Arrow sack install question regarding how many vents used?

[Miljack]

I'm about to plumb in an overflow arrow sack in our 230, and wanted to ask those of you who have installed the sack in the locker, how many vents did you use? The reason I ask is that the picture of the sack shows a bunch of fittings, maybe the sack itself only has a couple of options, but figured someone here would know.

Also, those who are utilizing the overflow line to fill and empty, how many are using PVC in the bottom of the bags to allow airflow to help vent the hard tanks while emptying? What size?

thanks,

[HS]

I used one vent line, and I used the vent fitting nearest the fill fitting to guard against loss of airflow. Having observed the fill and empty cycles a few times, i noticed the rear arrow leg does not collapse during the empty cycle so i feel confident not using any pvc pipes. I used the same approach with the 750s in the aft lockers -- placing the vent line in the fittings nearest the fill fittings. I did the install recently so glad to answer any questions.

[xrichard]

My install: input to the bag from the hard tank over flow goes to the fitting on the bottom of the rear of the arrow sack. For venting, I used the fitting at the top rear of the arrow sack and the one at the front point of the arrow sack....I tied those together with a 1" line and then "T"'d off the middle of that line to vent out the side of the boat. I think it would have worked just as well using only the front fitting, but I figured I'd have a better chance of getting all the air out using both fittings and it dramatically reduced the chance of the bag collapsing all the way to prevent air flow on draining. I ignored the fittings on the outside points of the arrow.

WRT pvc, I used 2x cross drilled pipes in both of my rear locker bags and still had problems where they collapsed such that air could not flow through the bags to vent the hard tanks. When this happens, the hard tanks compress and you can bend the tank sensors (this happened to me a couple of times...it gets expensive). I ended up solving this problem by making sure the bag couldn't collapse all the way---this can be done by using a bungie or other line to keep your vent fitting from being able to collapse all the way onto the bottom of the bag or by simply cutting your vent hoses so they won't allow it. In the back, I used bungies to keep the vent fittings up, and in the front I cut and routed the vent hose so it won't let the bag collapse all the way down.

One other bit: my belly tank burst a seam and was replaced under warranty. I'll never know, but I wonder if a contributing factor was the extra back pressure created by having the arrow sack between the OEM tank and the vent. Just in case this was a problem, I "T"d into the vent line that runs from the hard belly tank to the arrow sack and ran this extra vent to a new fitting that vents over the side. Thus, the backpressure on the OEM hard tank is reduced dramatically when filling. Once the hard tank is full, it pushes some water out this additional vent, but the bulk of the water fills the arrow sack. When the arrow sack is full, the back pressure increases significantly and both vents (for the hard tank and the arrow sack) push out all excess water in equal amounts. For draining, I installed a check valve on the hard tank vent...so the valve allows water and air to flow out, but closes in the other direction. If you don't have a check valve, you won't be able to drain the arrow back because the pump would rather suck air from the vent than suck water from the bag.

[Miljack]

For 230 arrow sack users, does the "leg" come all the way to the back of the locker? Mine looks about 12" to 15" short of the back wall of the locker, is that what most of them look like?
Also, the belly tank in our boat is black, and looks like one big "u" shape, is that what the tank looks like on most of your 230's? My friend's 210 looks like the tanks are split in the middle.