Raw water intake for ballast

(drknute3) · (drknute3) **Join Date: Sep 2008** 04-11-2009, 4:16 PM

So I am considering not drilling a big hole for intake. I am going to use the raw water intake instead. How many of you do this? My understanding is that there shouldn't be any effect on cooling right? Are you guys also pumping out through the same intake? If the motor is running and you are trying to empty, does the water from the ballast pumps (Jabsco) just get pulled into the engine cooling system? If I choose to empty back through the intake, how different is the sound of the Jabsco when it is no longer pumping water (ballast empty)? I am considering doing this as well to save me from having to run another T and hose to empty out the vents.

Thanks
Bill

(trace) · (trace) **Join Date: Feb 2002** 04-11-2009, 6:17 PM

I've done it on 3 different boats that I used for at least a couple years each, and never had a problem. That being said, I prefer a dedicated intake for more capacity and consistency.

(drknute3) · (drknute3) **Join Date: Sep 2008** 04-11-2009, 8:59 PM

How much capacity is lost by using the raw intake vs. a dedicated intake?

(nick_in_ssp) · (nick_in_ssp) **Join Date: Aug 2006** 04-11-2009, 9:42 PM

I agree with Trace, just drill the hole and get it over with. I have checked your work Trace and did many things similar.

(trace) · (trace) **Join Date: Feb 2002** 04-12-2009, 7:26 AM

It depends a lot on the design of your system, but I will say that the engine impeller pulls about 60 gpm (at max engine rpm), and the most I ever ran off of the raw water line was two Simers in parallel, which pull about 20 gpm. I wouldn't go more than that. 80 gpm is a lot for 1.25" plumbing.

(wakemikey) · (wakemikey) **Join Date: Mar 2008** 04-12-2009, 7:54 AM

Sure if you are driving around at speed and trying to fill it will be slower. When I fill I'm just sitting or driving slowly. When motor is off obviously there isn't any loss. When you are draining you can drive any speed. I just have one Simer on my raw water intake and it's worked fine for one year.

In the future if I expand to a second pump I may drill a dedicated through hull. But then again I don't have overflows yet either. My boat is older and my ballast system is more budget.

(drknute3) · (drknute3) **Join Date: Sep 2008** 04-12-2009, 7:59 AM

I am using 2 Jabsco pumps

(trace) · (trace) **Join Date: Feb 2002** 04-12-2009, 8:31 AM

To address your other questions, I would go ahead and put in vents too if I were you. Jabscos & Simers are much higher pressure than aerators (40 psi vs 5 psi), and can burst bags much easier than aerators. You have to watch them when draining too because you don't want to run impeller pumps dry.

(sbt3) · (sbt3) **Join Date: Jun 2002** 04-12-2009, 8:43 AM

I've plumbed many simers into the raw water intake and never had any issues. I have 3 running off the intake of my current boat with no problems.....

With that being said I tried to use ballast puppies last year on a install I did on a Malibu and for some reason they allow air through and the boat impeller lost it's prime somehow and ended up overheating the motor. Not bad but it got a little hot, I caught it before the alarm went off. I ended up changing these to their own hole. I'm not sure why, I can't explain it, maybe the jabscos are different than the simers somehow. I'd use your own hole with the Jabscos if I were you.

(trace) · (trace) **Join Date: Feb 2002** 04-12-2009, 4:35 PM

Interesting! This is the first problem I've ever heard of with using the raw water intake.