Thru haul question

[dagansty]

Getting started on a automated ballast system but need a few questions answered as I only want to do this once. I will be going with the reversible pumps. One for port side and one for starboard side. My question is can both pumps be fed from one thru haul intake if it is 1in. Drilling one is nerve racking enough let alone 2. I'm ok with the piping but should the venting be crossed to prevent water escaping while the boat is listed to one side while surfing. Any info would be much appriciated

[Thegerman618]

I am not sure about using a single thru-hull for 2 separate reversible pumps. But after you drill one the second one is much easier. Not to mention your gonna have to drill at least 2 more for the vents so what is one more? As for the vent lines, yes the standard procedure for aftermarket ballast installs is to cross vent the bags. it will take a bit more time (and hose) to do it but will save you the frustration of passive draining in the future.

[talltigeguy]

I think it depends on your boat and the sacks that you put in there. If your sacks fill the compartment to the brim, you need to crossvent. I installed a custom sack in my old 24V and just made sure to have a high loop that was well above the top of the sack and it did not passive drain. But that sack left about 6-8 inches of space in the compartment.

Most guys don't do it, but a single thru hull would work fine for 2 pumps. MLA, the ballast king did some research on different hose sizes and it made some difference to go from 3/4 to 1 inch, but not as much as many of us think it would. 1 inch hose can actually handle a LOT of water. Keep in mind the internal diameter of the pump inlet is only 1/2". If it were me, I would drill another hole, just for simplicity sake.

[chpthril]

A 1" thru-hull can supply 2 pumps with ease. Both based on the flow rate of a 1" thru-hull and secret others have not yet though of. Some will tell you it will burn the impellers up. Ive been building ballast system for years, with no issues. To back this up, I still have some black rubber impellers in stock. Jabsco and Johnson have not used black in years. In fact, they have used, green, I think a blue and now orange, since black. I just dont get many calls for a burned impeller.

Cross venting is not normally needed in a from-scratch ballast build, even with tall custom sacs. There are design factors that can prevent passive draining on most system.

[chopper515]

I have a 1-1" thru hull feeding 3 tsunami 1200 aerators. I just tested it last weekend and while filling 1 600lb sac it took around 6-6.5 minutes and while running all 3 it took around 8 minutes. So it really didn't slow it down enough to worry about. I suspect you wouldn't see any difference in fill times with 2 impellers on 1-1" intake vs. 2.

[dagansty]

So to fill in a few blanks. its a 2007 rz2 with no ballast so this will be from scratch. my plan is to use 1 in thru hull with one ball valve then split with a Y fitting with a check in each line as I want to drain out the side of the boat for visual confirmation that it is complete. With not cross venting I'm assuming that it will need to have an inverted loop to stop the passive draining, this would be much easier pipe run if this is the preferred method. I also will need to decide on bags and I read here on the forum that MLA has custom rz2 sacks so will need to have a convo about them. For now just want to install a 2 bag system and may add the bow sack later on. I would love to know if any one is using a cross over pump and does it save a lot of time switching sides. thanks to all that have replied.

[chpthril]

Just not, to do the dump out the side, it takes 3 check valves per sac. Having said that, I dont suggest it. I did a few, trying numerous check valve styles, and never got it to work as good as i felt it should. Pumps have priming issues and low flow due to air leaks. In the end, the weak link is the check valves.

MLA also does custom ballast kits, and can help you with the design.

A transfer pump basically doubles the flow rate as you are filling a sac with two pumps. At the same time, you are also draining the other sac, with 2 pumps.

When mocking up the tru-hull for the initial install, envision that 2nd thru-hull/ball-valve setup and where its going to go. Need room to assemble, tighten it down and clearance to rotate the handle. This can effect where the first one goes in.

[dagansty]

With out using the check valve what stops the water from entering or leaving when the pumps are off. Do the pumps have internal checks or relying on the impeller holding back the water. Say the bag is full with about 900 to 1000lbs of water that's a lot of water to hold back. I was only considering using 2 check per bag. One on the inlet and one on the drain side. How will you know if the bag is empty with out opening the hatch to monitor it progress. Like I said I haven't started or ordered anything as of yet so very open to better suggestions. Just would like it to automated and dummy proof.

[BCRider]

You easily have the room for two new holes if you want to keep them separate. Last weekend I pulled the bottom Tsunami pump in the picture out and rotated the current set up to the 9 o'clock position. After the ball valve I installed a T so I can add a third pump for my starboard side sac. Currently my port side MLA sac is dual fill/empty. I rarely run goofy but I wanted to plumb in a third pump as previously the sac and hard tank were connected together. That was ok when it was a 400lbs sac but last year I put in a 900 and it was really slow and ended up reworking it to throw over the a pump over side to fill which gets old quick. So this years plan was to get a third in for the starboard side.

Regardless of what I'm doing you have lots of room in the bottom of the boat. It just takes some planning. Once you got one hole done it's easy to do a second. I put the thru hulls where I did to stay away from the transducer which is inline with the 90 deg outs of the pumps back where the motor mount is. I also had to angle them back because of the floor panel and the height restrictions.

PS: Ball valves are getting swapped out Mike

[dukesofhazzard]

You can search my posts too and you will see where I tee'd into the stock thru haul so I didnt have to drill anymore. Works great. Take MLAs advice he has helped a lot of us. You can also see where I mounted the pumps etc.

[talltigeguy]

I like having my boat pee over the side of the boat, like a man, instead of under the boat, like a girl. My last ballast install in my Malibu, I used check valves and had it discharge over the side. Just like MLA said, I had occasions where a check valve failed and I could not fill. So as much as I am obsessed with gender issues on my boat, if I do reversible pumps again, I will just have it discharge out the bottom.

And an impeller pump has enough stiffness to the impeller to prevent any passive filling.

[chpthril]

I like having my boat pee over the side of the boat, like a man, instead of under the boat, like a girl. My last ballast install in my Malibu, I used check valves and had it discharge over the side. Just like MLA said, I had occasions where a check valve failed and I could not fill. So as much as I am obsessed with gender issues on my boat, if I do reversible pumps again, I will just have it discharge out the bottom.

And an impeller pump has enough stiffness to the impeller to prevent any passive filling.

Better not haul your boat to NC, there might be issues when its time to discharge the ballast

[dagansty]

OK so ill plan for 2 thru hull but will make one of then 1.25 so if in the future i want to plumb in front bow bag. still confused about no check valve as with the bag full at 1000lbs that the pump impeller can hold that amount of force back with out draining some of the bag. So to clairify does the vent line from the bag need an inverted loop to stop passive draining. If there is anyone out in tige land that has a reversible cross over pump that could tell me how much time it takes to switch sides. to all that chimed in thanks been reading a ton and just about ready to start gathering material for install