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Ndawg12

Finally going reversible

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Ndawg12

And I have a few questions after researching some old threads about reversibles, hose diameter, etc.

1) I read that Shawndoggy had his 3/4" vent fitting blow off confirming that his 1" fill is definitely moving more water than 3/4". I'm not too concerned with speed but don't want this happening to me either. Was this just a fluke or has anyone else experienced this as well? If I stay with a 3/4" vent would I be better off staying with 3/4" fill/discharge hose?

2) Would I be gaining anything by going with 1" from the wye fitting to the pump? If so then I think I can get a 3/4 to 1 barb to barb fitting and I assume I'd want that as close to the wye fitting as possible.

3) I want to drain out the existing drain thru-hull, does this sketch look accurate to make that happen?

Appreciate all advice.

Nate

IMG_0453_zpskniyo7fi.jpg

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Murphy8166

I seem to remember the thread years back....

Well - glad you are finally making the change.

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Brodie

I would put a check valve on the drain hose to prevent sucking air when filling.

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Murphy8166

I don't see any point in the "y'd" off drain hose...

Those impeller pumps create a water / air tight seal.

Also don't see any point in going to 1" vent hose unless you go 1" all the way - which your drawing does not indicate...

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Murphy8166

If it were me - I'd go 3/4 thru hull to 3/4 nipple to 3/4 ball valve to 3/4 male thread to 1" hose barb to 1" hose to 1" fitting into the bag.

On the vent side - go 3/4" all the way!

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tdelandsheer

1) i wouldn't worry about vent line size. a 3/4 line can let plenty of air out for your 1 in fill.

2)by going 1 in to the pump you could gain a little but you will still have "choke" points in the system.

3)in your sketch each bag has 3 thru hulls. yes this will work but this is not needed using a few one way valves will allow you to tee the drain into the vent line.

Congrats you will love this when done though.

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shawndoggy

Your diagram will suck air through the side drain on fill without a check valve, won't it?

I would just do 1" all around. Side drain isn't necessary, and just adds more points of failure (three check valves instead of one). Let it drain under the boat and keep it simple.

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tdelandsheer

I agree the drain under the boat is simpiliar with less failure points. You do also end up checking your sacs to see if they're drained at the end anyway. I wanted to drain above water was my only reasoning.

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Ndawg12

Your diagram will suck air through the side drain on fill without a check valve, won't it?

I would just do 1" all around. Side drain isn't necessary, and just adds more points of failure (three check valves instead of one). Let it drain under the boat and keep it simple.

Oops, yes you're right. I thought side drain was the cool, TMC approved way to do it. Does sound alot simpler.

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Ndawg12

I forgot to mention that I'm completely removing my rear hard tanks, I guess I'll have a couple unused thru-hulls if I bottom drain.

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Murphy8166

I forgot to mention that I'm completely removing my rear hard tanks, I guess I'll have a couple unused thru-hulls if I bottom drain.

Are you going to use the exsisting thru hulls for the drain/fill port? I did this with a drain plug and it worked well.

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MLA

1) I use .75" hose and outlet on all my system and have never had one blow off or create any sort of issue. With a reversible pump, the flow rate between .75 and 1" will not be that much difference. The difference will rather be the velocity of the water. So bottom line, stick with a .75" vent if you like.

2) the difference between .75" and 1" hose at the pump, is the .5" NPT fitting that threads into pump housing, rather then the 1" hose that slips over. Go 1" for all the fill/drain plumbing between the intake and sac.

3) the diag is missing all the check-valves to make it happen, but no worries, I would toss the idea and just dump the drain water right back through the intake. Ive done a half dozen of these setups and they have all been problematic. The 3 check valves are the weak link. They leak either air or water, depending on the pump direction, resulting in either slow flow or the pump not priming.

The OEM .75" thru-hulls will not be an issue, so no worries reusing them.

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shawndoggy

If you are paranoid... And if you have an extra unused through hull anyway... You could always double vent the bag.

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Ndawg12

Ok, never thought I'd say this but TMC has talked me into doing something cheaper and easier. So is it really this simple?

IMG_0454_zps0hknicyn.jpg

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Ndawg12

Are you going to use the exsisting thru hulls for the drain/fill port? I did this with a drain plug and it worked well.

Yes, I've actually added 2 3/4" thru-hulls for the piggy back system I'm using now. There's like 6 3/4" holes in the bottom of my boat :crazy:

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windy1

why do you need a check valve on the vent hose.

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Murphy8166

So that the sac can suck flat when emptying.

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BlackBluMalibu

I did mine like your latest drawing. Works great and after a few fills and empties, you can time and know when things are full and empty.. Works really well! Have fun and safe boating!

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Ndawg12

What size breaker should these Johnson pumps be on, I'm guessing 15 or 20...?

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Murphy8166

I'd go 25 or 30 on them. Have you thought about using the circuit breaker (push button) on the drivers side. Did mine that way - no issues!

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hunter77ah

Ok, never thought I'd say this but TMC has talked me into doing something cheaper and easier. So is it really this simple?

IMG_0454_zps0hknicyn.jpg

Just curious, does it matter which side of the hose is longer (Intake-Pump or Pump-Sac)? Should the pump be closer to the intake? Or should they be evenly spaced?

If limited to 3/4" intake, why go with 1" hose?

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saburkhart

Mine is like your second drawing and I think the only issue with distance is to make sure your pump is below sea level. At least that was my consideration. I think the pump would prime itself if it were a little higher, but I placed mine low enough to make sure the pump did not starve

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Ndawg12

I'd go 25 or 30 on them. Have you thought about using the circuit breaker (push button) on the drivers side. Did mine that way - no issues!

Thought about it but not sure I have anything freed up that size. I'm thinking about doing an external fuse block and bypassing the driver panel. Next question, is the wiring for aerator pumps adequate for these Johnsons?

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tdelandsheer

I don't believe aerator pump wiring is large enough. Reversibles draw a good amount more power.

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