Dedicated Thru-hulls or a Manifold?

[Juice75]

Anybody have any opinions on if it's better to run a dedicated thru-hull for each pump, or have one thru-hull with a manifold?

It's going on a '99 vlx. Here's my delima...for the two rear fill pumps, there isn't much room on the starboard side of the motor. The raw water intake is a little in the way, and I don't want to put another hole too close to that one. So I was thinking of only using one thru-hull on the port side, and making a manifold for the two rear fill pumps. Is this a good/bad idea?

I'm trying to get all the info I can before I start drill holes in a perfectly good boat.

Thanks!

Oh, and if anyone has any pics of pre-05 ballast systems, feel free to send them my way.

[Chia]

Drilling thru the hull

This thread deals with what you want to know.

I think if you are going to use a manifold, you do not need 2 pumps. One pump to get the water to the manifold and a valve system to get the water to each bag.

the problem I see with putting 2 pumps on a manifold is (when operating one pump) the path of least resistance may be to take water from the other bag (back thru the other pump). If there is no water in the other bag the pump may just suck air.

I could be wrong.

[Juice75]

Thanks for the link. And I didn't even think of the 'path of least resistance' issue. Then I'd have to use check valves and all that fun stuff. Sounds like two thru-hulls is the way to go. Where did I put my drill?

[Pistol Pete]

If you did it with a manifold, I'd be concerned about starving the pumps for volume. I'm assuming you'd be using 700-1100 G.P.H. pumps. You'd have to have a pretty large I.D. manifold to keep them pumping happily. Also, It'd be an easier and simpler set-up to just have two through hulls. I'm talking about diagnosing problems here.

Don't forget, you need to run the supply line uphill well beyond the outside water line or install valves to keep the water from filling the bags while you're underway.

[Juice75]

I'm going to use the Tsunami 1200 gph pumps, and probably 1" thru-hulls. After reading this and a few other posts, I've tossed the manifold idea out the window.

I'll definitely run the fill lines up to the top of the engine compartment then back down. I've read A LOT of posts on here about people having trouble with their sacs/tanks filling while underway. Especially the locker sac.

On the stock setup, does the locker sac have a vent hose, or does it push the excess water out past the drain pump?

[Pistol Pete]

On my boat's stock set-up, it just pushes the water out the drain pump.

[Juice75]

On my boat's stock set-up, it just pushes the water out the drain pump.

Cool. That's one less hose I have to run.

[Chia]

I'm going to use the Tsunami 1200 gph pumps, and probably 1" thru-hulls. After reading this and a few other posts, I've tossed the manifold idea out the window.

I'll definitely run the fill lines up to the top of the engine compartment then back down. I've read A LOT of posts on here about people having trouble with their sacs/tanks filling while underway. Especially the locker sac.

On the stock setup, does the locker sac have a vent hose, or does it push the excess water out past the drain pump?

Let us know how that works out. On my locker sac, which fills while underway (if i don't use the 1/4 turn shut off valve i installed), the fill hose is looped right to the top of the dash in the compartment behind the passenger seat. I think the water pressure produced by boat speed forces the water up the hose the same as if it was coming out of household water tap.