Bilge Pump Float Switch- Should I follow These Instructions

Electrical & Electronics
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Wife just surprised me with a trip to Tavernier in the Spring. I plan to trailer down and do some fishing in the area.

The location we are staying comes with a boat slip. Up to this point, my skiff has never been slipped- and thus just has a manual Bilge Pump.

I am going to upgrade to a float switch and for kicks and giggles, I asked MSFT Copilot to create a wiring diagram.

If I follow these instructions exactly- how would I do?!?

Bilge float switch
Bilge float switch424Ă—316 17.5 KB

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Pretty close. The switch will have it’s own power supply with, I think, a 5a fuse. You might consider just replacing your pump with a pump/switch in one….

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Um… you don’t LOL the wiring looks wrong.

We have a How -To on our website this may be a better resource to help you wire up a float switch properly.

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Instead of re-inventing the wheel…. If you buy the standard Rule float switch it comes with a diagram showing how to rig it properly… I’m not a fan of pumps that have an internal float switch since most of them work by “sounding” - the switch activates every few minutes wherever you are (including while it’s sitting on your trailer), turning the pump on for a moment and continuing if it pumps water… That on and off is noticeable -particularly when you’re poling up shallow and trying to be quiet… Along with that float switch I’m always rigged with a three position switch for that circuit, set up ON, OFF, ON with one side activating the switch - the other ON position turns on the pump manually as needed… Hope this helps. Having a light on your dash that comes on whenever the pump is activated is a very good idea as well since switches stick occasionally and you really want to know if that pump is running when you’re on the water and underway… One more of those “ask me how I know” deals

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:index_pointing_up:

Same here!

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I’m assuming your making a joke of the labeling on the diagram right? Fused source to float then the pump and another fused source to switch to the pump. One line is incorrect as well. Must have gotten lost in translation to English.

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Didn’t see the 1st part about copilot sorry. That crap only gets the answers close enough to make it dangerous no matter what you ask it.

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If you just want to add weight to your boat, follow that diagram precisely. :rofl:

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if your skiff is not self bailing, I’d add a high water alarm…simple to do.

It will let out a scream once it covers the little box sensor.

I don’t have one, my skiff is self bailing and I rarely leave the boat int he water over night…but, I probably need to install one.

DC

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bit if a shameless plug… we carry a kit if you are interested.

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I am not a master electrician or vessel rigger- but I had to chuckle at what Co-Pilot came up with.
I was so appalled, I figured I would post… more or less for the humor to all and as a flash back to a Fora Frank type of answer.

I like the idea of a full rewire to the whole boat. Everything I use works fine right now- but the under console wiring looks like a bowl of spaghetti and causes me anxiety everytime i look under it.
I will probably do several upgrades - and will check out your sight @iMacattack

@Birdyshooter for the funniest of replies. It made me laugh out loud for real!

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I asked Capt GROK4 (the AI system I use) and here is what he came back with …

I bit more detail then Co-Pilot. Scary stuff…took about 1 1/2 minutes for the GROK-STER TO COME BACK WITH AN ANSWER :slight_smile:

To keep Grok’s boat (or any boat) from sinking, wiring a bilge pump with a float switch is essential for automatic water removal. I’ll focus on a reliable setup that includes a three-way panel switch (Auto/Off/Manual) for added safety—this allows automatic operation via the float switch, manual override if needed, and an off position. This is a common marine standard and helps prevent issues like a stuck float or dead battery drain. If you prefer a simpler automatic-only setup without the panel switch, let me know, but the enhanced version is recommended.

Key Components Needed

  • 12V DC bilge pump (e.g., Rule or similar brand; check amp draw, typically 3-5A for small pumps).
  • Float switch (e.g., Rule-A-Matic or equivalent; rated for at least the pump’s amps, up to 20A at 12V).
  • Three-way bilge panel switch (Auto/Off/Manual; often with an indicator light).
  • Inline fuse holder with fuse (size matched to pump: e.g., 5-10A slow-blow for a 3-5A pump; always slightly higher than the pump’s max draw but not exceeding wire/switch ratings).
  • Marine-grade wire (14-16 AWG tinned copper for corrosion resistance; red for positive, black for negative).
  • Waterproof butt connectors, heat-shrink tubing, and marine sealant.
  • Optional: LED indicator light (wired in parallel to show when the pump is running).

Wiring Steps

  1. Prepare the power source: Connect from the boat’s 12V battery or dedicated bilge circuit. Ensure all connections are above the highest possible water level to avoid shorts.
  2. Positive side wiring:
    • Run a red wire from the battery positive (+) terminal to the fuse holder. Install the appropriate fuse.
    • From the fuse holder, connect to the input terminal on the three-way panel switch (usually the center or common terminal).
    • From the panel switch:
      • “Auto” position output: Connect to the float switch input (brown or positive wire on most floats).
      • “Manual” position output: Connect directly to the bilge pump’s positive (+) terminal (brown wire on most pumps).
    • From the float switch output: Connect to the bilge pump’s positive (+) terminal.
  3. Negative side wiring:
    • Run a black wire from the battery negative (-) terminal directly to the bilge pump’s negative (-) terminal (black wire).
    • If your float switch has a ground wire (some have three wires), connect it to the negative bus or battery negative.
  4. Optional indicator light: Wire it in parallel between the pump’s positive and negative terminals—it will illuminate when the pump runs, even in auto mode.
  5. Secure and test: Use heat-shrink connectors for all splices, seal with marine-grade adhesive-lined tubing. Test the system: In “Auto,” raise the float to activate the pump; in “Manual,” it should run immediately; in “Off,” nothing happens.

Fuse and Safety Notes

  • Fuse size: Match the pump’s amperage rating (e.g., if the pump draws 4A max, use a 5-7.5A fuse). This protects against overloads or shorts. Never skip the fuse—it prevents fires or damage.
  • Wire gauge: Use at least 16 AWG for runs under 20 ft; go to 14 AWG or thicker for longer runs to minimize voltage drop.
  • Mounting: Place the float switch 1/4" above the pump base on a flat surface. Angle limits: Up to 30° forward, 5° aft. Clean debris periodically.
  • Always follow ABYC (American Boat and Yacht Council) standards for marine wiring to ensure safety and compliance.

Here’s a clear wiring diagram for this setup:

image
image450Ă—274 1.92 KB

If your pump or switch has different wire colors (e.g., some floats have black/brown/white), consult the manufacturer’s manual. Double-check polarity to avoid damage. If you need a custom variation or help troubleshooting, provide more details!

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CAPT,

Looks like an easy system to install…I’ll put in an order next week…do I get the Skiff Forum Friends and Family Discount? Thanks

dc

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That looks pretty good. Wordy but clear. Just don’t tell anyone I said that.

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I have 2 pumps in my CS. The first is a switched pump, switch on the console along with everything else. The second pump is a float activated/switched pump. The float side is hot wired direct to the battery, no switch. It is fused. The switched side is on a separate switch from the first pump.
The reason I wired everything in this way is because factory had a livewell pump with a pickup on the bottom of the transom. The pickup is still there, I’ve got it capped off. The first pump I described can be hooked up and run as a livewell pump if I ever decide I need it…which is not likely.

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@lemaymiami Hey, saw your comment about “sounding.” My Rule pump does that, and I thought it was debris or something triggering the switch and it was making me crazy. This is the first I’ve heard of it, so thank you. It seems like it does it only when I’m actively fishing. I don’t think it does it at the dock. Is it just a timer, or does something else trigger it? Maybe I don’t hang out enough at the dock to hear it.

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I’m far from an electrician/ wiring guru. I just know how mine works. Take it for what it is worth. I have a switch for manual activation and it only works when the pergola switch is on. It is also wired direct to battery with fuse that will always activate the float switch whether the battery is on or off.

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The two most troublesome things in boating: Trailer lights and bilge pump switches. Wire your trailer with tinned marine wire, solder all connections, coat with liquid 'lectric tape and shrink tubing. Don’t use the trailer frame for a ground. Run a separate ground wire from all lights all the way to the plug at the front. The other problem: Install a Water Witch sensor. No moving parts. Once a year, clean the bilge scum/oil off the two metal contacts. Once I did that for the two pumps on my trawler, I never had another problem. Wire it in just like the stupid mercury switches. I looked at the price, and they’re just about what I paid in the '90’s. TJ

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