Bilge pump questions

[TCinVA]

Hi people,
I have a 1984 Grady White 20' Overnighter that I am in the final stages of rigging with my motor and accessories, and checking/fixing small problems. My question is, what size bilge pump should I use? I have always owned Boston Whalers previous to this boat and never worried about one. Is one with a float switch built in reliable, or should there be a separate float switch for some reason? I was looking at a Rule 500 or 800 automatic. My boat lives mostly on a trailer, once a year on a pier at a rental cottage. Thank you in advance! :<><

 

[G8RDave]

The biggest one you can fit.

 

[seasick]

Current models in that size use an 1100 gph pump and as mentioned, bigger is better ( to a point).
I would avoid the electronic automatic pumps that test for the presence of water every two minutes or so. Those pumps tend to run down batteries. I have a separate float switch on my pump and since the mounting holes are already there, I would replace with the same two components, pump and float switch.
Good luck with your project

 

[DogBone]

I rigged 2 Rule 1100 GPH bilge pumps in my rig. I mounted the second one about 2 inches higher than the one in the lowest part of the bilge. The second one serves as a back-up in case the first one fails or can't keep up. Both of mine have separate float switches mounted at the levels of the pumps. When it comes to safety systems, I like to have redundancy where I can.

 

[seasick]

I rigged 2 Rule 1100 GPH bilge pumps in my rig. I mounted the second one about 2 inches higher than the one in the lowest part of the bilge. The second one serves as a back-up in case the first one fails or can't keep up. Both of mine have separate float switches mounted at the levels of the pumps. When it comes to safety systems, I like to have redundancy where I can.

Should your hull be compromised by lets say a 2 inch hole a foot below the water line, 4600 gallons per hour will flow into the bilge. One pump, two pumps, it isn't going to mater really.

 

[DogBone]

The second pump does serve as a back up should the first one fail. I had this happen on a boat before,
why I installed two. Obviously there can be conditions that no pump could overcome, but better to have back up and extra capacity to give you more time to get to safety or make a repair, if possible.

 

[Grog]

The pumps should be mounted as low as possible, you can mount 1 switch higher than the other.

When I bought a new bilge pump I went with the biggest pump with the same size hose (2000).

 

[TCinVA]

Thanks for the advise. Is using 2 a common thing or just for hardcore offshore types?

 

[TCinVA]

I mean, advice!

 

[DogBone]

I don't know how common it is to have two. I had one fail, so I like to have back-up. I think I've seen having two mentioned in BoatUS magazine. If you think about it they sit in dirty bilge water most of the time (they can't pump the last bit out), they could jam from debris or just fail from corrosion. That is why I mount the second one higher. If the first one does it's job, the second one shouldn't ever get wet, leaving it in the best possible condition should it be needed. If you are going with one, get the biggest one for the size thru-hull you have.

By the way seasick's calculation for a 2" hole a foot below the water line was spot on at 4600 GPH. He must be familiar with a man named Bernoulli. Your pump or pumps aren't going to prevent you from sinking should you hit something and tear a big hole in your hull, but you do want them to keep you afloat or give you more time should you have a more common failure such as a lost drain plug or a leaking thru-hull. If a drain plug is 3/4" in diameter (I think) then at a foot below the water flow rate would be approximately 650 GPH, at two feet it would be approximately 915 GPH, just to give you a feel for what you are up against. Seasick you want to check my numbers, I just scaled them from your number for area and depth using Flow=Area*sqrt(2gh).

 

[RussGW270]

Ok, pump is not working. Trying to figure how to get it out

 

[Bloodweiser]

Russ start a new thread. It should unscrew though

 

[RussGW270]

New bilge pump installed, except for the breaker. Storm rolled in just as I was finishing up.

The original float was not attached to the hull, not sure what good that did. The screws lined up, but not in the direction needed for the new pump.. heh, but I was able to get it in. I find it funny the pump and the float came with ZERO screws... silly to me.. if you have to replace one, you'd assume the old ones were useless, which 2 were. No biggie... replaced them all with stainless screws.

All in all, easy, except out of reach and there was like only 3" of wire left where they spliced the original pumps in... another dumb move. I was able to wrap them and get it connected, but when I rewire.. going to make sure the splice happens well before that.. or, in fact.. quick connects should be used. I did not have room to add those, but plan to add them on any new wiring.

I think, soon, I want to replace those two valves down there.

R

 

[RussGW270]

Question about the pump....

I tested it last night and it works like a champ... but I must have a wire crossed. The pump works automatically just fine with the float, but the manual switching does not kick it on. Going to look closer today, but waiting for a window of work slowing down heh. The light on the switch works, but the pump itself does not turn on manually, so....not sure.. may not have connected the wires back to the switch correctly is all. The storm kicked up just as I was closing it up so no time last night.

Either way, not really a show stopper, but hoping it is a quick fix and, debating best way to test it without having to cut the wires. They left almost zero room to reconnect a new pump.. go figure. The light on the switch comes on.. heh.. so something is getting power

R

 

[seasick]

Assuming your pump has two wires, the feed from the manual switch connects to the hot side of the pump and not switched by the float. If you have it wired correctly and it doesn't work, then you are not getting 12 volta at the wire from the switch. Both manual and automatic share the same ground so that circuit is OK.

If you want to see if you wired the manual function through the float switch instead of bypassing it do the following:
Remove the fuse near the battery for the auto bilge function. Trip the float, the pump should not run.
With the fuse still out,
turn on the switch at the helm.
Trip the float. The pump should not run. If it does you wired the manual feed incorrectly

 

[RussGW270]

Yea, probably swapped the two gray wires...hence why it runs. If that is the case, I can clip it halfway and swap the wires. I literally had like less than 2" of wire left after removing the old pump etc. When the new wires go in, next year or the year after...heh.. I will ask for stuff like the pumps to have some sort of disconnect so more "plug and play".

Thanks Sea

R

 

[RussGW270]

Welp, now no pump at all again. Should have left the stupid thing as is.

Taking the freaking day off to figure this flippin pump out again.

I swear, this boat is f3747 cursed.

R

 

[seasick]

Get the manual pump working first. Don't connect the float switch. Make sure you know which of the two feed wires is the juice from the helm switch. The other wire is the ground
Also identify and label the auto function feed.

Once the manual function works, you will connect the auto feed wire that you labeled to one wire of the float switch and the other wire of the float switch to the same connection you made earlier for the manual feed (12v wire)

You mis-wired something. Also add a length of wire to that 2" short wire, crimp a but connector. leave some wire coiled aft for the next time.
Do not crimp the hot wire for the manual function since you will need to add a third wire later for the auto feed. Twist the wires for now, crimp when everything is working.

 

[RussGW270]

We figured it out. They had the original wired wrong. It worked when I first hooked it up but blew the main aft pump breaker, which I now need to replace.

We ran it to the “Memory” breaker, both 10 amp, and tested all wires and now it is correct.

Was not wired correctly to begin with.

Will order extra breakers later today.

R

 

[RussGW270]

Okay, we were buttoning her up. Here is what we did/found:

When I went to hook up the new pump and float, I noticed the old float was not secured to the bilge. I went crazy trying to locate the screw holes to put it in the same place. So, not finding any, I just bought stainless ones and added my own.

For the wiring, I took pictures of the previous wires and kept the colors marked.

Turns out, the old float would never have been able to run as they had it wired wrong. When we took the main power panel off the transom, we cleaned and tested every wire (and re-routed the lower cross-over wire as it was rubbing the 4amp fuse). Then tested it all and found the aft pump breaker was dead and the float was connected to the wrong wires.

So, we ran the correct wires and now the float works with power on or off and the console switch works only when power is turned on.

I need a new 10amp though

R