Fat sac fill/drain rate research...

[majestic]

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

Look at Duffy's ballast install he used them.

[Ewok]

Thanks, I just got done with that thread, don't know how I missed it.

[chpthril]

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. !

Providing that your ballast sac has enough ports to accommodate the 2-port fill "Y" setup. Fly High's standard sacs only come with 3 ports, so if someone is using aerator pumps, they need a minimum of 3 ports: Vent, drain, fill. So to fill through 2 ports using the "Y", a forth port would need to be added. Adding ports to a standard sac can be done though.

If working with a custom sac built to your own specs, no worries, we can add as many ports as needed and placement as wanted.

Also, dont forget to factor in an extra male and female quick-connect set, so this mod will be about $23.50 p/sac.

Lots of great info here, thanks for taking the time and posting up.

[IDBoating]

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

Yep, that's the Rule 17A, which is what Duffy (up in Sandpoint) used in his system. They're fast, but also HUGE. They take 1.5 inch hose and yesterday he told me it's roughly the same size as the battery. I really wanted to use them but wasn't sure I could find a way to guarantee they'd be self-priming (below the waterline). Duffy didn't care about that since he plumbed his input pumps to the transom. That's why I went with the Rule 29B - it's a nice balance between speed and size.

[duffymahoney]

If you want to switch sides fast then a transfer pump between sacs is the easiest. The 3800's are huge pumps and 1.5" hose is a pain to deal with, but the end result is wow it's fast.

[Ewok]

Here is my plan, I worked on it last year with Chpthrill and got the transfer idea from you guys. I'm thinking about having an extra crossover or transfer line between the sacs with manual shutoffs that I could reach through the engine compartment. Gravity would help a bit with the fill and drain of the sacs when switching from side to side. Chp talked me into the W719 because I actually use the storage under the seats and I like to use the cooler as well. I'm not changing anything with the ballast in the bow, for now. I'm on the fence about which pumps to use. Chp suggested using the existing thru-hulls and add a manifold to them and run pumps to fill the surf sacs from the opposite hard tank manifold so that they get full flow from the thruhulls. Any thoughts or considerations I should worry about? Thanks.

[IDBoating]

Remember our discussion regarding transfer pumping? Here's my idea, it uses two aerator pumps between the two aft sacs and requires an extra fill and drain port on each sac. Actually, you could probably T off of a single drain port on the sac so you really only need an extra fill port on top.

On each side, install a pump next to a drain fitting and run that pump's output hose to an input fitting on the opposite sac. Wire this new pump in parallel with the FILL pump of the opposite sac. Each pump is thus plumbed to draw water out of one side and fill it into the other.

To switch surfing sides, switch to FILL on one side and DRAIN on the other as usual and the existing pumps will start doing their thing. But the side that is filling will also be receiving water transferred from the draining side. Some of the draining sac's water will be pumped into the now-filling sac, and the rest will be dumped overboard. Both sacs have two pumps working on them, yet you only have three pumps operating. You have two pumps filling on one side, and two pumps draining on the other.

* If it's the first session of the day and the opposite sac is empty, nothing happens (aerator pumps can safely run dry).

* If you're ballasting for wakeboarding and thus filling both sacs, you'll be running four pumps - two filling and two transferring. The water flows from the two transfer pumps will offset each other so everything will work the same as always and take the same amount of time as usual. Yes, the two transfer pumps will be consuming some power but if you're loading up for wakeboarding you'll be running the engine soon anyway so the battery will be recharged.

* When it's time to drain both sacs, you'll be draining with the existing two pumps and, again, everything will work the same as always.

In short, everything will work pretty much the same unless you are filling one side and draining the other (changing sides). In that case, your time will be cut roughly in half. And it will happen automatically, with no new switches and no new valves. Just flip your existing switches and the pumps take care of things.

The advantage of this setup is it requires no extra switches, no extra valves, and no extra holes in the boat. It can be retrofitted into an existing system if you have available sac ports. Cost is also quite low (a couple of aerator pumps, some hose, and a few fittings).

Just an idea, hope it helps.

[duffymahoney]

I actually designed fittings into my sac for this exact concept. Here is my drawing. I decided my fill and drain times are good enough though.

[IDBoating]

Great minds think alike!