I/O Bilge Air Duct Venting

[hockey4chr]

Hello still kinda new to this website. So if this is not in the right spot please let me know or move if you can. Thank you.

Anyways, I am trying to figure out the Air Duct Hose Routing on my 1976 26' Reinell Cabin Cruiser. I have tried to do some research but have not found any one way to do it just yet. Please see the attached PDF drawing of how it is set up and let me know what you suggest please.

I have a Intake on the Port Side and a Exhaust on the Starboard side. I found on a little training video on bilge exaust that stated that if you have a motor hooked up to one port and just a natural line on the other that you might have a issue with the motor air coming back into the natural air. This would totally defet the purpose of exhausting the air out with the motor.

Any tips will help. Thanks.

 

[haulnazz15]

Re: I/O Bilge Air Duct Venting

Okay, the easiest way to look at it is: The side where the vent scoops are facing "forward" is your intake side and should have a hose connected to one or both of the holes leading to the bottom of the bilge. The opposite side which has the vents/scoops exiting to the rear is where the blower motor should be attached, as well as a hose also going down to the bottom of the bilge. The intake air "scoops in" fresh air while underway, and the blower "blows out" the exhausted air out the back.

Just make sure your intake is on the side that would scoop up air when moving forward and you're fine.

 

[hockey4chr]

Re: I/O Bilge Air Duct Venting

Haulnazz15. Please bare with me as i something have a hard time explaining what im trying to say.

I 100% understand what you are saying but what issues i had was when the Video i watched said that on the Exhaust side when you have 2 ports in the same exhaust outlet box (thingy) like mine. So lets say you have the motor hooked up to One side and the Natural air just sitting almost at the bottom of the Bilge (still on the exhaust side) then when you turn on the exhaust blower it will pump the air from the bilge into the exhaust outlet box (thingy) but because there is nothing preventing the air going in the other port in the same box is just pushes the bad air back in to the bilge.

I hope i explained it better. Please see the green line on my drawing where it shows just the air circulating in the box and not making its way out of the exhaust box (thingy).

Thank you.

 

[Bondo]

Re: I/O Bilge Air Duct Venting

Ayuh,.... If ya have 2 vent lines goin' to the same louvered vent box, the line from near the bottom of the bilge oughta have the blower suckin' out that 1,...
Gas fumes sink,...

The vent box is vented, air, like water 'n electricity take the path of least resistance, which is outa the box, not back down a tight tube,...

 

[haulnazz15]

Re: I/O Bilge Air Duct Venting

The vent box is vented, air, like water 'n electricity take the path of least resistance, which is outa the box, not back down a tight tube,...

Agreed. The air will exhaust out of the vent box, even if there is a second tube connected to it. I'd put the blower motor on the hose outlet furthest aft just the same.

 

[hockey4chr]

Re: I/O Bilge Air Duct Venting

Bond-o
Thank you that totally makes sense. I work in a Pneumatic Company and should of thought of that.

Now to add to the question... would anyone recommend a motor being on the Intake side? that louvered box has two vents as well. Just wondering.

 

[hockey4chr]

Re: I/O Bilge Air Duct Venting

Thanks for the reply. I will do that.

 

[spdracr39]

Re: I/O Bilge Air Duct Venting

I have been told you do not want a blower pushing air in because if you pressurize the engine bay the engine air could be pushed into the cabin.

 

[haulnazz15]

Re: I/O Bilge Air Duct Venting

No need for the extra blower. One blower should be more than adequate to exhaust any errant fuel vapors from the bilge in short order.

 

[Bondo]

Re: I/O Bilge Air Duct Venting

No need for the extra blower. One blower should be more than adequate to exhaust any errant fuel vapors from the bilge in short order.

Ayuh,.... 'n there's natural air flow when underway,...

 

[hockey4chr]

Re: I/O Bilge Air Duct Venting

Ayuh,.... 'n there's natural air flow when underway,...

No need for the extra blower. One blower should be more than adequate to exhaust any errant fuel vapors from the bilge in short order.

Yes thank you that makes complete sense as well. Thanks for the help everyone. I love this site... Very knowledgeable people.

 

[hockey4chr]

Re: I/O Bilge Air Duct Venting

I have been told you do not want a blower pushing air in because if you pressurize the engine bay the engine air could be pushed into the cabin.

Thanks for the info. I did not think about that till you said it. all though you are getting more "cleaner" air in it adds fuel to the fires sense fire likes oxygen.

 

[UncleWillie]

Re: I/O Bilge Air Duct Venting

There are Federal Requirements on how much air the Blowers need to move based on the size of the engine compartment.

Your boat may need 2 blowers to meet the standard.
Is there any indication (Witness Marks) that there used to be a second Blower?

Otherwise add a second blower or block off the other Port to prevent Back-flow into the boat.

 

[hockey4chr]

Re: I/O Bilge Air Duct Venting

There are Federal Requirements on how much air the Blowers need to move based on the size of the engine compartment.

Your boat may need 2 blowers to meet the standard.
Is there any indication (Witness Marks) that there used to be a second Blower?

Otherwise add a second blower or block off the other Port to prevent Back-flow into the boat.

Thanks for the internet page. I will measure my space and see what type of blower output i have.

And about the indication of another blower in there is kinda a trick question....

So the person that owned it before me i had to redo all the wire because they would just put splice after splice in the line and never fix it correctly.

With that being said there was Two blowers in the setup. One just dangling there on the "Intake side" and the other Exhaust side had the exhaust hoses hooked up to both sides of the blower so it was just bringing in the outside air and spitting it right back out through the same motor. Never exhausting any of the bilge air.

I'm going through the boat with a fine tooth comb and finding things like this just crack me up. been restoring all the functions on this boat for about 6-9 months.

But being i know only so much that's why i reached out for help from knowledgeable people on here.