Vent or not

[Colorado Boat'n]

Would it be beneficial to add a check valve in the mix or would this not be necessary? I have the bags sharing a fill at the Thru hull under the engine.

Check valve not necessary. Cross venting helps avoid draining while surfing. I.e. Vent your starboard bag to your port side vent and vise-versa. Otherwise, depending on how big your bag is, you dump water out the vent hole when weighted up on just one side when you bag is vented on that side as well.

[FastFreddy]

I used my bilge drain as my vent line. I just Y'd into it with a couple of check valves. Works great.

This way I didn't have to drill an extra hole.

Edited June 24, 2014 by FastFreddy

[jmanst15]

FastFreddy did you vent both bags into the bilge drain??? Thinking of doing the same.

[MLA]

Some of the vent flow will likely run down into the bilge. I would tie into the tank vent.

[MalibuV7]

I have aerator pump system. Check valves on the line but also put on PVC ball valves on the drain and vent lines. If we bloat the sacs for surfing we can shut off the drain and vent lines so we do not drain during riding. This was a quick setup. This winter we are updating the lines to run to the opposite sides. But for now its a cheap easy way to prevent any drain after they are filled for surfing.

[FastFreddy]

FastFreddy did you vent both bags into the bilge drain??? Thinking of doing the same.

Yes I did.

[FastFreddy]

Some of the vent flow will likely run down into the bilge. I would tie into the tank vent.

Not if you use enough check valves. I used three check valves, one per vent and one for the bilge drain. I used the wakemakers check valves and they hold very well.

[shawndoggy]

does a blige pump have enough head pressure to push past a check valve?

[jb 156]

Even with a vent i blew out a fitting, left the pump running while surfing. Can't imagine not venting a bag.

[MLA]

Not if you use enough check valves. I used three check valves, one per vent and one for the bilge drain. I used the wakemakers check valves and they hold very well.

A check valve for the bilge line is about $20, where as a thru-hull is under $10. I do like using a check-valve in the vent line for a more complete drain, but to share the t-hull with the bilge, a check valve is a must. It make more sense to to share with the drain t-hull, as opposed to the bilge.

[MLA]

does a blige pump have enough head pressure to push past a check valve?

Yes. Some even include them as part of the pump.

[FastFreddy]

I also liked adding the check valve to the bilge line to prevent water from coming back in when the boat is fully listed.