What Size Bilge Pumps.

[marklo154]

I figure I would start the repairs to my boat with bilge pumps. I have a layout of the boat f-36 tricabin, shows 3 bilge pumps . I was just wondering
1) what size
2) should they all have automatic floats.
3) should they all be wired in series.


Thanks

[prowlersfish]

I figure I would start the repairs to my boat with bilge pumps. I have a layout of the boat f-36 tricabin, shows 3 bilge pumps . I was just wondering
1) what size
2) should they all have automatic floats.
3) should they all be wired in series.


Thanks

1) Depending on the room you have and the hose sizes , I would same 1500 gph would be a good choice , but bigger never hurts .

2) I would have them wired to a automatc float or use one that has a build in float.

3) wired in series ?? I am not sure I under stand the question . But the all pumps should have there own wiring . And all should not go to the same battery .

[Big D]

I figure I would start the repairs to my boat with bilge pumps. I have a layout of the boat f-36 tricabin, shows 3 bilge pumps . I was just wondering
1) what size
2) should they all have automatic floats.
3) should they all be wired in series.


Thanks

1) The size you can get away without changing anything will depend on what is there now, for example; the size of the discharge hose/hull fitting dictates the pump's discharge port size, and perhaps more important, DO NOT get a unit that draws more current than the existing wiring is designed to handle unless you are prepared to upgrade the wiring and the circuit protection.

2) I think each pump should be hooked up to its own float switch.

3) No, they do not get hooked up in series. They get hooked up in parallel; each one goes directly to a power source/battery or bus. Each unit should have it's own fuse or breaker, and as Paul said, do not hook all of them up to the same battery. To prevent accidental shut off, I do not like providing the ability to shut the circuit off through a switch unless it is a keyed switch. Do not use a bilge switch at the helm with an "OFF" position, I like "Auto" and "Manual" only.

While you're at it, put one of these pumps and switch, or just another switch on its own a little higher than the rest and hook it up to the ship's horn. This can serve as a high water alarm to get the attention of folks in the area should pumps fails or she takes on more water than the pumps can handle.

[prowlersfish]

Good point on # 1 I should have said something about the wiring .

[guglielmo6160]

when I install bilge pumps, here is what I do

1 I make it so no matter what happens I cant shut off at least one pump, which means no shut off switch at all, direct to at least one batt
2. more gallons per hour is always better
3. dont cheese out on quality, get the best one you can afford, and always,,,, always have a backup

[Big D]

....They get hooked up in parallel; each one goes directly to a power source/battery or bus.....

I should clarify that when I stated "battery" I used the word to explain a main uninterupted power source. You should not hook up any accessories directly to a battery. The only wiring in direct contact with battery terminals should be main battery cables. All else should be hooked up to a bus bar or if available, the appropriate side of a battery switch. In this case, a bilge pump would be hooked up to the source side so you can't inadvertently shut the pump circuit off. The less wiring at the battery the better. Battery terminal connections are also more likely to corrode than anywhere else, not something you want happening to wiring feeding a critical system.

[comodave]

The biggest ones you can get in there, taking into account the previous posts about wire size. Also, do not go cheap on the hose and use the corrugated plastic hose. Instead use smooth wall hose and use a quality hose at that. Using a smooth wall hose will cut down on flow resistance and result in more actual pumping capacity. The through hull fitting should be high enough so that it will always be above water, but putting it way too high will add head resistance. You need to check the ratings for the particular pump as to head height and hose size and type as well as voltage. Having a pump rated at 1500 gallons per hour and installed improperly could give you a pump that will actually perform at 600 to 700 GPH... I like to have wiring that equates to 3 per cent voltage drop instead of 10 per cent. Bilge pumps are as important as your electronics in regards to safety.

[Big D]

....I like to have wiring that equates to 3 per cent voltage drop instead of 10 per cent. Bilge pumps are as important as your electronics in regards to safety.

++1
Max 3% voltage drop for critical systems. This also helps keep the pump's pumping capacity at the level it's rate for.