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View Full Version : Venting ballast bags??



jmvotto
03-15-2011, 09:55 PM
I know this is a dumb question. But what is the reason to vent the rear bags from the top port hole ? Is is to burp the air in the bag or help them drain?

brain_rinse
03-15-2011, 09:59 PM
Both. It lets all the air escape when filling them up, plus it helps them drain more completely.

you da man
03-15-2011, 10:09 PM
Got mine vented with a hose and thru hull.

jmvotto
03-15-2011, 10:14 PM
Both. It lets all the air escape when filling them up, plus it helps them drain more completely.

Lots of people use a one way valve and tee to the drain line at the thru hull. If the drain line is full of water when the pump is emptying, how does this help drain?

Dont trailer so don't néed to burp bags much.

Ydm, I don't want more thru hulls especially looking at an ibs with two more drain pump..

brain_rinse
03-15-2011, 10:48 PM
Lots of people use a one way valve and tee to the drain line at the thru hull. If the drain line is full of water when the pump is emptying, how does this help drain?
That's how mine are hooked up. Not sure the physics behind it but it works great. Before the venting there would always be a few gallons that wouldn't drain, and now with the vents they suck down flat with very little water left.

mmandley
03-16-2011, 08:56 AM
Lots of people use a one way valve and tee to the drain line at the thru hull. If the drain line is full of water when the pump is emptying, how does this help drain?

Dont trailer so don't néed to burp bags much.

Ydm, I don't want more thru hulls especially looking at an ibs with two more drain pump..

I know i owe you pics bro lol. I just havnt been able to get my system back together my boat looks like a bomb went off but i should have it almost all together in a week.

IBS you only need 1 additional threw hull. You can use 2 pumps 1 on each leg, you Y them together and out the same threw hull.

Why vent your bags?

Well mainly this is because no matter what you do you can get air in the bags. 1st summer i didnt run vents as my Factory bags didnt have them, i also had 50 or so lb of water in my rear bags. and when i filled them this air stays in there as well as the Ski locker bag.

I got my 750s and they have vents so i used a Y and Ted them into the exiting drain right before the threw hull. This does 2 things.
1 it allows any air in the bags at any time to escape, and they will get air filling because of you pull the boat out of the water you drain the boat of the water from the inlet to the pump. Also a lot of the time when you go to fill the bags there is air in the manifold from the valve to the bags. So you never truly get your correct weight from the bags.
2 it allows the bags to drain when its full as an over flow. Yes the bag will over pressure your drain pump and drain if you don't have a vent but this allows the system to drain when full with very little extra pressure on the fill and drain pumps so the pumps are under less stress.

Ski locker bag unless you have some sort of check valve will almost always get air in it because the drain is on the curved section of the bow. So as you trailer the boat it tends to pick up air pressure and fill with air.

Lastly to your question of how does the drain line work if you have it Ted to the vent. 2 ways, 1 is the check valve is a 1 way line and when the pump is draining it cant use the vent. I don't use a check valve, and yes a little water drains down the vent but whats really happening is it creating a Vacuum based on the venturi concept and as the water passes the vent under pressure most of it skips over the Y joint and creates a vacuum and actually pulls any air out of the sac.
2 This also in turn allows the drain pumps to drain all the water because said vacuum is behind the water pulling air out so the heavier water will stay near the drain source.

jmvotto
03-16-2011, 10:58 AM
Mike, That last part makes sense without the one way valve. Using a Yvs. a T should help that. will a one way valve on the front bag with only two ports help it drain any better??

Holmes on Holmes taught me that air behind water makes it better for flow....


Could use use a plumbing mini vent on the third hole?, should be simple. I may give that a whirl.

NCSUmoomba
03-16-2011, 01:08 PM
Mike Holmes is my hero!

jmvotto
03-16-2011, 02:58 PM
Mike Holmes is my hero!

I wish i could get him to cross the border and fix my leaning cabin at the lake, i would do a show or two.....;)

snyderaaron
03-16-2011, 05:22 PM
what if you don't have a vent in your factory bags. Can you still vent them or would if be worth it.

squeeg333
03-16-2011, 05:23 PM
I'm trying to get this straight. Is the vent run off of the front capped port on the bags, and then t-ed into the drain line right before the thru hull?? Or is there a different way this is done? My brain isn't working today...

mmandley
03-16-2011, 09:04 PM
As for Venting, a T would work but your causing more turbulence then a Y but it does work as i have used a T when i didn't have a Y. < sounds like algebra >

snyderaaron - Can you vent the bags when there is no extra port? No you have to have a port on the top of the bag to vent. Its not a huge thing if you don't have vents but if you have the extra port you should vent it to get the most weight in the bag other wise it leaves air. If your not having an issue with air in the bags, and you don't have a 3rd port its really no big deal. Before when i ran the 400s i had no vent and i wasn't getting much air in them but at the same time they never drained all the way. Sometimes it wouldn't even drain i would get air lock and be stuck with 400lbs of water in my rear bag till i was able to get the air pushed threw the drain pump.


squeeg333 - On your bag you need 3 ports. 1 to drain, 1 to fill and 1 to vent. Other wise this doesn't work.

jmvotto
03-16-2011, 09:13 PM
Mike, thoughts on a mini vent threaded into the vent hole...

mmandley
03-16-2011, 09:15 PM
I think any kind of vent will work, its all about just giving the air someplace to exit. I don't think it needs to be the same size as the ports on the bag.

jmvotto
03-16-2011, 09:18 PM
Thanks I will give them a couple ideas... Dont like the idea of having extra hose onto of the bag if I don't have to...

If fly high was smart they would have put a diaphragm in the air release plugs... Problem solved

JesseC
03-16-2011, 09:51 PM
Here are a few pics of when I did this about 4-5 years ago. I just used a T fitting and a one way valve off of the evac line to the thru hull. I did this as an overflow/vent. Someone lef a switch on once and it cracked the evac pump, after adding the overflow/vent I have not had that problem since.

http://i132.photobucket.com/albums/q21/StarkRaven/ballast3.jpg
http://i132.photobucket.com/albums/q21/StarkRaven/ballast2.jpg

brain_rinse
03-16-2011, 09:57 PM
Not a great pic but shows how my rear bags are vented.

http://moomba.com/msgboard/attachment.php?attachmentid=4606&d=1268548662

jmvotto
03-16-2011, 10:22 PM
Thanks guys....;)

squeeg333
03-17-2011, 12:18 PM
That's perfect Brain. Thanks for that photo. That clears up my question. I've got the 750's (new for me this year), and wanted to vent them. I've got the 3rd port, so this will work well for me.

Thanks guys!

kaneboats
02-01-2012, 02:36 PM
I'm trying to get the stuff together for all my spring mods. I want to addd a vent line to my front/ski locker bag. I thought it didn't have a hole/plug in the front end but it does. It's not exactly on top but it is on the top side. I figure with the nose high it's high enough to let a heckuva lot of air out if I put a vent line on there. So, I guess I need a fitting. It should just be a W736 to screw into the bag in place of the cap. Then I can use a quick conncect with a barb and a piece of hose to a check valve, then a "Y" connector at the top of the drain line. Does that sound about right?

This is the fitting so if anyone has one in a box I'd love to have it. (I actually need 3 and will order them in a couple of days if no one has them lying around.)

http://www.wakemakers.com/fly-high-pro-x-series-fitting-w736.html

bergermaister
02-01-2012, 08:03 PM
Your description sounds exactly right on the setup. As for filling with it nose high to let the air out, I suppose that will work.

I have the fittings you need, 4 of them actually and 4 of the W742 quick disconnects too if you want them. Heck even the 3/4" T fitting and a bag of hose clamps. (T or Y - either should work). Had offered these up on the Christmas giving list but no takers.

PM me where you want them to go!

jmvotto
02-01-2012, 09:25 PM
Kane I have some extra 3/4 oem hose . I also have a couple flow rite quick connect male 3/4, not the fly high brand.They work fine for vents but not under pressure.

http://www.flow-rite.com/product/adapter-34-inch-male-npt-x-34-inch-hose

kaneboats
02-01-2012, 09:28 PM
Thanks, fellas. Sent a PM to each of you. I'll take care of you. Joe can vouch for me on that one.