essentially the same as exhaust hose. 
 
The pro for the first one is that it is more resistant to oils than the rubber, 
but the rubber is more resistant to heat.
 
Please let me know what you all recommend.  
 
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