3/4" hose vs 1" hose

[gorilla]

Hey, looking to upgrade my pumps to 1100 or 1200 gph pumps, but will still have to reduce them to 3/4" to mate up with the factory hoses. Does the 3/4" hose reduce the gph of the pump? I am planning on keeping 1" as long as I can, but will have to reduce them at some point. Any info would be greatly appreciated. Thanks.

Brian

[Bozboat]

If I am thinking clearly the volume of a 1" hose or pipe should be about 43% more than a 3/4 inch hose or pipe. Someone on here should have some math skills.

Edited May 18, 2012 by Bozboat

[gorilla]

If I am thinking clearly the volume of a 1" hose or pipe should be about 43% more than a 3/4 inch hose or pipe. Someone on here should have some math skills.

I was thinking that too, but does it really reduce fill and empty times that much? I have read that it was within a few minutes for the 2 pumps (800 vs 1200) on an 1100 lb bag.

[Bobby Light]

You will not reduce your fill time anywhere near 43% doing the switch.

[gorilla]

Well, I figured out that the only spot that will be using a reducer is for my drain. Gonna get an 1100 pump and make it 1" all the way to the bag and gonna use a 1200 drain that will reduce to 3/4" right at the thru-hull.

[Bawshogg]

Basic fluid mechanics here boys. Your system will only flow as fast as it's smallest orrifice will allow. It doens't matter if you plumb in 3" tubing if the fitting at the bag is still 3/4". You can only get in/out what the fitting size of the bag will allow. You will see a small difference in using the larger pump, but noit really anything I would consider as worth it. Adding another pump to the drain and fill would go waaaayy further than waisting time with all the fittings and re-plumbing for the larger tubing.

[Bobby Light]

Well, I figured out that the only spot that will be using a reducer is for my drain. Gonna get an 1100 pump and make it 1" all the way to the bag and gonna use a 1200 drain that will reduce to 3/4" right at the thru-hull.

Are you gonna drill 1" thru hull fittings for fill, and does your bags have 1" fittings? These are things you need to make it worth your while.

[skibreeze]

Basic fluid mechanics here boys. Your system will only flow as fast as it's smallest orrifice will allow. It doens't matter if you plumb in 3" tubing if the fitting at the bag is still 3/4". You can only get in/out what the fitting size of the bag will allow. You will see a small difference in using the larger pump, but noit really anything I would consider as worth it. Adding another pump to the drain and fill would go waaaayy further than waisting time with all the fittings and re-plumbing for the larger tubing.

There is more to consider though. Last weekend I was using an impact wrench to remove my wife's tires. When using the 3/8" hose, it didn't have enough air to break the lug nuts loose, and as soon as I switched to a 1/2" hose, they broke loose. So there is more to it as you can clearly see.

Just today, I was swapping out some of my 3/4" to 1" and going from aerater to a reversable pump on my 2 1100 lb bags.

The 3/4 fittings going into my bags had thicker sidewalls than the 1" fittings, so there is still a benefit in physical size of the opening going into the bags. Also, it is possible that the reversable pumps are able to deliver water at a higher pressure, which would also preform better .

I wish that I would have gone with 1" the first time.

[NorrisMike]

Sooo..... it sounds like the 800gph pumps are already at the max flow rate for these type of pumps using 3/4" fittings? Just thinking out loud here - but if that's the case then what if you just changed over to all 1" and kept the stock pumps? If you could get the max flow out of the stock pumps then you should be able to fill/drain your 1100lb sac in approx 10 mins. If you could max out the flow rate with a 1200gph pump then you should be able to fill/drain your 1100lb sac in just under 7 mins.

If it takes you 3 hours total to make the swap then after 30 boat outings of filling/draining you will start to see a return on your investment.. HAAHAHA!

[Bradley Thornton]

If it takes you 3 hours total to make the swap then after 30 boat outings of filling/draining you will start to see a return on your investment.. HAAHAHA!

Time at home worth $0 per hour time on the water price less.

[gorilla]

Are you gonna drill 1" thru hull fittings for fill, and does your bags have 1" fittings? These are things you need to make it worth your while.

the 3/4 NPT ball valves are about the same size as the 1" barbed hose fittings on the inside, so minimal restriction there. I am putting in one of the Rule 1100 into the factory ball valve and running 1" hose completely to the bag. The Rule has a 3/4" NPT on the inlet and 1" barb on the outlet, so does the new Piranha pumps. That means they are OK with the factory sized ball valves being 3/4" NPT. I have new fittings on order and I am hoping this is all worth it. I am having the Rule 1100 fill my 1100lb bag and my factory 800 fill the 400lb tube sack. Shouldn't take too long.

[malibudog]

Not really. Physics are physics. Compressed air is not a valid comparison here. Air can be compressed.... water, fluid, oil, cannot be.Your example sucks amd most likely your wimpy compressor cannot deliver enough CFM through a smaller hose. As pressure goes up, yes, you will flow more fluid through a given orrifce, but these type of pumps that he is refferring to are not positive displacement pumps, they put out good volume, just not high pressure.

Bobby: I have always been curious about this. When I looked it up a year or so ago, I found lots of references to head loss and friction loss of fittings. Generally, what I thought I understood was that the effect of a small fitting on flow rate is not to effectively drop the whole pipe to the same size as the interior of the small fitting, but rather just to increase the head loss in a manner that can be equated to making the big pipe longer. Thus, I thought what I understood was that changing to 1" pipe, even with 3/4 fittings was worthwhile. One of the supposedly knowledgeable ballast retailers also told me this was the case, and that flow rate loss required you to look at the diameter of the pipe restriction AND for what length the pipe was restricted. Maybe 800 or even 1200 gph aerator pumps will not push enough water through 3/4 inch; tubing to even make a difference in head loss/friction? It certainly seems like if I disconnect a 3/4 line and hold it overboard, the pressure is not that high? Sounds like you may know through experience or training - I was just trying to noodle it without either

[SkiZilla]

Basic fluid mechanics here boys. Your system will only flow as fast as it's smallest orrifice will allow. It doens't matter if you plumb in 3" tubing if the fitting at the bag is still 3/4". You can only get in/out what the fitting size of the bag will allow. You will see a small difference in using the larger pump, but noit really anything I would consider as worth it. Adding another pump to the drain and fill would go waaaayy further than waisting time with all the fittings and re-plumbing for the larger tubing.

Not really. Physics are physics. Compressed air is not a valid comparison here. Air can be compressed.... water, fluid, oil, cannot be.Your example sucks amd most likely your wimpy compressor cannot deliver enough CFM through a smaller hose. As pressure goes up, yes, you will flow more fluid through a given orrifce, but these type of pumps that he is refferring to are not positive displacement pumps, they put out good volume, just not high pressure.

No its been a few years since I have done serious fluid dynamic calculations but I as I recall its not quite this simple. Orifice size does directly affect flow rates but so does hose diameter. Friction factors restrict flow in hoses and pipes and are inversely proportional to diameter (ie. as diameter goes down, friction factors grow). Assuming a laminar flow profile (I believe its reasonable to expect a Reynolds number of less than 2000 in a ballast system) boundary layer conditions dictate that the velocity of the fluid at the walls of the pipe be zero and the flow profile expands to in a parabola like shape to full velocity in the centre of the pipe, effectively reducing the cross sectional area of the tube and "choking" the flow of the hose. So a 3/4" hose of any substantial length will flow less than a 3/4" orifice and by changing to a 1" hose we dictate that the governing flow restriction is actually the 3/4" bag or hull fitting.

Just my thoughts on the matter....

[Bobby Light]

No its been a few years since I have done serious fluid dynamic calculations but I as I recall its not quite this simple. Orifice size does directly affect flow rates but so does hose diameter. Friction factors restrict flow in hoses and pipes and are inversely proportional to diameter (ie. as diameter goes down, friction factors grow). Assuming a laminar flow profile (I believe its reasonable to expect a Reynolds number of less than 2000 in a ballast system) boundary layer conditions dictate that the velocity of the fluid at the walls of the pipe be zero and the flow profile expands to in a parabola like shape to full velocity in the centre of the pipe, effectively reducing the cross sectional area of the tube and "choking" the flow of the hose. So a 3/4" hose of any substantial length will flow less than a 3/4" orifice and by changing to a 1" hose we dictate that the governing flow restriction is actually the 3/4" bag or hull fitting.

Just my thoughts on the matter....

I agree, what you've described is Bernoulli's Principle. The water flowign through a 1" hose then hitting the 3/4" fitting is the Venturi effect but the difference in diameter isn't enough to make a huge difference. Bottom line it'll work but don't expect huge differences in fill time.

[gorilla]

I looked and I can get a 1" thru-hull for the drain. So, the big bag is gonna be all 1". Smaller bag is gonna stay 3/4" and that will be just fine. Thanks guys.

[JohnnyDefacto]

No its been a few years since I have done serious fluid dynamic calculations but I as I recall its not quite this simple. Orifice size does directly affect flow rates but so does hose diameter. Friction factors restrict flow in hoses and pipes and are inversely proportional to diameter (ie. as diameter goes down, friction factors grow). Assuming a laminar flow profile (I believe its reasonable to expect a Reynolds number of less than 2000 in a ballast system) boundary layer conditions dictate that the velocity of the fluid at the walls of the pipe be zero and the flow profile expands to in a parabola like shape to full velocity in the centre of the pipe, effectively reducing the cross sectional area of the tube and "choking" the flow of the hose. So a 3/4" hose of any substantial length will flow less than a 3/4" orifice and by changing to a 1" hose we dictate that the governing flow restriction is actually the 3/4" bag or hull fitting.

Just my thoughts on the matter....

I agree. At work we flow water through 1 1/2" hose through 1 1/2" couplings (fittings)... but we also have 1 3/4" hose through the same 1 1/2" couplings and there is a HUGE drop in friction loss when going with the 1 3/4" hose, therefore increasing flow volumes tremendously. Granted we are talking about hundreds of feet of hose and higher pressures (120-250 psi), but the physics is the same in your application. I think you will see a measurable difference in fill and empty times.

Please do a few before and after tests with a stop watch if you can. I may make that upgrade this winter as well.

[TallRedRider]

I agree. At work we flow water through 1 1/2" hose through 1 1/2" couplings (fittings)... but we also have 1 3/4" hose through the same 1 1/2" couplings and there is a HUGE drop in friction loss when going with the 1 3/4" hose, therefore increasing flow volumes tremendously. Granted we are talking about hundreds of feet of hose and higher pressures (120-250 psi), but the physics is the same in your application. I think you will see a measurable difference in fill and empty times.

Please do a few before and after tests with a stop watch if you can. I may make that upgrade this winter as well.

At those pressures you are in a whole 'nuther league. If we had those pressures on our wakeboard pumps we could put a huge amount of water through even just a 3/4 inch hose. According to this site, at high pressures, you could get 2,160 GPH at high pressure through a 3/4 inch hose!!!!!! At low pressure we are talking 660 GPH.

http://flexpvc.com/W...nPipeSize.shtml

But a real world test has been done. Mike from Mike's liquid audio did a real world comparison on Tigeowners. I think this is the only real world study I have ever seen. I will just copy and paste it:

Ballast Pump Flow Comparison

I was able to finely get some time this weekend to do some flow comparisons amongst some of the common ballast pumps used.

In this test, I used an Attwood Tsunami T800, T1200 and a Rule 1100 All 3 are common live-well style Aerator pumps used for ballast installs.

I have been wanting to do this anyway, but it moved to the forefront this weekend when it was posted in another thread that the Rule pumps were always over rated, as there is no standard of measuring that is used. Well, doing some investigation, I fond two interesting things: 1) Rule does not list a standard of measurement used to rate their pumps (but that doesnt mean they are over rated). The next bit of info was the most interesting. I found that Rule is under the same parent company as Jabsco, ITT Flow Control, and that in the flow rating for the Jabsco, there to is no std of measurement listed. So, is it safe to say that the Jabsco Ballast Puppy too is over rated?????? Well, we will have to answer that question later, as I did not break out the only Puppy I have on hand and test it, but i will here at some point.

Here is how I laid the test out. I tried to make at as real-world as possible, so I set up a mock ballast setup.

I used a Fly High W713 v-drive sac rated @ 400 lbs

5 gal bucket fed by hose as water supply

deep-cycle battery with 2A trickle charge

5' fill hose from pump to top of sac

2' hose from vent on top of sac.

The water supply was lower then sac, typical of a ballast install, and the vent was higher then sac. Sac was drain dry between each test. The clock started as soon as the pump was turned on, and the clock was stopped as soon as I had a steady flow from the vent. Each pump was run 3 times to get an average. For the Rule and T1200, I used 1" hose and 1" fly High quick-connect fittings. For the T800, I used both 1" and 3/4" hose slid over the threads, as well as 3/4 hose on the supplied 3/4" barbed fitting. For on of the T1200 tests, I also used the Fly High W747 3/4" sac valve threads x 1-1/8" Tsunami threads adapter.

Rule 405FC 1100 GPH pump. 3/4" threaded inlet and a 1-1/8" outlet and 1" hose: 4:29 avg fill time.

Attwood Tsunami T1200 pump. 1-1/8 inlet and 1-1/8 outlet and 1" hose: 4:37 avg fill time.

Attwood Tsunami T1200 pump. 1-1/8 inlet and 1-1/8 outlet and 1" hose and W747 adapter: 4:44 avg fill time.

Attwood Tsunami T800 pump. 3/4" inlet and outlet with 1" hose. 4:57 avg fill time.

Attwood Tsunami T800 pump. 3/4" inlet and outlet with 3/4' hose and 3/4 Fly High quick-connects. 5:11 avg fill time

Attwood Tsunami T800 pump. 3/4" inlet and outlet with 3/4' hose and 3/4 Fly High quick-connects and the supplied 3/4 hose-barb connection on the outlet of the pump. 5:25 avg fill time.

Two surprises, here! 1, the Rule 1100 was actually faster then the Tsunami T1200. Not by alot, but IMO, certainly not well over rated 2, the W747 adapter did not slow the T1200 flow down as much as I expected. This is great news, because with the use of the adapter, you can easily mate this pump right to a 3/4" thru-hull setup, and not loose a ton of volume.

Again, this was not meant to be scientific, but simply to compare these pumps flow rates in what is as close to a real world situation as possible. So, take the info with a grain of salt.

__________________

Mikes Liquid Audio: Knowledge Experience and Customer Service you can trust-KICKER, WetSounds, ACME props, FlyHigh ballast & Barefoot Int, Alpine, Sony And More

Edited May 19, 2012 by TallRedRider

[TallRedRider]

And if you want to read the whole thread, then it is here:

http://www.tigeowners.com/forum/showthread.php?t=13621

[Ronnie]

We did similar tests a couple of years ago before I went to Johnson pumps. It was surprising how much the flows changed with any change in lift height on the aireator style pumps.

[TallRedRider]

I just got done swapping out my center tank ballast system for a Johnson pump system. I am a believer. It has been a lot of work. I first swapped the Pirahnas for Tsunami 1200's with 1 inch hose and a 1 inch antisiphon valve ($50!). That decreased my time from 10-11 minutes to about 8 minutes. Today was my first time out, and now I am at 6 minutes for the big center tank. I am pretty stoked! I could not believe the difference in the output through the discharge port, much faster. I think as Ronnie said, I can't help but think that the head pressure from being down in the bottom of the hull all the way to the rubrail on the dishcarge really slows down the Tsunami. Now that I have revamped my ballast system a second time, I have several Tsunami pumps and a 1 inch antsiphon valve for sale. I am now thinking I should swap the surf sack (currently with 2 Tsunami 1200's) for a Johnson.

[DOOFUSisaCAT]

pi are squared not round

by enlarging the hose/pipe/conductor diameter, you can greatly increase the volume of flow thru that pipe.....a simple increase in diameter..say from 1" to 1 1/8" is an increase in cross sectional area of 23%...which is what boat makers did to shaft size several years ago. A small increase in diameter, increased the cross sectional are by nearly 25%...so going from say 1 1/2" to 1 3/4 would not only substantially increase your cross sectional area, but would greatly reduce your head loss over the same distance...given the N values stayed the same.

As far as the lone fitting, you'd experience a negliable amount of head loss, but would act as say a fire nozzle....your psi and cfm inside the hose or pipe would equal that as it crosses or exits the nozzle. That is why when the hose is open ended water will flow out say 3 or 4 feet...but when you put your thumb over the opening, hence creating a venturi, the pressure increases and water shoots much further say 10+ feet.

Edited September 2, 2015 by DOOFUSisaCAT

[Simo]

Larger hose = less friction loss and faster fill times. The longer the hose the bigger difference it will make.

[JohnnyDefacto]

Did you end up doing this? How did it turn out?

I did a similar upgrade on my boat last month. Had 3/4" thru holes all around, 3/4" 800 gph piraña pumps all around, 3/4" fittings to fly high sacs with 3/4" ports.

Estimated fill time for approx 850 lbs in each locker (200 hard tank and a 750 that filled to only 650) was 10 minutes (I unfortunately never timed it but this is a rough estimate)

drain time was at least 15 minutes (prob closer to 18) length of drain time partly due to the gravity drain of sack into hard tank.

I pulled my hard tanks out and put in Sumo 900's (fill completely which is about 1000 lbs according to the test done on wakeworld)

they have the 1" ID ports.

I put in piranha 1100's for my fills, they have the 3/4" inlet and 1" ID outlet, direct swap with my 800's.

Ran 1" I.D. hose through a check valve then directly to top of sumo 900. This line is 1" from pump to sack, only 3/4" at the inlet of pump and thru hull hole.

I put in tsunami 1200 drain pumps, have 1" inlet, 1" outlet, and will take either 1" or 1 1/8" hose. I used 1" hose from drain pump up to the drain port thru hull. 1 foot before the thru hull I used a 1"-3/4" reducer, and then out the 3/4" thru hull.

I used the original 3/4" vent line, just changed out the quick connect elbow with a 1" thread.

Fill time was approx 10 min. for 850 lbs. Fill time now is 6:36 seconds for 1000 lbs. (times it twice, once after install on Fake a Lake in my driveway, once on the water while not moving.... will try it at idle speed just for fun) So essentially my fill time was cut in half

Drain time was 15-18 minutes (guessing, it was a long time. I would hit "drain" as soon as last rider fell or the last time, then short drive to dock to unload everyone, then short drive to ramp, load boat, pull out to parking lot, wipe down..... it would still be draining) maybe 20 minutes... just guessing. too long anyhow.

Drain time now is 8 minutes. So cut it down less than half the time.

Both the drain and fill have a 3/4" fitting, but going with a higher capacity pump and bigger hoses did not seem to hinder the system at all.

The drain water shoots out the side of my boat 3 x's farther than it did before.

[minnmarker]

Attwood Tsunami T800 pump. 3/4" inlet and outlet with 1" hose. 4:57 avg fill time.

Attwood Tsunami T800 pump. 3/4" inlet and outlet with 3/4' hose and 3/4 Fly High quick-connects. 5:11 avg fill time

Attwood Tsunami T800 pump. 3/4" inlet and outlet with 3/4' hose and 3/4 Fly High quick-connects and the supplied 3/4 hose-barb connection on the outlet of the pump. 5:25 avg fill time.

It seems like there was little increase in time going from 1" to 3/4" hose. Only 5% more time.

I'm planning to install a 3 pump system with reversible pumps feeding two 750s in the stern and one bow bag. Thinking one 1-1/4 thru hull to supply all 3 via 1-1/4 tube to 1-1/4 x 1 Tees to the pumps. I'm not worried about 2 or 3 minutes to fill or drain but would like to have a more compact install and 3/4' tubing between the pumps and bags would be a lot easier. Does anyone have a reversible pump system with 3/4" hose?

Another question: If I use 1" hose for the feed/drain hose do I have to use 1" for the vents? As long as I don't ignore water pouring out the side ports there is no danger of bursting anything, yes?

[Brad B]

Using Tsunami 1200 gph we changed to 1" mainly cuz it had the 1" (or so) out and I had a bunch of braided hose leftover from a waterfall project fro the wife.

We did notice fill time decrease of a few minutes.

Left the drain pumps with the 3/4" hose cuz it was easier to add a reducer than to crawl around and refit the thru hull outs and they are 3/4" anyway.

So - using TSUNAMI 1200s - fill one side and drain the other at the same time - the fill beats the drain by about 6 minutes.