Mojo Ballast re-design

[yooper]

I actually sent an email to Wakemakers to get their opinion, but I'm going to re-post here to see if anyone else has something to add, or has done anything similar.

I have a 2013 Moomba Mojo, and I’m thinking about reconfiguring my ballast system a bit for better performance and maintenance.

The first issue is that all 3 pumps are mounted to a board which is hidden behind the port side ballast compartment. I had a pump get stuck when the ballast was full and my only option was to drain the ballast into the bilge (onto the floor, really) so that I could access that compartment and get the impeller to spin again. I’m thinking about leaving the timer control in that location, but re-locating the pumps to a panel mounted to the inside of the transom, behind the engine. Can you think of any reason NOT to do this? Extending the length of the wires, or any other reason?

The second problem is that each pump is currently mounted in a different orientation so that they will all fit on the mounting board. I don’t know, but I suspect that can affect pump speed. Agree? I also know that orienting the pump with the motor up, and impeller down is the best way for longevity. Mounting behind the engine will give me more room to mount them correctly and also give me access if I need to change an impeller.

I’m also thinking about utilizing check valves so that I can fill my bags from the top, and empty from the bottom port. (I attached a drawing) My theory is that the weight of the water in the sac creates more resistance for the pump and the GPH rate slows down as the sac fills. Am I crazy, or could there be something to that? Or are the pumps just powerful enough that it is a non-issue. While filling from the top, there would be little to no resistance.

Along the same lines, what about re-directing water so it drains out the through hull, above water level? Again, no resistance like you would have from pumping back into the lake underwater. I could use my other top port as my vent.

Are any of these ideas beneficial, or am I over thinking this and making a bunch of work for nothing?

Also, one question you may or may not be able to answer…. Once my ballast timers read 100% on the dash, I usually have one sac that still isn’t full. I can toggle the fill switch and get an extra 30 seconds at a time, but it’s really a pain. Is there a way to override that and get the pump to run until I turn the switch off?

http://i62.tinypic.com/1zl9l3p.jpg

[trayson]

This is what the manufacturer says about pump orientation and location:


Pump should be mounted in a dry, cool

ventilated location.

Pump may be mounted in any position

without loss of efficiency; however, it is

suggested that the pump head be down if

vertical mounting is desired. Mount motor

as close as possible to power source to

obtain full voltage.

I am a big fan of draining above the water line. It's great to have that visual and audible indicator of when it's done draining. Plus it's fun when the kids are swimming on the side of the boat to fill a bag a little and then switch the drain on when they swim by the thru-hull and get them!

I only have 1 reversible on my boat, but I've done the following:
I have 3 different plastic ball valves in line. 1 is for a bag under the surfside bow seat, the 2nd is for a 400 bag that's under my surfside seats (gets used all the time) and the 3rd connects a coiled hose with a non-closing sprayer to the pump. I used it the other day to suck out water from the bilge that the bilge pump wasn't getting. I will also test it to see if I can use it to spray kids as a water gun of sorts. haha.

On my reversible, I have the 2 check valves so I can have the above water line draining as pictured in the diagram:
http://cdn.shopify.com/s/files/1/0106/9702/products/Automatic-Ballast-SystemPrinter1_grande.jpg?v=1397705571



As far as changing the way it fills or drains from the bag itself. My understanding is that the reversible pumps are powerful enough that head pressure really doesn't affect them much and in turn having them fill from the bottom should be fine. I wouldn't waste my resources there.

I have heard you can reprogram the timers, but I don't have timers, so I have no idea. I turn off my switches when water starts coming out the vent lines.

[brain_rinse]

Not a Mojo, but all 3 of my pumps are in the engine compartment on the back wall, mounted motor up/impeller down. I think it makes total sense to do the same with your boat.

You could do an easy test to see how much filling from the top improves your fill times. My guess is that it will make very little difference. One of my favorite part about reversibles is the simplicity, so adding check valves and extra hoses wouldn't be worth it to me unless it was for significant improvement.

Do you know if you have Jabsco timers?

[mmandley]

Moving the pumps to the engine bay is a sound idea.

I don't understand how you will fill through the top of the bag and drain out the bottom when the pump only has a single feed line to the bag.

Also remember the more check valves you add the more you decrease pump efficiency. The check vales do have resistance over an open line.

[jstenger]

I also moved all three of my pumps to the plastic wall between the engine and transom. The pumps are on the engine side, and the controller is on the transom side. None of the wiring had to be changed.

[JoelFett]

I also moved all three of my pumps to the plastic wall between the engine and transom. The pumps are on the engine side, and the controller is on the transom side. None of the wiring had to be changed.

I would be totally OK if you could include a picture of said relocation. Also, how much hassle was getting around the engine to do this mod, since its gonna be even more fun with the additional size of the Raptor in my case.

[yooper]

All good feedback. Thanks, guys.

I'd also like to see a picture of your re-location, Jstenger.....

[moombadaze]

I moved my pumps and controller from that back wall, I installed them on the inside of the engine divider wall -2 on one side and 2 on the other side of the engine. no issues at all doing this. I am in the process thou of moving the pumps to board located behind the engine above the muffler. only reason is easier access to changing out the impellers

I would not bother with filling from the top and empty from the bottom of the bag--not worth the hassle.

I do like the idea of the empty water being discharged out the side vents--I may do this yet. may come down to how much hose is needed to do the bow tank/ibs

go into your menu setting and adjust your timers-do this before filling the bag. typically one minute equals 100lbs, then set if for 30 seconds xtra fill time-this will help when emptying

add the check valve to your vent line for the rear bags only- your bags will empty 100% and look like a giant raisin. ****don't put one on the front infloor tank vent line**

[csm]

If you have any pumps mounted with the impeller on the top, it's asking for trouble. If the impeller housing leaks, it goes down into the motor, and the pump will go bad. This happened to me with how my pumps came from factory. I reconfigured my pumps so that one is sideways, and the other two have the impeller down, motor up.

[trayson]

since its gonna be even more fun with the additional size of the Raptor in my case.

LOL. I'm having a hard time feeling sorry for you on this one!!!

[gregski]

The second problem is that each pump is currently mounted in a different orientation so that they will all fit on the mounting board. I don’t know, but I suspect that can affect pump speed. Agree?
I can't think of any reason that the orientation would effect speed.


I’m also thinking about utilizing check valves so that I can fill my bags from the top, and empty from the bottom port. (I attached a drawing) My theory is that the weight of the water in the sac creates more resistance for the pump and the GPH rate slows down as the sac fills. Am I crazy, or could there be something to that? Or are the pumps just powerful enough that it is a non-issue. While filling from the top, there would be little to no resistance.
This is actually the opposite of reality (but don't feel bad, it's a very common misconception). The best way to think about pumps is that they have to work to lift/push water vertically against gravity. If you pump water up 3', it's the same amount of work for a pump whether it goes through a hose or a huge tank. The total volume of water in the tank doesn't create resistance, only the vertical water column. If it were a hard tank in which the fill outlet was always at the top, then the pump would always be working against the full vertical water column (3' in this explanation) whereas when filling from the bottom, the pump would first work against 0', then 1', then 2' of water and only 3' at the very end and thus it would be faster since it could do more filling with less resistance.

In fact there are a couple of reasons why your proposed system would be less efficient than just filling/draining through the bottom:
1. There would be slightly less resistance pumping up 3' through a huge tank than 3' of tube because the tank is almost like a really large diameter tube - smaller diameter tubes have more resistance.
2. There would be a check valve that introduces additional resistance.


Along the same lines, what about re-directing water so it drains out the through hull, above water level? Again, no resistance like you would have from pumping back into the lake underwater. I could use my other top port as my vent.
This is actually the exact scenario I described for a hard tank. Draining out the bottom would definitely be faster. Think of it like this: gravity is already pushing the water down. If you just had a straight hose connected to the bottom of the hull the bag would drain until the water level in the ballast was equal to the lake. Pumping the water up higher than the water line that is more work for the pump than (but maybe you want to visually see the water emptying like Trayson described).

[yooper]

Wow. Great reply. Appreciate it.

[newty]

Pump orientation does matter. At some point the carbon seal will leak. If the seal is up then it is less likely to leak. if it leaks then it just drips over the pump housing. If the seal is down and the motor is on the bottom then when water leaks it will drip right down the pump shaft into the windings of the motor causing premature death.
Ask me how I know...

[jstenger]

All good feedback. Thanks, guys.

I'd also like to see a picture of your re-location, Jstenger.....
http://i1217.photobucket.com/albums/dd382/Joestenger/20140422_182455.jpg (http://s1217.photobucket.com/user/Joestenger/media/20140422_182455.jpg.html)

[yooper]

Looks great! Exactly what I had in mind... Although, only the middle pump is oriented the way everyone recommends, with the electric motor above the impeller. I'm going to strive to get all 3 like that.

[JoelFett]

I like what you did there, but like he said, the pump orientation is a concern of mine. Good work though. Unfortunately, I don't have near the room to accomplish that so I'll have to figure out my next option. My engine compartment is way different looking than that. Damn the bigger engine (it's hard to say that without smirking though...)

[yooper]

I like what you did there, but like he said, the pump orientation is a concern of mine. Good work though. Unfortunately, I don't have near the room to accomplish that so I'll have to figure out my next option. My engine compartment is way different looking than that. Damn the bigger engine (it's hard to say that without smirking though...)

Yeah, that's hilarious..... ;)

[moombadaze]

Joe, did you brace the bottom of the board or did yours come that way---mine didn't, thinking about just adding a couple more thru bolts to help support that board now

[jstenger]

Joe, did you brace the bottom of the board or did yours come that way---mine didn't, thinking about just adding a couple more thru bolts to help support that board now
Yes, I added the braces. Not sure if I needed them, but I had some extra aluminum angle laying around, so I did. They were very easy to make, but lining them up was a little difficult. They bolt to the rear, non folding, side covers. I also added the 4" holes on either side of the pumps to route the hoses thru. I wanted to have all the impellers down, but I decided against it. For one, the impellers are easier to remove and inspect. For another, I wanted the pumps close together in order to make more room for the hoses going out the back. As I stated earlier, the control board is directly behind.

[moombadaze]

I hear you on being easy to inspect and replace, don't ask why I just ordered more impellars with gaskets--let me rephrase that--with damm gaskets, think I found out why my bilge was so full--my infloor tank may not be cracked afterall

[mojo25]

One of my pumps was mounted from the factory with the head up/motor down. It took 3 years to break. I replaced it with a new pump and mounted it sideways on the port mounting board.

[moombadaze]

got all 3 pumps mounted, I put 2 hinges at the top so I can swing the bottom up for servicing of the impellars, put my 4th pump on the inside of the port engine panel that folds down

[yooper]

I got all 3 pumps re-located. The board it is minted to is hinged at the top, and features hand knobs at each side to mount it in place. When the board is lifted up, all 3 impellers are easily accessible for service. I mounted the control box on the wall in the port side compartment.

http://images.tapatalk-cdn.com/15/10/14/ece9a967e1c63a8cda8bf62801db8ae7.jpg
http://images.tapatalk-cdn.com/15/10/14/778e7659f7e2175d93385b60e71dc0eb.jpg

http://images.tapatalk-cdn.com/15/10/14/098422cd93744ad291210c5aba4ec827.jpg



Sent from my iPhone using Tapatalk

[Fastest1]

This is what the manufacturer says about pump orientation and location:



I am a big fan of draining above the water line. It's great to have that visual and audible indicator of when it's done draining. Plus it's fun when the kids are swimming on the side of the boat to fill a bag a little and then switch the drain on when they swim by the thru-hull and get them!

I only have 1 reversible on my boat, but I've done the following:
I have 3 different plastic ball valves in line. 1 is for a bag under the surfside bow seat, the 2nd is for a 400 bag that's under my surfside seats (gets used all the time) and the 3rd connects a coiled hose with a non-closing sprayer to the pump. I used it the other day to suck out water from the bilge that the bilge pump wasn't getting. I will also test it to see if I can use it to spray kids as a water gun of sorts. haha.

On my reversible, I have the 2 check valves so I can have the above water line draining as pictured in the diagram:
http://cdn.shopify.com/s/files/1/0106/9702/products/Automatic-Ballast-SystemPrinter1_grande.jpg?v=1397705571



As far as changing the way it fills or drains from the bag itself. My understanding is that the reversible pumps are powerful enough that head pressure really doesn't affect them much and in turn having them fill from the bottom should be fine. I wouldn't waste my resources there.

I have heard you can reprogram the timers, but I don't have timers, so I have no idea. I turn off my switches when water starts coming out the vent lines.

Do you have yours hooked up this way? I cant see how the pump pulls water in. Seems like it would pull air in from the above water vent. You have the discharge line connected after the vent check valve.

[jstenger]

You would have to add another check valve to the new discharge line. It would let water out and keep air from coming in.

[Fastest1]

Exactly what I was seeing.