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Vent or not


moto96s

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I have two 750 fat sacks each fed by a jabsco ballast puppy. I have not vented the bags yet as I hate drilling holes in my boat.

I have read a couple of threads in which people have stated they have never vented their bags. I would assume that is OK using a tsnunami or aerator style pump as they might not be able to develope enough pressure to rupture the bags. I would also assume that my ballast puppy pumps could develope enough to burst the bags(ohhhhhhh, what a drag). My question is has anyone actually witnessed one of these bags breaking for this reason. I know no matter how careful I am one day I will forget, or someone will lean on the switch, or, you get the idea. I do like being able to really fill them up completely, and suck them dry and flat with no vent, but do not want to risk the inevitable.

So, anybody actually have one pop!

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Why not do it right? It's not a big deal to vent. You will know when they are full by simply seeing/hearing the water flow out the vent hole.

I actually HAVE done damage by not venting when I first installed my ski locker sack (had the vent, just didn't have the time to install it). Daughter distracted me, it ran too long and started pushing out the mounting ring to the ski locker door. Luckily I was able to fix it without much issue but could have been worse had I not noticed it. I could see it doing other damage as well to the boat if unvented.

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No, I did not know! I have some check valves I could use to help with sucking them dry on a pump out, but how do you vent without drilling?

Out from under the back of the motor where the motor compartment vents are? I have been thinking about trying to go out that way.

And can I still really fill the bags all the way?

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Yes, I tied my vent lines in with a Y barb as shawndoggy notes, and also put a check valve between the sac and the Y so the pump can suck the bag flat. Works great.

  • Like 1
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There are no existing vents. Sorry if I was not clear.

Guess I will just have to bite the bullet and drill away.

May try to bring all vents toward the bow to help eliminate the dreaded siphon effect or do the vent left to right, right to left routine.

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I really regret venting and I am likely going to plug my vents. My sacks open my rear hatches before they get full and I am always messing with them while they fill. I am probably going to piggy back the rear sacks so when the finish filling they "vent" into secondary sacks further forward in my boat. Even with those "vents" I will need to be careful as ii worry about pressure on the fiberglass. But I will see the rear hatch and seats raise hopefully before there is a problem. There seems to be no getting around monitoring your sacks while they fill.

Sent from my SGH-T889 using Tapatalk

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Could he wye into the bilge pump vent? I ask because I'm considering doing the same with just my starboard sac since it fills the fastest out of the two rears to see how I like venting without drilling any holes yet. Would he (I) then have to put a check valve on the bilge line to make sure you're not pumping water into the boat once the bag fills? And what about draining while surfing? Do you have to cross-vent?

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just wye into your existing vents:

http://www.wakemakers.com/hose-barb-wye.html

^^^ this is exactly right. Its how mine are done.... remember gravity is your friend..... so Y in to you existing vent on the downhill gravity side RIGHT before is goes thru hull. You may need to take a zip tie and pull some slack up in the hose so you have 6-8" of downhill length to Y in to up in the gunnels before it hits your OEM thru hull.

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I have no existing vents. This boat had no ballast system at all when I bought it. I installed the two ballast puppies and the two 750s in the rear lockers. The only through hull above the water line I know of is the discharge for the bilge pump. I do not want to tie into it as I want to leave that as a dedicated fitting/line. Does not make sense to me to tie into that.

I just need to go ahead and install a thru hull, for the vent lines. No reason I can't do two vent lines into one vent thru hull with check valves installed that I can think of.

However, if I do one on each side, I can tell which side is full first by which side of boat water is coming out of(opposite if I cross lines to eliminate siphon).

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I wouldn't worry about venting. I never have on any of my systems and never had an issue.

Edited by old skool malibu
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I really regret venting and I am likely going to plug my vents. My sacks open my rear hatches before they get full and I am always messing with them while they fill. There seems to be no getting around monitoring your sacks while they fill.

I don't monitor mine - I turn the switch to off when I hear water coming out of the vent.

I wound worry about venting. I never have on any of my systems and never had an issue.

But are you using a piggy back setup off of the week aerator pumps or using an impeller pump. You CAN cause damage with an impeller pump...they are no joke.
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I added a 750 bag and johnson pump in each of the locker on our vlx. If I were to get a fitting for the top of the bag and run a hose to the existing ballast line using a Y would this be sufficient to vent/drain the bag if I were to accidentally leave the pumps running?

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yes

Would it be beneficial to add a check valve in the mix or would this not be necessary? I have the bags sharing a fill at the Thru hull under the engine.

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  • 5 weeks later...
I don't monitor mine - I turn the switch to off when I hear water coming out of the vent.

But are you using a piggy back setup off of the week aerator pumps or using an impeller pump. You CAN cause damage with an impeller pump...they are no joke.

Incorrect. I currently have a piggy back system but my previous systems used Jabsco pumps. I am aware of the power of these pumps but I always have the lockers open when filling. It's not hard to keep your eye on the bags.

Edited by old skool malibu
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Incorrect. I currently have a piggy back system but my previous systems used Jabsco pumps. I am aware of the power of these pumps but I always have the lockers open when filling. It's not hard to keep your eye on the bags.

Why even have the lockers open? Just fill and do other stuff.

It's not expensive or hard to do a proper vent. What is the real justification for not doing it properly? What are you gaining? You are willing to spend 80k+ on a boat but not $25 in parts to do it right (probably less since you have existing vents you can tap into).

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By having a vent you cannot suck the bags completely dry. That is my driver. My buddy's added vents and we both agreed that not venting worked out better as we had the lockers open on his boat as well. Guess we are just better at multitasking then you :)

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By having a vent you cannot suck the bags completely dry. That is my driver. My buddy's added vents and we both agreed that not venting worked out better as we had the lockers open on his boat as well. Guess we are just better at multitasking then you :)

sure you can suck the bags dry with a vent. Check valve on vent line. This really shouldn't be up for debate.

  • Like 2
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sure you can suck the bags dry with a vent. Check valve on vent line. This really shouldn't be up for debate.

This. Check valves aren't expensive. Mine suck down dry with check valves.

Multi-tasking is great until you get distracted by something (such as a kid running around the boat), then your saving a couple bucks will cost you hundreds. Pass.

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sure you can suck the bags dry with a vent. Check valve on vent line. This really shouldn't be up for debate.

It's not a debate it's personal preference. Sorry Pal

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It's not a debate it's personal preference. Sorry Pal

No no... I get that to vent or not is a personal preference.

But whether a vented bag will drain flat is not debatable. It will. Mine do.

  • Like 1
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