quick question about 750s in '01 SAN (draining through current rubrail fitting?)

[bsnively]

I was going to swap out the hard tanks in my '01 SAN, and put in the 750's.

I would really like to get rid of the need to constantly open and close the valve in the engine bay area as well. I know by switching to jabsco pumps, this can be achieved, but was thinking of doing a different short term solution -- if it would work well.

I was thinking that I would put in a check valve on the current fill/drain hose -- and make that a dedicated fill line that get plumbed to the 750's (eventually making it use two pumps, but for now -- use the single pump to fill both bags).

each bag would then have a dedicated pump on it that went out the current vent hole. I like this because it gives a nice indication of when the bags are empty (since the sensors won't work on the dash/etc).

My question is if I need a dedicated overfill/vent plumbing in addition to the drain plumbing. The drain pump will be attached to the bottom of the bag -- and I was assuming that if the bag was full -- the water would be pushed through the drain pump and out the current vent hole. This would make the install much simpler rather than putting a T on the on the current through-hull fitting near the rub rail and having to install more check valves.

Will that work well -- or do you think I need to add the extra pieces/etc?

Thanks,
Ben

[crobi2]

Yes, that's exactly what happens. I use 2 jabsco's to fill my rear sacs and each sac has a Attwood 800 screwed into the fitting on the back for a drain. Now I also chickened out and drilled new rub rail thru hulls for vents too.

If you need to save money at first and split one jabsco between the 2 sacs, you can probably get away with just venting through the drain pumps. Later, when you want to add the second jabsco, you can think about adding more vents. Using a vent also helps purge air from the sacs. I put the drains for all of my sacs along the rub rail just in front of the driver like the 2003-2004 models and kept the rear vents as vents. I also got a smoking deal on stainless thru hulls and replaced all the cheap plastic ones with those.

I would just go straight to the jabsco and forget about one way valves, etc..

The reson I like the system so much is that I can just turn on my fill pumps (I also have a 600# locker sac and a 400#ish integrated bow sac that are filled by a rule 2000 gph pump that is controlled with valves in the ski locker) and just let them go until water is pouring out the vents and drains and not have to worry about blowing out a sac.

Also when it comes time to drain, I just hit the switches and forget about it till later (because the aerator drain pumps can run dry without injury). Also my jabscos never have to reverse and flip over the impeller vanes. I even have a scoop on the bottom and the jabscos still act as a check valve.

Couldn't be happier with the system.



Edit:spelling

[crobi2]

BTW: if you are going with the 750's in back you are gonna need about a 600# locker sac, and something up in the nose ( I use the fly high integrated bow sac - figure it can hold about 400# under the front seats) to balance the boat out. You will also want a new prop. I could get on plane with the orig. OJ 14x18 ( the GT40 gots beau coup torque!) but it would take a while, and probably wasn't real good for the engine.

[bsnively]

Great info -- thanks!

Where did you end up mounting the jabsco pumps -- have any pics?

Thanks
Ben

[crobi2]

I think the best place for the pumps on our year models of boat it right behind the rear seat back at the front of the locker with the motor up and the pump/fittings on the bottom, shoved up as high as it will go without touching the top of the deck and then drilling 4 holes and using bolts to hold it on. When you put the rear seatback on again, it covers up the screw heads.

I don't have any pictures. There was a thread where a guy picked that spot and put pictures, you may try to search for it. That's where I got the idea from. He actually managed to fit three pumps under there by staggering two of them so the hoses would clear. I only have two jabscos, one at the front of the right locker and one in front of the left. Works great.

When you actually get more pumps, I would drill an intake thru-hull for each one. I split a 1.5" between the two pumps and it works fine, but I think the consensus now is one thru-hull per pump.

[bsnively]

great -- I'll do some more searching. There has been some great ballast threads I found so far. I didn't recall seeing that yet....though likely user error ...I'll do some searching.

Thanks,
Ben