How well does your blower work?

[a70eliminator]

Hi everyone, I did a search and found all the info I needed, but what the heck it seems like a good topic for discussion anyhow. I'm looking to improve on the system if anything at least maybe I'll remember to turn it on next time.

 

[QC]

Re: How well does your blower work?

What are you trying to improve? Faster air exchange?

 

[wire2]

Re: How well does your blower work?

If the plastic duct has corrugation on the inside, the flow is greatly reduced from using smooth inside. Corrugated outside is ok.

 

[thrasher]

Re: How well does your blower work?

Mine makes plenty of noise, but I have no idea how well it actually works, I usually leave the engine cover open for 5 minutes prior to starting the engine as I figured that was more effective than the blower.. It also gives me a chance to check for any water leaks (just part of my pre-check) before loading people and coolers into the boat.

Gary

 

[WaterWitch2]

Re: How well does your blower work?

If it isn't working well enough then you wouldn't be asking. (BOOM)

 

[Chris1956]

Re: How well does your blower work?

Gary, You really need to run the blower. Gasoline vapors are heavier than air and settle into the bilge. Opening the engine cover may or may not draw them out, especially if it is not windy. The blower hose originates in the bilge and is designed to suck out the lowest level atmosphere.

BTW - Always give the air exhaust athe sniff test when the blower is running, prior to starting 'em up. if you smell gas, don't start it. If you smell fish, but no gas, it should be OK to start.

 

[QC]

Re: How well does your blower work?

I have a blower question to ponder. Why do you need to plumb anything on the passive side? My boat has two hoses, one from the bilge to the blower. That one makes sense. Then there is another one that goes from the other vent to the bilge. I don't get this one. No matter what, the negative pressure from the blower can only be replaced by air from elsewhere right? Seems like the "passive" hose limits the vent's ability to get air to the intake and has no positive impact on blower efficiency.

 

[Dakota47]

Re: How well does your blower work?

it blows.

 

[thrasher]

Re: How well does your blower work?

Thanks Chris,

As mentioned I do always look around the engine to check for water and oil leaks and just check everything prior to starting the engine. I would certainly notice any fuel vapour smell whilst checking the sump of the engine and would not start the engine. I will take your recomendation to heart and run the blower whilst I do my pre-check, but the thing is quite noisy (with the engine cover open) so I haven't used it in the past!! Another item to go on the pre-check checklist (plus ear plugs!!).

Gary

 

[a70eliminator]

Re: How well does your blower work?

I have a blower question to ponder. Why do you need to plumb anything on the passive side? My boat has two hoses, one from the bilge to the blower. That one makes sense. Then there is another one that goes from the other vent to the bilge. I don't get this one. No matter what, the negative pressure from the blower can only be replaced by air from elsewhere right? Seems like the "passive" hose limits the vent's ability to get air to the intake and has no positive impact on blower efficiency.

Well your right about the negative pressure, but having fresh available would greatly improve airflow to get the stale stuff out of there, also when underway with the fan off it's just a restriction in the hose, therfore the other vent hose provides ventalation, I think?

 

[a70eliminator]

Re: How well does your blower work?

Hi everyone, I did a search and found all the info I needed, but what the heck it seems like a good topic for discussion anyhow. I'm looking to improve on the system if anything at least maybe I'll remember to turn it on next time.

Actually mine works well, good airflow out the rear vent, and intake will hold a piece of paper to it, then the passive hose that just leads to the side scoops to ventalate while underway with the fan off, the improvement I would like is some type of lockout that interupts ignition if the fan isn't on, I sometimes forget to run it and it just makes me nervous to leave it on all the time. It would have to be a holding relay of some sort so once the engine is initionally started the fan could then be turnrd off without killing the engine.

 

[QC]

Re: How well does your blower work?

Well your right about the negative pressure, but having fresh available would greatly improve airflow to get the stale stuff out of there

Well if there is no hose on the vent, it gets fresh in with absolutely no restriction. Again, if the blower blows out, fresh air has to come in . . .

also when underway with the fan off it's just a restriction in the hose, therfore the other vent hose provides ventalation, I think?

Same deal, no hose on non-blower side = more air . . . for the engine and/or the bilge, at least I think so

 

[Scaaty]

Re: How well does your blower work?

I have a blower question to ponder. Why do you need to plumb anything on the passive side? My boat has two hoses, one from the bilge to the blower. That one makes sense. Then there is another one that goes from the other vent to the bilge. I don't get this one. No matter what, the negative pressure from the blower can only be replaced by air from elsewhere right? Seems like the "passive" hose limits the vent's ability to get air to the intake and has no positive impact on blower efficiency.

My IO has 4 inlets/outlets..2 a side..2 vented inward, hoses to the bilge..2 outlets, hoses bilge too, one (blower) to clear bilge fumes if any (I ALAWAYS do a sniff/ feel-up test)..other for the evac thing

 

[QC]

Re: How well does your blower work?

Mine is the same Scaaty. Two with no hoses, louvered like side vents, one port, one starboard. Additionally there is another one that has the hose from the bilge thru the blower and out, and one that I am calling "passive" has a hose into the bilge. I submit that one, does not need, and safety does not benefit from, the hose . . . When the blower is blowing, fresh air would find it's way from all three of those vents down into the bilge and out the blower hose. As it is plumbed now, the blower hose supposedly gets its air from the hose that is opposite and in the bilge. That to me seems kinda stupid. The blower cannot say "hey you hose over there, I want my air from you, so don't you let those other vents get involved." Actually, if you believe in the path of least resistance, then air bypasses that hose and comes around it from the other, less restrictive, vents . . .

 

[Boatist]

Re: How well does your blower work?

Best setup is two hoses on each side. On the side with the blower one hose goes to the blower then out the cowl. The other hose is the same but with no blower. Both hoses on this side should go as deep in the bilge below the engine as possible but not so deep that could be blocked by bilge water.

With no wind or boat movement the bilge blower still sucks air out. With wind and boat movement the hose with no blower move more air out than the one with the blower.

The idea is to move fumes out before they get high enough in the bilge to reach an ingition sourse, the engine.

The two air inputs on the other side should come into the engine compartment as high as possible. If possible higher than the flame arester. The idea here is to bring air in high and help move gas fumes down and out the exhaust hoses.

 

[Scaaty]

Re: How well does your blower work?

Mine is the same Scaaty. Two with no hoses, louvered like side vents, one port, one starboard. Additionally there is another one that has the hose from the bilge thru the blower and out,
and one that I am calling "passive" has a hose into the bilge.
I submit that one, does not need, and safety does not benefit from, the hose . . . When the blower is blowing, fresh air would find it's way from all three of those vents down into the bilge and out the blower hose. As it is plumbed now, the blower hose supposedly gets its air from the hose that is opposite and in the bilge. That to me seems kinda stupid. The blower cannot say "hey you hose over there, I want my air from you, so don't you let those other vents get involved." Actually, if you believe in the path of least resistance, then air bypasses that hose and comes around it from the other, less restrictive, vents . . .

OK, I think I see what ya mean here. I would think that the passive needs to be low in the bilge for venting at speed (mine is of the lowest fumes (where the gas fumes lurk, IF there are any..which should be none of course). But I can't remember just how close the are to each other, or the hight. Next time I crawl back there I will have a lookThink Boatist has it covered, but of course it does depend on the individual boat too...(thats why I like my OB..this Sterndrive of mine is a PITA)

 

[tommays]

Re: How well does your blower work?

"[FONT=Verdana,Arial,Helvetica,sans-serif]The lower flammable limit or lower explosive limit (LFL or LEL) of gasoline is 1.4 percent; the upper flammable limit or upper explosive limit (UFL or UEL) is 7.6 percent. This means that gasoline can be ignited when it is in the air at levels between 1.4 and 7.6 percent. A concentration of gasoline vapour in air below 1.4 percent is too "lean" to burn. Gasoline vapour levels above 7.6 percent are too "rich" to burn. Flammable limits, like flashpoints however, are intended as guides not as fine lines between safe and unsafe."



A few facts about how little it takes



Tommays
[/FONT]

 

[45Auto]

Re: How well does your blower work?

Hey QC,

Only reason I could think of to have a hose on your "passive" vent is if the vent is located in a low pressure area when the boat is moving. In that case it would suck fumes out of the bilge when the boat is moving, same way that rolling a window down in a car a half inch or so will pull cigarette smoke out.

Other than that the hose would just be restriction (probably not much of one though at the velocities its seeing) to your blower input.

 

[PhatboyC]

Re: How well does your blower work?

I always wondered the efficiency of the passive vents while under way. Anyone ever stick a thermostat under there to see the temperature difference? Hotter air diminishes engine's performance.

 

[amynbill]

Re: How well does your blower work?

I love my wife.