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View Full Version : school me on ballast vent lines



sandm
04-28-2010, 12:46 PM
well, have upgraded the 2 rear bags, one's an 1100, and one's a 750 for now, but may go to the 1100 for consistency. they all come with 3 ports, unlike the factory gIII system that I have replaced. the dealer here(centurion,mc and nautique) stated that I need to have vents on these. they said that I can use the manual valves that are shipping with the new fly-hi bags or they recommended installing vent lines. I am understanding that there are 2 ways to do this and want to get the communities opinion on this one...

1-plumb a line from the 3rd port(vent) to the drain line dumping out the side of the boat and add a check valve from wakemakers inline to keep the water from flowing back through this as I drain the bag

2-plumb a line to a new port on the side of the boat next to the drain port.

I am open to either one, but want to know the pros and cons of each setup and how to vent the factory GIII bag that is in the center locker, as i can't replace it with anything larger due to having the walkthru..

thanks :)

stretch55
04-28-2010, 04:58 PM
Either way would work. If you tie into the existing through hull then you woul need a "Y" and a one way check valve to keep the water from flowing back down into the bag. If you just go off the bag into a knew through hull the you would just need to get a new through hull fitting. But keep in mind on the new through hull you put in there will be no one way check valve on it so will have the potential of taking on alot of "extra" air. Personally I would go with the "Y" and one way check valve. Good Luck!

sandm
04-28-2010, 05:09 PM
how would it take on extra air if the pump is pushing water into the bag, it would seem that the water would force the air out the vent? I would think the natural flow would be for the bag to push air out the vent prior to "expanding" as it gets larger, and since it drains out the bottom, gravity would pull the top of the bag down and force any air within it out as you drained it?

brain_rinse
04-28-2010, 05:25 PM
Either will work just fine. I used a wye fitting and check valve (option 1) because I didn't want to add 4 new holes in my boat. Option 2 may lead to the bag filling while trailering, but as you said it doesn't matter... it will all get pushed out as the bag fills with water.

I vented my ski locker bag the same as the others... it just required a longer hose.

sandm
04-28-2010, 05:31 PM
thanks..

guess it's time to start putting together pricing and figuring out which way would work better. "y" in the existing line is easier, but the separate vent might be less problematic if the check valve broke or quit working on the lake..

brain_rinse
04-28-2010, 05:35 PM
The check valves are pretty slick. They are just 3 overlapping rubber triangles that allow one way flow. Of course anything can fail, but I wouldn't worry much about that. Worst case it takes longer to drain because some water is leaking back into the bag thru the vent. I wouldn't make this a deciding factor I guess. Either way I think you'll be happy with the improvement!

mmandley
04-28-2010, 06:27 PM
I just got my 750s plumbed in and this is all it took to vent the bag.

Run a line from the back port of the bag < vent > then run this and Y it into the main drain up at the threw hull. No check valve is needed at this point.

Heres why, the pump is pushing the water so fast it actually creates a vacuum over the vent and doesn't allow water to back flow into the bag.

Why do you need to vent the bag in the first place? Because air always gets into the system. Its a fact of life here. It doesn't matter if you turn on the pump, see water and plug it to the bag, it will still get air in it. I don't know how but it does. The Vent allows 100% of the bag to get water. When the bag is full not only will the water then pass threw the drain line out the threw hull like an unvented bag it will also push out the vent and tell you its full as well.

Sunday we ran the 750 full and it over flowed like expected threw the vent line as this is now the path of least resistance in the system. We surfed and the bag stayed completely full.

When we hit drain it actually drained the entire bag, no 40 lbs of water left in the sac like we had with the 400 last summer. I was so impressed and happy.

JesseC
04-28-2010, 09:00 PM
I used a T fitting to connect into the drain line. I did this about 3 years ago when someone accidently kicked the fill switch and when the bag filled as much as it would go the weak point ended up being the drain pump and it cracked and filled the bilge with 500 lbs of water. Great test for the bilge pump. So I added the vent/overflow to make sure that would never happen again. I have not had any issues with the whale valves and loss of function, also the bags drain completly. Here is how I did mine:

http://i132.photobucket.com/albums/q21/StarkRaven/11aStarboardbag.jpg

mnpracing
05-24-2010, 10:59 PM
Where can you buy check valves. I have the GIII system so I think they are 3/4" hoses. I see 1" on wakemaker's site, and I'm hoping to find something that will do the trick a bit cheaper.

mmandley
05-25-2010, 12:33 PM
I want to say i was told you have to goto the Plumbing type stores. The Home Depots don't carry the smaller sizes. These are a bit pricey thought at 20 a pop.

JesseC
05-26-2010, 06:25 PM
Where can you buy check valves. I have the GIII system so I think they are 3/4" hoses. I see 1" on wakemaker's site, and I'm hoping to find something that will do the trick a bit cheaper.

Here is the ones that I went with. The local home improvement stores will not have ones like these with the rubber diaphrams. They just have the swing or high pressure style. I think I got mine at West Marine, but they do not show up on their website. Here is a link of you have a Boaters World near you.

http://www.boatersworld.com/product/MP80821143.htm



.

mnpracing
05-26-2010, 08:11 PM
How does the vent line help the bag drain completely? I was thinking it was because it would let air in to replace the water leaving the bag, just like pouring gas out of a vented gas can. But since the vent line shares the drain line how does it help drain the bag? Also, with a check valve, this would prevent water and air from entering the bag.

JesseC
05-27-2010, 12:17 PM
How does the vent line help the bag drain completely? I was thinking it was because it would let air in to replace the water leaving the bag, just like pouring gas out of a vented gas can. But since the vent line shares the drain line how does it help drain the bag? Also, with a check valve, this would prevent water and air from entering the bag.

You are right about water and air not entering the bag. If you look at the pic I posted on the first page, you can see that my bag gets sucked completly flat. Air does not come in and the bag just turns into a big wafer. The vent line is more for air to get out from trailering/air in the lines things like that. I put mine in to act more as an overflow. The vent was just an added plus. If the bag overfills, the water just goes out the port. The first time I overfilled without the vent/overflow I cracked one of my evac pumps and all the water went in the bilge. The check valve was to make sure water didn't re-enter the bag when draining. Some setups don't have this problem, but due to my setup and angles water was going back in the valve. My pump must not be as fast as the others.

mnpracing
05-28-2010, 09:16 AM
JesseC - In the picture that you posted, where is your drain line on the bag? Is the T tapped into the drain line for the bag in the picture? Thanks for your help.

JesseC
05-28-2010, 09:50 AM
JesseC - In the picture that you posted, where is your drain line on the bag? Is the T tapped into the drain line for the bag in the picture? Thanks for your help.

The T is tapped into the drain line, you are correct. Mine drains off of the back/bottom of the bag and I just tapped that line and used a 1 way valve.