Bilge pump check valve

[Maine Sail]

Tom,

I like this idea, since I have been exploring the idea of installing a washdown pump also.

The obvious drawback I see at a glance, unless I am missing something, is that a $200 washdown pump will pump only about 300 gal/hr., while a $200 submersible bilge pump will pump 10 times that much. Not really familiar with them, it seems to me that maybe a lot of the washdown pump's mission is to develop pressure, not so much pump volume. ??

If you go down this road, please update us on what you are learning/doing. I am intrigued.

Dean

Dean,

Please don't ever take a centrifugal pump at face value! Even with a Rule 2000 you'll be very lucky to move even a 20% of that rated volume from the very low sump of a CD.. The diaphragm pumps can move just about their rating so a Rule 2000 is a lot closer to a 300 GPH centrifugal pump performance wise than boaters often assume..

[Carl Thunberg]

Tom,

Somehow, this idea just strikes me as being unsanitary. I know no one drinks from a washdown pump, but people do sit or lie down on the deck afterward. Bilge water can be pretty nasty stuff, and even with a Y-valve, there's going to be some residual bilge water inside the diaphragm pump. I'm not sure I'd want to spray that on my deck. I'd be curious to see if ABYC has weighed in on this.

[Dean Abramson]

Carl,

I think that I am going to use Tom's idea. The idea, from my point of view, is to have this washdown pump be an emergency/backup bilge pump. Hopefully, it would live its whole life serving only as a washdown pump.

I will retain the centrifugal pump in the bilge for my main pump. My wife tells me I am wrong, and that that there is no check valve; the float switch and pump are on a platform with lead feet; this is high enough that it keeps the flowback from tripping the switch, hence no cycling.

Mine will be plumbed with 2 Y-valves. One near the intake seacock (which currently is the head flush intake), which will send water to either the head or to the washdown pump. The second one near the pump, to choose between the bilge hose or the seacock hose.

I will make the bilge hose come to about 8" above the bottom of the bilge, so hopefully even when used as a bilge pump, the worst (solid) dreck would be left behind.

For bilge pump use, I will have a length of hose, with no nozzle, to route the bilge water off of the deck and overboard. But even if you had no time to fool with that hose, I don't think there would be much harm in letting the outflow run down the deck to the scuppers.

Am I missing something here? I am looking at the Johnson 5.2 GPM pump complete kit.

Hey Carl, you want to help me install it? That might give you more confidence in it... ;-)

Dean

[Carl Thunberg]

Perhaps my queeziness is more a reflection of the fact that I bought a neglected boat with a bilge that hadn't been cleaned in a decade, and the bilge odor had permeated the boat. I never did quite get the smell out. I'm sure your bilge is much cleaner. My reaction is more of a reflection of my own experiences.

[Jim Lewis]

Not sure about the 33, but on 30s the thru hull will syphon the sea back into the bilge when the left rail is heeled and sea condition such....and thru hull on port side......sailing more level or on other tack stops it.....but an hourly bilge check is not enough - if you are having a great sail heeling on the side of thru hull.....check bilge often......the manual fresh water bilge pump for the 30 is next to wheel....so just pump now and then to determine ......along with the appropriate visual checks.....sailing the same boat for a lot of years you get to experience it all.....last year sailing great, but electric bilge hose broke and was pumping water back into boat, and the fresh water pump failed too.....so water coming into boat thru thru hull fitting and bilge working and pumping back into boat...and manual pump not working.....changed point of sail pumped with portable hand pump.......tapped in wooden plug externally into thru hull.....and headed back to shore.....to old and fat to slide thru the cockpit locker in wind and sea conditions....unless manditory....LOL is a struggle to get back out of there when do it in the slip......

[Steve Laume]

Isn't this syphoning problem only related to automatic bilge pumps?

Up until last year, Raven only had a hand diaphragm pump with a high loop. I never experienced any syphoning problems.

Last year I installed an electric bilge pump with a through hull on the starboard side. This also has a high loop but no check valve or vented loop. It also has no automatic switch so only operates when I want it to. It was installed mainly as an emergency pump to help stem the flow while I worked on fixing the problem if one ever occurred.

As long as the through hull is not submerged when the pump cycles off it does not create a problem.

I usually use the hand pump as it has a strum box in the bottom of the bilge and lets me know exactly how much water I am pumping.

If you were turn off the automatic feature whenever you were sailing I don't believe siphoning would be an issue, Steve.