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SD-Diesel08

Multiple Pumps per bag?

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SD-Diesel08

Dear Crew,

So i have been reading many threads and hiding in the shadows. I do not have a boat yet but am hoping that in this upcoming off season to be able to get into a new LSV. I've been getting excited and trying to get all the upgrades lined up. I'm looking at upgrading the ballast system, adding bags to the rear lockers and the option for a bow bag as well. The thing that seems annoying to me is the fill times and drain times that it takes for the additional bags. Now I am a mechanical engineer by degree and trade so i'm fully aware of why these things take so long, but I'm not experienced in ballast systems yet so I wanted to raise a question to the crew and see if there is a way to speed this up...

So, lets say money not an issue (it is but lets pretend for a second), is there a way to run two fill pumps per ballast bag? Is there enough power in the boat? Are there enough fittings on the bag to do this? Is there enough space for the extra pump? If you went with reversible pumps I believe that the same pump fills and drains so would you just need two inlets and a drain correct?

Lots of pumps...

Looking at a bag like this...

http://www.wakemakers.com/ronix-eight-3-plug-nplay-ctn-800.html

Two drain holes (to me) means two reversible pumps.

So run two of these per bag:

http://www.wakemakers.com/johnson-ultra-ballast-pump.html

Seems like it would work...You could wire the two pumps on to one switch pretty easily too.

Edited by SD-Diesel08

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minnmarker

There's plenty of power. Pumps draw less than 15 amps but you might want to start them a few seconds apart. Then it's a matter of how many holes you want in the bottom of the boat and how many pumps and hoses you want filling up space in the boat. If you're filling bags in an enclosed space be sure to shut the pumps off when they fill the space. If you only have one vent line it might not keep up with the pumps.

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tdelandsheer

A few issues with this. You can get around them and make it work just not sure it would be worth it.

Issue one is number of water lines. Each pump will need its own line into the bag. If you use reversible pumps that mean your bag will have two pump lines and one vent line. Reversible pumps use the same line to drain and fill. 3 lines per bag is doable just don't want to "y" them together. If you use a "y" then you are loosing cross sectional flow area and slowing your flow.

Also because you want to avoid "y"s you will need to double the number of through hulls.

You could argue that the water will just flow faster before and after the "y"s and to a certain amount it will. However this is only true to a point. It will take a lot more force to push all that water through a small opening and you would loose some of the flow from your pumps. If you loose flow then this doesn't really make sense.

The next issue you will have is running two pumps on one switch. Jabsco's set up sends all the power through the switch. If you put two pumps on one switch you double the power draw and are asking for a melt down. Can be fixed with a relay.

The last issue would be running them all at once. With my old battery I could only run two reversible pumps at once with the engine running. I now have 2 deep cell batteries and can run all 4 pumps but I don't think I could do 8. Not sure on this one because I don't know anyone that has ever tried it.

In the end I can fill two 500 rears 300 bow and about 400 ski locker in under ten minutes and drain just as fast. It is time spent sitting on a lake which is always good. This is doable just not sure it would be worth it.

edit:Power draw on a reversible pump is a lot more then aerators.

Edited by tdelandsheer

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jb 156

I think 2 pumps per bag is a little overkill, I run one per bag on my 750's and fills and drains plenty fast.

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SD-Diesel08

A few issues with this. You can get around them and make it work just not sure it would be worth it.

Issue one is number of water lines. Each pump will need its own line into the bag. If you use reversible pumps that mean your bag will have two pump lines and one vent line. Reversible pumps use the same line to drain and fill. 3 lines per bag is doable just don't want to "y" them together. If you use a "y" then you are loosing cross sectional flow area and slowing your flow.

Also because you want to avoid "y"s you will need to double the number of through hulls.

You could argue that the water will just flow faster before and after the "y"s and to a certain amount it will. However this is only true to a point. It will take a lot more force to push all that water through a small opening and you would loose some of the flow from your pumps. If you loose flow then this doesn't really make sense.

The next issue you will have is running two pumps on one switch. Jabsco's set up sends all the power through the switch. If you put two pumps on one switch you double the power draw and are asking for a melt down. Can be fixed with a relay.

The last issue would be running them all at once. With my old battery I could only run two reversible pumps at once with the engine running. I now have 2 deep cell batteries and can run all 4 pumps but I don't think I could do 8. Not sure on this one because I don't know anyone that has ever tried it.

In the end I can fill two 500 rears 300 bow and about 400 ski locker in under ten minutes and drain just as fast. It is time spent sitting on a lake which is always good. This is doable just not sure it would be worth it.

edit:Power draw on a reversible pump is a lot more then aerators.

Yea the extra holes in the bottom of the boat is one concern. I don't think it would compromise the structure at all...Just have to be careful drilling into a brand new hull. Power is definitely a concern and i wouldn't have to wire two pumps on to one switch if it would be too much draw. And i would definitely keep from doing a "Y" fitting. No real benefit. It could actually have a negative effect. Trying to force twice as much fluid through the same size hole is like trying to cram twice as many people through the same door...wouldn't help at all. So two separate inlets is the way to go.

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tdelandsheer

Yea the extra holes in the bottom of the boat is one concern. I don't think it would compromise the structure at all...Just have to be careful drilling into a brand new hull. Power is definitely a concern and i wouldn't have to wire two pumps on to one switch if it would be too much draw. And i would definitely keep from doing a "Y" fitting. No real benefit. It could actually have a negative effect. Trying to force twice as much fluid through the same size hole is like trying to cram twice as many people through the same door...wouldn't help at all. So two separate inlets is the way to go.

I agree if you do all those things this would work great, and should cut your fill time in half. Basically your are setting up two full drain and fill systems for each bag. My only worry would be having that many extra failure points (house clamps to come loose, through hulls to leak, pumps to die). If you are generally short on time when trying to get ready to ride and a few minutes would make a difference I think this is a great option.

If it meant the difference for me getting to ride and not during the week I would definitely do it!!!

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BuNewb

if you want 2x speed, I would recommend aerator pumps which would get you close to that and be much cheaper. However, I have reversible in my boat for ease of installation.

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SD-Diesel08

I agree if you do all those things this would work great, and should cut your fill time in half. Basically your are setting up two full drain and fill systems for each bag. My only worry would be having that many extra failure points (house clamps to come loose, through hulls to leak, pumps to die). If you are generally short on time when trying to get ready to ride and a few minutes would make a difference I think this is a great option.

If it meant the difference for me getting to ride and not during the week I would definitely do it!!!

I mean a few mins here or there definitely won't make or break a day on the water or keep us from riding or anything. It would be nice to fill faster but there are definitely some risks. Leaks being a big one but on the flip side i think having two pumps is good for redundancy purposes, as well as if each pump is theoretically doing half the amount of work to fill the same bag they should last longer and be worked less.

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Mpuppy

Here is a pic of what I did. I removed the rear t-drain and added two more aerator pumps with a shut off valve. According to a water flow chart I found, the 3/4" hole at zero head pressure is more than big enough to supply the two pumps. The hoses run to the top of the rear ballast bag. I haven't timed it, but what a difference in fill time it makes.

post-23713-0-74919600-1442605711_thumb.j

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Brad B

And if you use a boat with a paddle wheel speedo pickup - remove it and replace with gps pickup - then use that bigazz hole for 2 pumps or even a manifold with multiple pumps.

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minnmarker

And if you use a boat with a paddle wheel speedo pickup - remove it and replace with gps pickup - then use that bigazz hole for 2 pumps or even a manifold with multiple pumps.

Good idea. How big is that hole?

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shawndoggy

assuming you are going to surf listed, weighting just one side at a time, one way to get two pumps filling is to do one reversible pump for each bag in your boat, and then a crossover pump that pumps between the rear sacks. Effectively this gets you two pumps filling and two pumps draining. For instance if you are empty, you fill both bags and after a minute or so (once there's water in both bags, you also turn on the xover pump to the bag you want to fill. Do the opposite for draining. I did this on my last boat and it was 5-6 minutes to fill an 1100.

You definitely want to spring for bags with two bottom ports if you go this way, so you avoid sucking air. Those bags are slightly more but not cost prohibitive.

The system on my old boat was setup to fill and drain through the bottom of the boat. Only the vent went over the side. This is the simplest, and almost least expensive way (no vent at all is obviously cheaper), and has very few plumbing problems. The only thing to look out for is running the pump dry on the drain side... which is really something that could happen just as easily if you drain out the side.

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Brad B

The hole where the paddle wheel was is 2" I believe

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