Need bilge blower advice

walleye

Because of conversations on this site I've learned of the importance of blowers (and not just running them prior to starting). My problem is mine are in need of some repair and TLC and I'm not sure of the best way to go about this. Honestly I'm a little confused as to the routing of the current setup as it doesn't seem adequate. As you'll see in the attached pics, there are two vent lines dropping down from inside the stern storage hatch to roughly the top of the engines. No blower motor attached to these; what is their purpose? The last two pics show the actual blowers (I see I need to reattach the line to the one blower). Should these lines be longer and placed under the engines to get to the lowest point in the bilge? As is they are a good foot or more from the bottom of the bilge. Thanks in advance for advice and info!

Michael T

First my guess is that the "vent" hoses you see at the aft of your engine bay are fresh air supply hoses for the engines and engine bay. Fresh air from side vents and aft vents helps the engines and the blowers by preventing a semi-vacuum. So that part appears normal to me.

As for the actual blower vent hoses, yes, you are correct they need to be in good repair and attached. Should be easy to do.

I don't think they need to be under the engines. I have owned two Rinker cruisers a 2013 EC 310 and a 2014 EC 360 and both had blower vent hoses approximately where yours are...except they were attached....LOL  :-)

Black_Diamond

So those two hoses from the hatch bring in fresh air. Ideally they are relatively close to the bilge where they end. The goal is to get air moving at the low spots, as that is where fumes would gather. So you want a path of fresh air into low areas and the blowers to vacuum from those areas as well. Hope that makes sense. If you replace the vent tube, it is not dryer duct hose, there is marine rated vent tube. Those tubes get brittle over time, seems every 4 years I replace mine b

Black_Diamond

Here is how low my vents from
the hatch go. 

walleye

Thanks MT and BD. Appreciate the quick responses. Only additional question is re: the fresh air vents. Why are they run into the storage hatch? Can't imagine there's much fresh air circulating throug there. Or is the idea that the two side blowers (once repaired!) are sucking air/fumes out the side and in doing so creating a vacuum that is pulling whatever fresh air there is from the locker?

Michael T

Yes the engines and blowers will pull a LOT of air in there. It would probably suck a squirrel in if it were outside LOL.

LaRea

Is there an easy way to test the blower system with visible smoke to see exactly how well it's working?

The smoke would have to be heavier than air.  Otherwise, you could use the spray-can smoke used to test smoke detectors.  You could cool the smoke with dry ice, like with a stage fog machine, but that's a PITA and might not work.

Suggestions?

Michael T

If you really wanted to test the efficacy of your blowers you could put some colored smoke at the fresh air intakes and put on the blowers. that would show the circulation.

But IMO that is not necessary. If you can hear the very distinctive noise of your blowers as they wind-up that IMO shows that they are pulling. Put your hand at a vent or hose intake. You should feel the air flow.

If your hoses (marine not home plastics for fire retardation) are all connected another check mark.

IMO opinion the location of your hoses is fine. 

I have never had a Rinker (and I've had 9 with two cruisers) where they went under the engines.

My guess is that is because there are three distinct compartments under the engines. One under each engine and one in the stringers between the engines.

So if I were going to extend (and I wouldn't) the hoses under the two engines then I'd run a third hose between the two internal stringers or you could have a compartment with fumes trapped in it.

But, IMO, that's not necessary for a normal application. If your blowers are pulling normally - put your hand in front to see if you feel the air, your hoses are marine and connected, your hoses extend to the floor - as per the picture you have shown - you will be fine. I'd be careful modifying something that Rinker (hopefully) had thought out and used for many years.

MarkB

@Black_Diamond is that the intake duct and the exhaust duct side by side?  If so, those should be seperated by many feet.  If they are both intake and exhaust, the risk with that setup is the blower just sucks in air from the intake duct and short circuits the entire engine bilge. So you really don't end up ventilating the engine compartment, you just pull air from outside and exhaust it right out.

If you have 2 exhaust lines then that probably makes sense.

As Al indicates, the exhaust should be at the lower point to exhaust accumulated gas fumes. 

The intake duct should come in as far from the exhaust as possible. The surveyor who reviewed my new boat before purchase, I believe said they should be separeated at least 36" appart.  To be honest, I can't see why an intake duct is needed anyhow. The most important thing is if you exhaust from the low point, the air will convey from the vent on the side of the boat, down to that point and turnover the atmosphere in the engine bay.

Black_Diamond

Those 2 hoses in my pic are both fresh air intakes. I had zero hoses on any of the 4 fresh air intakes when I bought the boat new. So I added all of the fresh air ones and redid the exhaust ones as they just layed next to my starboard engine. 

walleye

Thanks all, much appreciated and helpful feedback. Could a guy throw some dry ice and water into the bilge if he wanted to see blower effectiveness? From what I recall, dry ice "smoke" is heavy and sinks to the floor. 

walleye

Both of those vertical hoses you see in my first pic are intake vens from the storage hatch above. The exhaust lines are those on the side of each engine. I inspected further today and there doesn't appear any good way I could route exhaust lines any lower into the bilge than they currently are without smashing them somewhat (due to tight spaces between engine and manifolds and the transom). I assume I don't want to restrict their air flow by reducing their size via jamming/smashing them through a tight spot? I feel better knowing that MT thinks the current layout is ok as that's what his boats had as well. Thoughts?

LaRea

@walleye - great idea to throw dry ice into the bilge water.  If the blowers don't evacuate that vapor, they aren't doing their job.

Black_Diamond

I would do it in a bucket. The thermal shock could very well damage the fiberglass.