blowers and vents

[chris2114]

OK well while going through everything I found that my blower vet tube is ripped.so I'm going to order anew one, but was wondering there are two vents on this boat its a 1995 rinker 180 I was thinking of installing dual blowers and having new unplugged and use it as a back up in case the primary stops working. I could do that or use the blower in reverse and suck fresh air in one side and blow fumes out the other.
I kind of just want everyone's opinion has any one use the blowers this way before is it safe to do so, can't see why not.
And this is my first inboard when should I use the blowers, I know obviously after fueling and before start up but I have heard of people saying they keep them on while running is this really necessary
Thanks for the help

 

[Grub54891]

A boat that size shouldn't need dual blowers. The blower will exhaust any fumes while fueling,or before startup. Keep it on while idiling,or going for a sliw no-wake cruise. Once the boat is moving along,the blower can be shut down,the vents are designed to "grab" the air and vent while underway.
I should add,that anytime before starting for the day,open the lid,inspect for leaks,check the oil,ps,coolant if ya got that systym.
One boat I worked on had a gizmo,that would automaticly turn on the blower when the key was turned on,then shut down at a preset rpm. I gotta get one of them,makes it easy to not forget to turn em on.
And welcome to I-boats!

 

[dozerII]

I recommend using Heavy Duty 3" RV sewer hose for your blower ducts, it is really strong and similar in price to the marine ducting you can buy.

 

[shrew]

Sucking air in wouldn't make any sense. It's not a sealed compartment. The blower fans will vary from 100 - 250 CFM. An equal amount of air is already being drawn in to replace the air being vented out. You will more than likely only slightly increase the volume of air displacement over time, but not enough to justify an inbound fan. Dual out fans are overkill due to the size of the space and the volume of air CFM from a single fan. About the only thing that would make sense would be a 2nd fan on a 2nd switch as a parallel redundant blower. That would be overkill IMHO, but would make more sense than either doubling the blower capacity or adding an inbound vent. (Just one man's opinion)

 

[alldodge]

OK well while going through everything I found that my blower vet tube is ripped.so I'm going to order anew one, but was wondering there are two vents on this boat its a 1995 rinker 180 I was thinking of installing dual blowers and having new unplugged and use it as a back up in case the primary stops working. I could do that or use the blower in reverse and suck fresh air in one side and blow fumes out the other.
I kind of just want everyone's opinion has any one use the blowers this way before is it safe to do so, can't see why not.
And this is my first inboard when should I use the blowers, I know obviously after fueling and before start up but I have heard of people saying they keep them on while running is this really necessary
Thanks for the help

Don't see any reason for a second blower. Unless your boat is real loud you can hear it when it's running. It will make some kind of different sound if it starts to go out. Even if it did just stop you would notice and then open the hatch and let it air out so you can start and make it back home to replace. Haven't heard of many going out, and those in most cases was salt water area and a lot of time

 

[bobdec]

I agree 1 blower sucking air out in an 18 footer is enough. Purpose of blower is to suck heavy fuel fumes out of lower portion of bilge/engine compartment and disperse them overboard. IMO adding a second blower, blowing fresh air in, will not help acomplish this. Depending where you place the fresh air input hose ,it could disperse the fuel fumes throughout the bilge/engine compartment. This would actually slow down the clearing of fumes by the origional low placed (vacuum out) blower hose. And depending on design may actually push the fumes elsewhere in the boat. You bassically want a slight vacuum in the engine compartment when the blower is on. Under way the engine intake acts like a large vacuum cleaner and sucks all fumes into the intake, and fresh air enters via the vents.

 

[Chris1956]

As was said, one vent allows air into the bilge. It should have a hose long enough to reach the bilge. The other vent allows air to leave the boat. It should have a blower in a piece of hose connected to the duct. The idea is that the blower creates a vacuum in the bilge, pulling fresh air into the bilge, and exhausting any gas fume-laden air. You can turn the "exhaust" vent around, and as the boat moves, it will passively draw air out.

Make sure you use only marine-grade blowers. Other blowers can spark, potentially causing a fire or explosion. Wouldn't that be ironic, when the device designed to reduce the risk of fire or explosion, actually causes it?

 

[Thalasso]

A boat that size shouldn't need dual blowers. The blower will exhaust any fumes while fueling,or before startup.


Should never be on while fueling

 

[chris2114]

OK thanks, so the other vent does not have any kind of hose directing it to the engine compartment its just a vent. I would need to have a hose that directs it to the engine compartment while underway but no blower and just replace the current blower hose.

 

[Grub54891]

A boat that size shouldn't need dual blowers. The blower will exhaust any fumes while fueling,or before startup.

Yup,thanks for correcting that. After done fueling it should have read.

Should never be on while fueling

 

[muskyfins]

Also the typical set up for a "blower" has the engine compartment in a negative pressure condition. Any fume, vapor or aerosol inside the compartment or hull cavity will be drawn into the fan unit and fresh air will be drawn from anywhere there is an air leak. (opposite vent, cracks around engine hatch, etc) If you use a second unit on the opposite vent, the cavity could and likely would turn positive. This will create turbulent air within the engine compartment and while some fumes will escape via the suction fan or leak paths, much of that air will be the same new fresh air you just brought in.

 

[smokeonthewater]

NO you do NOT need or want a hose directing an INTAKE vent into the engine compartment..... IF it HAS a hose from the factory running to the bilge it is a passive EXHAUST vent... IF it is an intake the air will be drawn to the engine without any hose needed.... an intake hose is ONLY used where intake air must pass in and out of a sealed compartment that is not exposed to the engine room.

 

[Chris1956]

Upon further review, you will want a hose on the exhaust vent, with the other end under the oil pan. This hose will suck out any gasoline fumes. Remember gasoline fumes will settle into the lowest part of the bilge, since they are heavier than air. When they are sucked out, fresh air will replace them.

 

[ken51k]

smokeonthewater is dead on, you do not want a hose on the intake. A intake hose will cause the fresh air coming into the bilge to mix with any gas fumes and spread them out more. You just want the fresh air to replace what is being sucked out from the lowest part of the bilge. Gas fumes are heavy so they will settle to the bottom, force air in and you'll mix up the heavier fumes and spread them out more

 

[NYBo]

You should never, ever have a blower blowing air into the engine compartment! That would pressurize the compartment, causing fumes to escape from any and all air leaks, which can fill the rest of the bilge, the cabin, etc. :target:

 

[redneck joe]

A boat that size shouldn't need dual blowers. The blower will exhaust any fumes while fueling,or before startup.


Should never be on while fueling

Always heard that. Why?

 

[Grub54891]

You shoul have everthing shut off while fueling up. Any static caused by the blower running,or ignition on to listen to the radio,lights ext,could cause a spark and ignite the fumes. The same goes for your car,shut it off to be as safe as possible.

 

[Thalasso]

You shoul have everthing shut off while fueling up. Any static caused by the blower running,or ignition on to listen to the radio,lights ext,could cause a spark and ignite the fumes. The same goes for your car,shut it off to be as safe as possible.

That is not why.
While fueling and if you have your blower on, all the blower will do is suck fumes into the compartment.