do you run the engine blower all the time ?

I bet a lot of people leave the batteries on and so not think of turning off on the larger gassers. I used to have everyone off our 340. Batteries off, fuel, blowers on. Pay attendant, batteries on, start boat, finally add people.

Now with diesel: pull up, fuel, leave. Blowers to keep ER cool on really hot days while sitting in slip waiting on our guests.


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Hmmm..... news to me. I've never turned my batteries off when fueling. What about those with a single battery and no switch? I have dual batteries with the switch under the bench seat so it would be easy enough to turn off the batteries.

I don't run the blower when fueling but honestly, I don't have my guests disembark when I need to stop for fuel. 90% of the time I will have the boat gassed up and ready to but the few times I've stopped for fuel with guests I just turn off the boat and let the attendant fill it. I then turn on the blower and start the boat after completing the transaction.
 
based on this topic I changed my usage and ran my blower when underway and also left the switch in the on position when I killed the battery switches - that way I know I won't forget as I (may have) in the past
 
I must admit I haven't been turning the batteries off but I do turn the blowers off.

I also have all passengers off the boat and one of them next to the emergency fuel shutoff on the dock (as we are required to do).

For what good it might do I have a fire extinguisher in nearby reach also.
 
I'll give an opinion here and qualify it as an engineer who develops systems for propellant storage and transfer in the space launch business. Electrical systems are designed and operated to the National Fire Protection Association part 70 which is the National Electrical Code (NEC). The NEC goes to great length to outline electrical systems to be used in and potentially in flammable and explosive environments. Management of arcing and sparking devices is the principal tenant of the code. Arcing and sparking devices in the boating world are things like alternators, switches, breakers, motors with commutators and brushes, light fixtures, solenoids, relays, and the like. These devices as they cycle and operate can produce arcs that are above the ignition point of a potential stoichiometric gasoline vapor mixture. Now you will find the AYBC pretty much parallels the intent of the NEC and for the most part our boats are to the AYBC.
The battery switch is an arcing and sparking device however it should be rated to be explosion proof but no doubt I wouldn't trust it. The battery switch is for the most part open to the engine compartment as the wires run from it to the batteries. I would not in any way cycle the battery switch after fueling and take the chance of it or it's wiring initiating an arc. It is much more stable being left on. The engine room blowers are rated devices and the switches are at the helm which is well away from the engine room environment. Normally, the engine compartment blowers and bilge pumps are not switched by the battery switch but with trailered boats I'm not sure and in my opinion I'd play it safe and not mess with that high energy battery switch.
For gasoline boats with enclosed engine compartments I think best to operate the blowers during fueling. The boat's ignition switch which is another device on the helm must be in the off position; this switch manages many of the arcing and sparking devices on and around the engine. If you have a waste system like Vacuflush there are switches and motors usually in the engine compartment; unless you can be assured all of these devices are rated it's best to turn that systems breakers off. The generator is a no brainer; shut it down.
Probably, most important is keeping up on the maintenance and inspection of the boat's fuel system and be assured the chance of a fuel leak is minimized.
The bottom line here is common sense.
 
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ttmott said:
I'll give an opinion here and qualify it as an engineer who develops systems for propellant storage and transfer in the space launch business. Electrical systems are designed and operated to the National Fire Protection Association part 70 which is the National Electrical Code (NEC). The NEC goes to great length to outline electrical systems to be used in and potentially in flammable and explosive environments. Management of arcing and sparking devices is the principal tenant of the code. Arcing and sparking devices in the boating world are things like alternators, switches, breakers, motors with commutators and brushes, light fixtures, solenoids, relays, and the like. These devices as they cycle and operate can produce arcs that are above the ignition point of a potential stoichiometric gasoline vapor mixture. Now you will find the AYBC pretty much parallels the intent of the NEC and for the most part our boats are to the AYBC.
The battery switch is an arcing and sparking device however it should be rated to be explosion proof but no doubt I wouldn't trust it. The battery switch is for the most part open to the engine compartment as the wires run from it to the batteries. I would not in any way cycle the battery switch after fueling and take the chance of it or it's wiring initiating an arc. It is much more stable being left on. The engine room blowers are rated devices and the switches are at the helm which is well away from the engine room environment. For gasoline boats with enclosed engine compartments I think best to operate the blowers during fueling. The boat's ignition switch which is another device on the helm must be in the off position; this switch manages many of the arcing and sparking devices on and around the engine. If you have a waste system like Vacuflush there are switches and motors usually in the engine compartment; unless you can be assured all of these devices are rated it's best to turn that systems breakers off. The generator is a no brainer; shut it down.
Probably, most important is keeping up on the maintenance and inspection of the boat's fuel system and be assured the chance of a fuel leak is minimized.
The bottom line here is common sense.
Click to expand...

Excellent explanation...your advise make the most sense to me.

To summarize:
1. Engine off
2. Ignition set to off
3. Generator off
4. Leave battery switch alone (if it's on, leave it on. If it's on 1, 2, 3, etc, leave it there)
5. Blower on
6. Follow other local ordinances
 
TTMOTT brings up what I was going to say about the battery switch. Trust nothing .
But I disagree on running the blowers while fueling . ANY VAPORS OUTSIDE WILL BE BROUGHT INSIDE !

BLOWERS should be off 100% while fueling. I'm still old school and pop the hatches after fueling on my lil boat.

Rob
 
Robski97 said:
TTMOTT brings up what I was going to say about the battery switch. Trust nothing .
But I disagree on running the blowers while fueling . ANY VAPORS OUTSIDE WILL BE BROUGHT INSIDE !

BLOWERS should be off 100% while fueling. I'm still old school and pop the hatches after fueling on my lil boat.

Rob
Click to expand...

I could be wrong but the blowers are "blowers" -- they blow the air out of engine compartment. They don't suck in air from the outside and blow out the air from inside. Unless the blower's wiring is defective, there should be no risk of arcing if the blower is already on before fueling. Once the blower is running you just have current flowing to the bower motor and not creating a spark.
 
Blowers exhaust fumes out of the lowest parts of the bilge but sucking them out. Naturally a back pressure is created and fresh air will fill the bilge. If there are gas fumes at the fuel dock they "should" settle to the lowest point which would be the water surface. That is why the air intake vents are generally at a much higher point than water level (usually as high as possible). Fresh air can also fill the bilge from the cockpit if the hatch is open too.

-Kevin
 
Tonka Boater said:
I could be wrong but the blowers are "blowers" -- they blow the air out of engine compartment. They don't suck in air from the outside and blow out the air from inside. Unless the blower's wiring is defective, there should be no risk of arcing if the blower is already on before fueling. Once the blower is running you just have current flowing to the bower motor and not creating a spark.
Click to expand...

believe you're wrong. they suck in fresh air from side of the hull (belive the starboard side) and blow out the port side. that's how.it.was on my 170 and also appears to.be the case on my 270,
 
Black Valkyrie said:
believe you're wrong. they suck in fresh air from side of the hull (belive the starboard side) and blow out the port side. that's how.it.was on my 170 and also appears to.be the case on my 270,
Click to expand...

That seems odd to have the fresh air intake on the starboard side since that's the side that most boats fill from. There is a fuel tank vent on the forward starboard side but that's not a fresh air intake and has nothing to do with the blower or ventilating the engine compartment. Regardless, as was previously noted, even if the ventilation system sucks in fresh air it wouldn't be an issue since the intake would be up high and the gas fumes sit at the water level because they are heavier than air.

This whole discussion has me curious so I'm going to do some research.
 
I am certainly no expert on this but from my limited experience I have seen both configurations.....

some older boats are configured to have the intake air for the bilge blower be supplied by a duct that attaches to a side vent in the ER that brings in fresh air.....the blower output duct is directed towards the bilge...the blower provides a positive pressure in the ER that forces the fumes from the bilge out through a second vent on the ER (or any other opening on the ER)....

newer boats seem to have the bilge blowers set up to provide a negative pressure in the bilge to expel the fumes....the intake for the blower is a duct located with its opening in the lowest part of the bilge...the blower output is a duct attached to a vent on the ER that directs the fumes overboard....

cliff
 
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Tonka Boater said:
That seems odd to have the fresh air intake on the starboard side since that's the side that most boats fill from. There is a fuel tank vent on the forward starboard side but that's not a fresh air intake and has nothing to do with the blower or ventilating the engine compartment. Regardless, as was previously noted, even if the ventilation system sucks in fresh air it wouldn't be an issue since the intake would be up high and the gas fumes sit at the water level because they are heavier than air.

This whole discussion has me curious so I'm going to do some research.
Click to expand...
Tonka, I don’t know if most boats gas fill is on stbd side or not but on you’re 280DA and mine they aren‘t. My 280DA blowers exhaust out the port side a couple of feet from the gas tank fill/vent location.

On my 280DA with twins there are two blowers. Because gas fumes settle the pickup end is low near the bottom(oil pan) of each engine. They both exhaust out the port side. There are two hoses on the stbd side that direct the replacement air to the bottom of the engine room.

Eventually all air in the engine room would be changed but the location of the hoses would emphasis air flow low in the bilge through under the engines and out the other side, it’s the potential fumes that the system is after.

If another 280DA was on the other side of my fuel dock his blower exhaust and fumes from his fuel fill/vent fueling process would be about 5’ from my air intake. I think whether or not you should run the blowers during fueling is best answered with ‘it depends’.

I don’t flip power disconnects and only I run blowers after fueling, The only time I run them at slow speed is at the end of using it, prior to pulling into the slip and while I let engines run too cool down.
 
Here's the ABYC mandate:

2.6.5.2 External openings of intakes and exhausts shall be located and oriented to prevent entry of fuel vapors. In no instance shall the intakes and exhausts be closer than 15 inches (380mm) from the gasoline fill and tank vent fittings.

Assuming your boat's ventilation system is installed properly, there would be no risk in running the blower during fueling as long as the blower was started before the fueling began.
 
FWIW the Admiral and I took the boater's safety class a couple years ago.....when this subject of running the blower or not during refueling came up I drilled the instructor pretty good for a clarification because I was on the side that says it should be run......the official word from the instructor was that the rules call for blowers to be off during refueling and he was not going to entertain a discussion about possible reasons for it to be running....he said the official reason was because the blower could suck gas fumes into the bilge and possibly create an explosion hazard...I did not want to delay the class any longer and the Admiral was kicking me under the table so I let it go....so I guess if the marinas are following the rules they should insist on blowers being turned off during refueling....

cliff
 
In this litigious world we live in it's almost more important that we understand where liability would fall should something bad happen vs trying to be logical about the use case.

The worst case scenario (that I'm sure has played out somewhere in this country?) is a catastrophic event occurring during fueling where the owner of the vessel is found to have acted negligently by not following the manufacturers recommended procedures. Even if there was some failure in some system that was allegedly "ignition protected" I would assume the legal battle would be protracted and expensive. Kill a couple kids on the dock standing next to your $100k boat and it will be like lawyer chum in the water. Of course, if a marina gas attendant demands that you run the blower they would share liability in this case, I assume.

For the same reason I carry an umbrella policy (and hope to never need it) I do try to follow these kinds of suggestions when they appear in writing. No matter what folks on this board tell you the manufacturers recommendations will carry more weight.

Here's to safe boating and fueling! Maybe eventually Mr. Musk will give us an electric option so we can stop worrying about our bilge blowers.
 
I run mine while fueling, because my vents are on the side of the boat, and my fuel fill is in the back. Your individual configuration may vary.
Mine is SO LOUD, i only run before starting and while fueling. I also stick my head in and do a sniff test before turning on batteries.
 
Stee6043 said:
......Here's to safe boating and fueling! Maybe eventually Mr. Musk will give us an electric option so we can stop worrying about our bilge blowers.
Click to expand...

Or avoid the wait and get a diesel boat???
 
According to my studies for the my USCG License, you are to turn blowers off during fueling. Ignition of fuel in the tank during fueling is the greatest concern, so while your fuel cap is off and you are actively fueling, all electrical devices including blowers should be off. Once fueling is complete and gas caps are securely fastened, you are to start blowers and run long enough for one complete exchange of air from your engine compartment before starting engines.
Rob
 
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