Fat sac fill/drain rate research...

[Timmy!]

This thread delivers!

[IDBoating]

must why he has a blister on his hand

Yeah, I thought KY Jelly was supposed to help prevent blisters.

[IDBoating]

You may be getting the hose hot, but not the coils.

Idea: Take more time heating the hose. Perhaps back off the heat gun a bit and take more time. This will help insure the coils get hot (and soften) along with the clear hose material.

[chpthril]

Idea: Take more time heating the hose. Perhaps back off the heat gun a bit and take more time. This will help insure the coils get hot (and soften) along with the clear hose material.

Exactly, the rubber hose heats faster then the nylon coils. I use medium heat and about an inch off the hose.

[IDBoating]

Exactly, the rubber hose heats faster then the nylon coils. I use medium heat and about an inch off the hose.

And rotate the hose (or the heat gun) so the hose heats evenly all around its circumference.

[talltigeguy]

Sorry I have totally hijacked this thread.

I went to Lowe's and bought a heat gun for $25. Best money spent ever.

Went to the garage this evening and heated up the end of a hose, used pliers to gently stretch it and slid it right on the fitting with some KY. Not too much effort at all. I think what was said above is right, the heat was not enough to get the coils to expand. My first try and I noticed that the end of the hose started to smoke a tiny bit after a short time frame, so I might have even gotten a little exuberant with it. Will watch that hose closely for signs of failure.

In short, the wife can have her blow dryer back. No more blisters for me (now just need to watch for contact burns).

[jason@wakemakers.com]

A little smoke is ok (usually it means the heat gun is too close to the hose), a lot of smoke is bad.

I would recommend using water instead of a lubricant compound, as the water will evaporate and be gone, but the lubricant will stay around and could lead to failure down the road. Probably overkill, but water works just fine.

[IDBoating]

I would recommend using water instead of a lubricant compound, as the water will evaporate and be gone, but the lubricant will stay around and could lead to failure down the road.

That's why I recommend KY Jelly. It's water soluble and disappears in a very short time. A petroleum based lubricant, that would be a bad idea for the exact reason you mention.

[talltigeguy]

That's why I recommend KY Jelly. It's water soluble and disappears in a very short time. A petroleum based lubricant, that would be a bad idea for the exact reason you mention.

Yup. For that same reason, you should not use oil based lubricants for....other activities. Say no to vaseline.

[chpthril]

That's why I recommend KY Jelly. It's water soluble and disappears in a very short time. A petroleum based lubricant, that would be a bad idea for the exact reason you mention.

I agree. I do not recommend using a petroleum based lube on rubber as it will degrade the rubber over time. For just a straight lube, I like to use a 100% silicone lube. It can be found at most any auto parts store and comes in a paste form. Its commonly used for lubing brake caliper slides and spark plug boots.

[IDBoating]

Back on topic...

Now that we've resolved the hose issues....

The 1.125 T and Y fittings arrived today. My calipers show the T as having 0.910 ID while the Y has 0.875 ID. That's a darned small difference but you can actually see it with your eyes in the wall thickness.

All else being equal, I would expect the Y to yield better performance. But since it has a smaller ID I'm not sure what to expect.

For comparison, the hose itself has an ID of just barely over 1.0 inch, though that may be because of compliance by the soft material. The Fly High one inch fittings have an ID of 0.935.

Here's all measurements in one list:

One inch reinforced hose: ~1.0
Fly High fittings: 0.935
"White" Y: 0.670
Sch40 T: 0.760
Rule Y: 0.875
Rule T: 0.910

The baseline of performance is the Fly High fitting. Keep in mind, though, that the Fly High has an immediate 90 degree turn that adds some backpressure. If we can divide the flow before it encounters that 90, we should see some improvement.

The largest multi-fitting I've found so far are the new Rule T's. We were already seeing 12.5% flow improvement with the smaller T's. The new T's are ~20% larger, so something good should happen.

The new Rule Y's are a bit smaller, but they have the advantage of less internal turbulence. I don't know which will prove to be better.

One interesting detail: The Rule fittings are of lower manufacturing quality. They have some internal flashing that will have to be sanded/filed smooth to avoid turbulence. The other fittings are nice and smooth.

I hope to run the actual experiments this weekend sometime. I'll publish results when I have them.

[IDBoating]

0.90 inch Y assembly test results...

As promised, I've run flow tests on a Y assembly using the Rule 0.900 ID (1.125 OD) Y fitting. Here's a photo of the assembly:



Note that the threaded fat sac fittings are installed, to accurately reproduce the backpressure, turbulence, and restriction seen by the water when it is actually filling a fat sac. (This presumes the sac is being filled via top fittings, as opposed to bottom fittings where the pump would see a changing water column and thus changing backpressure as the sac fills.)

I'll cut to the chase: The Y assembly yielded a 21% increase in flow. Not bad for an under-$10 modification!

The original, single fitting flows ~0.33 gallons per second. The earlier T fitting flows at ~0.37 GPS. This Y assembly is flowing about ~0.40 GPS. (As a side note, this means I'm getting a real-world ~1440 GPH out of the 1600 GPH rated Rule 29B's... 90% of their theoretical performance, not bad at all.)

An interesting detail about the differences between the two sac interfaces: The traditional single fitting approach shoots the water into the sac with some force and there is visible turbulence in the stream. The Y assembly, however, is more like two medium-strength streams that just fall out of the fittings "naturally" - and they are crystal clear, with no turbulence at all. I liken the single fitting's stronger stream to the effect you get by putting your finger over the end of a garden hose; you get distance at the expense of volume. We want maximum volume in a ballast system and don't care how far the stream shoots into the fat sac, and it appears a sufficiently large Y can deliver that.

It bears mentioning that I smoothed out some internal manufacturing irregularities in the Rule Y with a rattail file and some emery paper. I also tapered the ID of the input side so it didn't present a flat annular ring to the incoming water. These mods took just a few minutes on the relatively soft and thin plastic.

If your fat sac takes eight minutes to fill, this Y assembly will knock that down to about 6.5 minutes for less than ten bucks and no extra pumps nor throughhulls. Obviously multiple pumps will always win, but you cannot beat this option for simplicity and ease of retrofitting. And if you want to minimize the number of holes in your hull, or cannot find room (in the boat or in the budget) for more pumps and their associated thruhulls and ball valves, this setup provides a clean way to shave about 20% from your fill time.

Hope this helps someone... thanks!

[duffymahoney]

I love my Y system.

[IDBoating]

I love my Y system.

You HAD to use Y's because of your pump's 1.5 inch output!

My thoughts here are directed more toward folks with traditional 1.0 or 1.125 inch output pumps and single fat sac fittings. I've long wondered if we mere sub-1.5inch mortals could gain some performance by letting our single pumps drive multiple fittings. Now we know the answer.

You know, Rule's comments on that pump you used say something like "lots of volume but very low pressure". I wonder what flow you would have gotten if you DIDN'T use multiple fittings, and all that flow was trying to get through the native 3/4 inch ID. Did you ever try that?

[Ewok]

Anyone read or hear about this pump when they were researching their pump options? 3800 gph seems pretty quick.

http://www.iboats.com/General-Purpos...-view_id.70247