Adding Fat sacs to factory ballast 2007 VLX

[Ronnie]

Which way works better? Wakegirl's method or Ronnie's method.

I'm going to install 400lb v-drive bags this weekend on top of existing hard tanks in a 2007 VLX and prefer not to do alot of testing/re-plumbing.

Not sure my way would work or not, I can't test it on my boat. That was just a quick drawing to help sort out the problem that was being discussed. I have added some 750 sacs in my lockers since that post but I do not have the underfloor tanks. I do have a problem with water siphoning out of the sac through the empty line. My line runs from the drain pump, up under the gunnel and back down to the thru hull. Once water is forced out that line from the weight of the water in the bag, it starts siphoning. You need a way to stop the siphoning. The only way I know of is a ball valve or some way to introduce air into the line to break the siphoning effect without letting it start again. I'll probably put in a ball valve on that line.

Do we need to change your screen name to Current VLX Owner?

[Now a VLX Owner]

Do we need to change your screen name to Current VLX Owner?

Ya, how do I do that?

[Ronnie]

Do we need to change your screen name to Current VLX Owner?

Ya, how do I do that?

PM one of the Admins or Mods and request a name change, include the name you want to use. If you will PM me I'll get it done for you.

[Now a VLX Owner]

Ok all,

I installed the 400 lbs Fly High V-Drive bags this weekend. I plumbed the the hard tank vent line to the bottom fill port on the bag and then plumbed the top vent port of the bag to the through hull. The fill and vent ports are forward in the boat to make plumbing easier since that is where the hard tank ports are as well as the through hull vent. The bags seemed to fill fine but on the right side I had water coming out of the drain port on the hull while filling. Not a big stream of water but more than a trickle. Why is this happening?

The other problem I had was draining the bags. When the system stoped draining the hard tanks were empty and about 2-3 inches of water remained in the bags. I had to pick them up to tranfer the remaining water to the hard tanks. Is there a way around this? I was wondering if a shut off valve was installed in the vent maybe a vaccum would be created while draining therefore suck the remaining water into the hard tank versus only gravity doing the work.

[dalt1]

I have plumbed my 750'S the same way. Vent to bottom front of bag and top front of bag out to front vent fitting on side of boat. After filling hard tank and about 1/3 of bag the water will start pushing past the fill pump and out the hull drain line. Don't know how or why this happens. I put a ball valve in the drain line right at the drain fitting and just close it during filling. That cured that problem. I still use my portable pump on my top rear bag fitting if I want to fill or drain faster. When switching sides, I pump from one bag into the other plus run factory fill pump. I have quick disconnects on all fittings so switching pump is a snap.

[WakeGirl]

....

One other thing that I just thought of....it's going to require a little help as the bag gets close to the bottom since as the bag gets less full, the pressure to push the water down into the tank will lower. So as it gets toward the bottom, the bag may need some help.

Ok all,

I installed the 400 lbs Fly High V-Drive bags this weekend. I plumbed the the hard tank vent line to the bottom fill port on the bag and then plumbed the top vent port of the bag to the through hull. The fill and vent ports are forward in the boat to make plumbing easier since that is where the hard tank ports are as well as the through hull vent. The bags seemed to fill fine but on the right side I had water coming out of the drain port on the hull while filling. Not a big stream of water but more than a trickle. Why is this happening?

The other problem I had was draining the bags. When the system stoped draining the hard tanks were empty and about 2-3 inches of water remained in the bags. I had to pick them up to tranfer the remaining water to the hard tanks. Is there a way around this? I was wondering if a shut off valve was installed in the vent maybe a vaccum would be created while draining therefore suck the remaining water into the hard tank versus only gravity doing the work.

This was one of the potential issues that I mentioned earlier in the thread. As the bag empties, there is less & less pressure to force the water down into the tank.

I'm not sure on your filling issue. Does it happen if you can keep the vent line up a little bit?

[Now a VLX Owner]

....

One other thing that I just thought of....it's going to require a little help as the bag gets close to the bottom since as the bag gets less full, the pressure to push the water down into the tank will lower. So as it gets toward the bottom, the bag may need some help.

Ok all,

I installed the 400 lbs Fly High V-Drive bags this weekend. I plumbed the the hard tank vent line to the bottom fill port on the bag and then plumbed the top vent port of the bag to the through hull. The fill and vent ports are forward in the boat to make plumbing easier since that is where the hard tank ports are as well as the through hull vent. The bags seemed to fill fine but on the right side I had water coming out of the drain port on the hull while filling. Not a big stream of water but more than a trickle. Why is this happening?

The other problem I had was draining the bags. When the system stoped draining the hard tanks were empty and about 2-3 inches of water remained in the bags. I had to pick them up to tranfer the remaining water to the hard tanks. Is there a way around this? I was wondering if a shut off valve was installed in the vent maybe a vaccum would be created while draining therefore suck the remaining water into the hard tank versus only gravity doing the work.

This was one of the potential issues that I mentioned earlier in the thread. As the bag empties, there is less & less pressure to force the water down into the tank.

I'm not sure on your filling issue. Does it happen if you can keep the vent line up a little bit?

I added check valves in the vent lines and the bags seem to drain better now. I think a small vaccum occurs helping to suck the water from the bag into the hard tank.

I still can't figure out why I have water coming out of the drain port on the hull while filling the RH bag. The vent lines on the LH and RH side are routed to the same height and are below the height of the drain hose. The LH side works fine. In theory the water height in the bag needs to be higher than the drain hose routing height in order for the water to come out the hull. The drain hose is rounted about 10 inches higher the the top of the bag. I'm thinking about adding ball valves to the drain ports but would prefer not to do this.

[G-Wake]

....

One other thing that I just thought of....it's going to require a little help as the bag gets close to the bottom since as the bag gets less full, the pressure to push the water down into the tank will lower. So as it gets toward the bottom, the bag may need some help.

Ok all,

I installed the 400 lbs Fly High V-Drive bags this weekend. I plumbed the the hard tank vent line to the bottom fill port on the bag and then plumbed the top vent port of the bag to the through hull. The fill and vent ports are forward in the boat to make plumbing easier since that is where the hard tank ports are as well as the through hull vent. The bags seemed to fill fine but on the right side I had water coming out of the drain port on the hull while filling. Not a big stream of water but more than a trickle. Why is this happening?

The other problem I had was draining the bags. When the system stoped draining the hard tanks were empty and about 2-3 inches of water remained in the bags. I had to pick them up to tranfer the remaining water to the hard tanks. Is there a way around this? I was wondering if a shut off valve was installed in the vent maybe a vaccum would be created while draining therefore suck the remaining water into the hard tank versus only gravity doing the work.

This was one of the potential issues that I mentioned earlier in the thread. As the bag empties, there is less & less pressure to force the water down into the tank.

I'm not sure on your filling issue. Does it happen if you can keep the vent line up a little bit?

I added check valves in the vent lines and the bags seem to drain better now. I think a small vaccum occurs helping to suck the water from the bag into the hard tank.

I still can't figure out why I have water coming out of the drain port on the hull while filling the RH bag. The vent lines on the LH and RH side are routed to the same height and are below the height of the drain hose. The LH side works fine. In theory the water height in the bag needs to be higher than the drain hose routing height in order for the water to come out the hull. The drain hose is rounted about 10 inches higher the the top of the bag. I'm thinking about adding ball valves to the drain ports but would prefer not to do this.

I have 750's in the back of my VLX. Both drain lines leak during filling. I had to put ball valves in. Realistically not a big deal, but it is a little nuisance to have to do every time we fill and drain.

[Now a VLX Owner]

Anyone know of a good brand/model 12 volt solenoid valve to add to my drain line instead of a ball valve. I would prefer to keep the system operational from the drivers seat.

[WakeGirl]

I've looked into this in the past & it seemed that Ebay was the best source.

[zornman]

I haven't been able to find an affordable 12v solenoid valve, but I have been looking at trying a 12vdc/110vac inverter & then connect it to a transformer to get 24vac to run an irrigation valve. That can be done for about $40 plus $20 additional per valve.....of course, I have yet to drill the first hole in my boat.

[WakeGirl]

I think the biggest issue with those solenoid valves is how much restriction that they may introduce into the equation. Something to think about.

[Ronnie]

You could use oversize valves ($). Just getting them to respond to 24v with 12v in the boat. I wonder if you could run a switched circuit in series with two 12v batteries, since most of us have at least two, just for 24v valves?

I just use my shut off ball valves in the bottom of the boat when the sac is full. You've just got to remember to open them when you want to fill again.

[Now a VLX Owner]

All,

I found a good fix for poor draining of bags when plumbed to the factory hard tank via vent line. Replace the 3/4 hose with 1.0 " between the hard tank and the fat sac. This makes a huge difference in drain time. The bags will drain complete. The black re-enforced 1.0 hose can be purchased from FLY High. The 90 degree 3.4 NPT 1" barb fitting which needs to be changed on the top of the hard tank can be purchased from West Marine. Changing the fitting on the top of the hard tank is a little tough. Much easier with a helper.

[txwakejunkie]

How do you keep water from sloshing out of bag through thru hull and how do you drain? Also what drains first?

Gravity. It shouldn't shlosh out. Its basically the same set up as the stock one. On the stock system all there is is a line coming out of the top of the tank (overflow line) to the through hull. Now you will have a line coming out of the bag to the through hull.

When you go to drain gravity will force the water out of the bag back into the ballast tank.

I put the same set up in my boat this winter. Haven't had a chance to test it. This is a real basic mod.

Good luck

Exactly. It's about the simplest way to add bags to these boats, but like I said it's going to be relatively slow because the stock tank has to fill first. Then the bag will fill from pressure, but it would slow down as the pressure increases since you're filling from the bottom. There's probably a way around that, but I haven't put a ton of thought into that one.

Could you fill from the top of the bag and have the bag fill the tank as it fills. You have a hose attached from the bottom of the bag to the old overflow on top of the tank any way so it should fill the tank as the bag fills up.

Here is a crude drawing. I'm not sure if the water would be pushed out the tank vent line while it was filling but if it looped high under the gunnel would it not vent higher than the water level in the bag? The pump wouldn't pressure the tank until the bag was full. The pressure would come from the weight of water in the bag.

Somebody else take a look at this and see if it would help the problem Wakegirl is referring to. I don't have the floor tanks so I can't test it out.

Is anyone filling there 750 like ronnie has got here in the pic? I am going to be doing this over the winter and this looks to be the easiest way. How long does it take to fill?

edit: the pic did not copy over, it is on the first page.

Edited November 10, 2008 by txwakejunkie

[bubbs20]

anyone around that was able to do it?