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store934

Passive draining through the vent lines

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store934

I have some fly highs that when filled the tops are pretty much level with the top of the tray over the engine.  From what I can tell they keep draining the top 4-5 inches of water because the vent line is run underneath the gunnel so when completely full they naturally drain to the vent line height.   I have not looked into it yet but I am really doubting being able to move the vent line / loop any higher and certainly not as high as the top of the bag when it is full.   Right now I just keep kicking on the rear pumps after every set to keep them full and they slowly drain out...   I guess I could plug the vent line or add a valve but I am hoping for an less manual solution.  Any ideas?

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Josh4mc

I have the same issue with my 23 LSV. I haven't spent enough time looking at it to figure out a solution but while at Lake Shasta I plugged the through hulls with wine corks to stop them from draining. :whistle:

Monitoring for a permanent option.

 

P.S. I did find that letting the non-surf side drain naturally and then filling the surf side from time to time(or plugging it) the surf wave showed improvement.

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teamerickson

Get the vent line as high as you can in the front of the locker. It needs to be higher then the bag.

Did the bags have vent lines?

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minnmarker

Of course this won't help if you already have holes in your boat but I put my vent holes above the rub rail. They look fine and integrate well with the fuel caps in the back and with the logo in the front. No passive draining even with full 1100s in the rear lockers.

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store934

No vent line on the bags.  May do that in the spring since I have to burp them.   Vent line is from the hard tank.  Two hoses on the bottom of the bag fill and drain the PNP (2016 Malibu design).

So even if I vent he bags in the existing vent line it will not solve the problem since the vent line and drain are lower than the top of the bags.  Maybe my only hope is to get the vent line up higher in the gunnel.

Guess I could consider capping the hard tank  vent line on the rears and just venting the PNP.  Might have a better shot at a higher route.  Only problem with that is then these bags are really full I am not sure I can route a line since the top or locker is pretty much sealed off by the bag / flush with the top of locker.  I could see it pinching pretty easy.

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teamerickson

Yeah, try and get the line up high in the gunnel. 

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Ndawg12

Not sure sure how it's all plumbed but could you add ~15' of hose and run it as far as possible toward the front of the boat and secure the "loop back" up as high as possible under the gunnel?  As the bags fill the transom sinks and helps your cause...unless you're running a bunch of bow weight.

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Fman

It would be very easy to add one of these ball valves to each vent line.  I did this on my last boat with bow bag for the same problem you are having.  It is a manual solution but would definitely help the problem.

https://www.wakemakers.com/pvc-ball-valve.html

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The Hulk

well i have a 2016 and i can see the vent line is (in front of the bags) so when bow is rising the vent line should be higher than the front of the bag, but also i have a 2016 so my vent line is from hard tank only and NOT the Bags...thus i dont have the issue but need to burp. 

one thing this thread is making me consider is the following. 

when i burp the bags i take the caps off to do it quicker push the bags down then seal em up and call it close enough. but if the bag was vented the entire time it was filling then the vent line would NOT need to be nearly as big as what they are (i'm guessing here)

i'm looking to tie my bags into the same vent line (at highest point in the gunnel) with a T connection but i'm considering using maybe half the size tube maybe instead of 1/2" tube i could use 1/4" tube, my thinking is that it should be harder for the syphon effect on smaller tube and or at least drain much much slower. Also second thing is if i use 1/4" line into 1/2" line then again its going to be HARDER for the siphon affect to take place as once the waterflow goes into the bigger 1/2" line it wont fill the entire 1/2" line and thus air will be in there to break the siphon....that may very well be enough...however if not how about below idea: 

Also why not add a gore-tex Vent (similar to anti-siphons on the ballast) this would allow air into the vent tube stopping the siphon affect at the top of the gunnel but if you do fill the bags and forge to turn off the pumps and water starts coming out the vent lines it wont go into the boat due to the gore-tex vent. https://www.gore.com/products/categories/venting

Gore-vent.jpg

Edited by The Hulk

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Capdoogie

Went to Home Depot. Bought 4 cork stoppers.  Fill bags, turn off pumps put in stoppers and surf all day with no ballast leak!

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Capdoogie

Put in vent and drain line hole outlets on both sides

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racer808

I just used corks on my Bu.  I don't seem to have the issue with my MB but I think it has more to do with how far the vent line is being there is no loop

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MLA

Given the layout of the plumbing, id say of there is passive draining from the tank vent due to the height of the sac, there will be passive draining through the drain line as well. 

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teamerickson

I think MLA could be right. Thinking about how I fixed it with my T22, I got both the vent and drain line higher then the bags in the front of the locker.

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granddaddy55
On 11/4/2016 at 11:52 AM, mikeo said:

I've used these kinetic air vents on the bags in my lockers:

https://www.dripdepot.com/search?q=kinetic air vent

You still need to monitor the bags so you don't overfill and burst them, but if you're going to fill to 100% they work great.

Saw your post before on this snd still have the browser open to it, so the thread opening on my sumos will fit the 1 inch in your link?

this is genius, worst case water dribbles out when bags full and pumps running? The opening for it is slightly lower than bleed/fill valve but it must get the vast majority on its own and then I could push in middle and near end of bag to get the last if any air to the bag, or NOT

Edited by granddaddy55

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granddaddy55
On 11/4/2016 at 11:52 AM, mikeo said:

I've used these kinetic air vents on the bags in my lockers:

https://www.dripdepot.com/search?q=kinetic air vent

You still need to monitor the bags so you don't overfill and burst them, but if you're going to fill to 100% they work great.

Also how would you bust the sacs cause of this vent?  still going to overflow but now will only overflow after sac is full of water instead of when full of air, oh, your not on a pnp? Tied to tank drain and vent ?

Edited by granddaddy55

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mikeo

@granddaddy55 I have dedicated reversible pumps for my add-on ballast; the advantage of the kinetic vent is that once the bag is full (of water) the plastic check-ball floats and seals off the vent. There is a little water that dribbles out when the bag is almost full, but it's less than what people drip in the boat drying off on the engine cover so I don't worry about it.

The bursting issue I have to worry about is if I leave the switch for the reversible pump on and don't pay attention; the check valve will seal and the pump will keep running and burst the bag. I can tell if I leave the pump on right now since the engine divider will pop out of the track and hit against the side of the engine making a loud "bang". I'm trying to find a pressure switch that I can use to turn the pump off when the bag is full; using a timer doesn't work since fill rates vary with altitude, water temperature, battery voltage, etc. Eventually I'll find the perfect configuration, but for now I'll tinker during the off season.

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MLA
6 hours ago, mikeo said:

I'm trying to find a pressure switch that I can use to turn the pump off when the bag is full;

Just install a vent line. When the sac is full it overflows out the side of the boat. Sac wont burst, engine dividers stay in place, impellers dont burn up and you get an audible and visual signal that the sac is full. 

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granddaddy55
12 hours ago, mikeo said:

@granddaddy55 I have dedicated reversible pumps for my add-on ballast; the advantage of the kinetic vent is that once the bag is full (of water) the plastic check-ball floats and seals off the vent. There is a little water that dribbles out when the bag is almost full, but it's less than what people drip in the boat drying off on the engine cover so I don't worry about it.

The bursting issue I have to worry about is if I leave the switch for the reversible pump on and don't pay attention; the check valve will seal and the pump will keep running and burst the bag. I can tell if I leave the pump on right now since the engine divider will pop out of the track and hit against the side of the engine making a loud "bang". I'm trying to find a pressure switch that I can use to turn the pump off when the bag is full; using a timer doesn't work since fill rates vary with altitude, water temperature, battery voltage, etc. Eventually I'll find the perfect configuration, but for now I'll tinker during the off season.

One more time, that 1inch in your link, do you know if that would screw in to my sumos where the factory screw in plug for top venting or filing is, not sure how that's measures 

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mikeo
16 hours ago, MLA said:

Just install a vent line. When the sac is full it overflows out the side of the boat. Sac wont burst, engine dividers stay in place, impellers dont burn up and you get an audible and visual signal that the sac is full. 

...and I get passive draining that leaves only about 60% of the ballast in the boat after one surfing set. I need to figure out a way to get the vent to be above where the top of the ballast is, but with the "max fill" bags the top of the bag is above the rub rail. I may need to look in to running vent hose to the front tank vent to keep it high enough to prevent passive draining.

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minnmarker
13 hours ago, mikeo said:

...and I get passive draining that leaves only about 60% of the ballast in the boat after one surfing set. I need to figure out a way to get the vent to be above where the top of the ballast is, but with the "max fill" bags the top of the bag is above the rub rail. I may need to look in to running vent hose to the front tank vent to keep it high enough to prevent passive draining.

Or get anti-siphon valves and stuff them up under the gunwale.  Or if you don't already have vent holes in your hull then put the vent holes above the rub rail and forward of the bags.

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granddaddy55
On 11/4/2016 at 11:52 AM, mikeo said:

I've used these kinetic air vents on the bags in my lockers:

https://www.dripdepot.com/search?q=kinetic air vent

You still need to monitor the bags so you don't overfill and burst them, but if you're going to fill to 100% they work great.

Just installed , I used o ring of bag plug , it didn't have one, can't wait for this weekend. How elegant! And cheap and no effort or thought other than to listen to a forum member!

they are probably going to minimize any sloshing in slac infilled bags

Edited by granddaddy55

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granddaddy55

@mikeo

+1 for kinetic vent, worked perfect, a little drible sometimes from them when pushing the filling but who cares, if my bag drains were installed correctly and my 50x20x20 850's laid properly, there would be no raising the hatch any more, thus was a $19 dollar with shipping elegant solution 

Edited by granddaddy55

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