Bilge constantly filling with water

[MakoMike76]

Hi everybody!

I just bought my first boat, a '76 Mako 17. I love it, but i don't have a lift so I have it docked in the canal behind my house, and every couple of hours it has an inch or two of water in the bilge. It had a bilge pump, but no auto switch, so I installed one yesterday and it works, but it was a cheap one and doesn't work very well. When I came home from work today there was probably about three inches of water in the bilge and the switch was up, but must not have engaged. As soon as I touched it, it turned on, but obviously I have a problem! Other than getting a better auto switch, does anyone have any ideas for a fix, or where it may be leaking? There is no obvious water flow when looking in to the bilge. It hasn't rained at all since I've had it on the water. I haven't used the livewell and none of the storage bins have had any liquid in them. I put the three plugs in the transom before putting it in the water. There is a round black plastic thing on the transom below the motor that the seller said he thought was a scupper or something but that it never worked? I'm at a loss! The last thing in The world I want is to come home and see my awesome new boat sitting on the bottom of the canal. I won't have the time to haul it out onto the trailer until the weekend, so I'm just looking for any and all possible help. Thanks so much!!

[1977Mako22]

Probably getting in around a thru hull fitting or something like that. Could be old water in the hull from a previous rain. May want to park it on a steep incline to let her drain out and see if the water is coming up from around the center part of the boat where the hull is deeper. Its really hard to guess without being there or pictures. Good luck.

[Sailor]

that's a lot of water in a short amount of time. Get the bilge as dry as possible and stick your head in there with a flash light. You will find the source. I would also consider adding a secondary bilge pump and most importantly a battery charger so that you dont' have a dead battery and boat underwater.

This is an issue you need to take care of now.

[Matt221]

ditto what Sailor said. put your head in the bilge with a flashlight. that's how i found my leak, which was coming through one of the engine bolt holes. regardless, you should be able to find it.

[powerplay1]

Keep a keen eye on your through hulls and drain pipes. In my recent experience, they are made out of plastic and mine were VERY brittle after 26 years (one actually broke in my hands). If one of yours has even a hairline crack, that could be your problem.

The other place to look is around your drain plug. In my old 20' Mako, the bronze sleeve actually disintegrated and was leaking... The plug looked like it was in, but in fact it was leaking enough to fill the bilge every 30 minutes or so.

Good Luck! Its always an adventure!

[302Harbour]

Ditto on the brass fittings. The scuppers on my 22M had a separation between them and the fiberglass. I would keep it in my slip over the weekend and could never figure out how water was getting in. Took forever but finally figured it out.

Keep it in the water, wait for dark, break out the flashlight, stick your head in the bilge as best you can, you will find it.

[dayjtradr]

MakoMike, I have a '77 17' with an old 90 that weighs just over 300 lbs and the batteries in the console. There is a factory deck hatch to access the bilge at the rear of the boat and just ahead of the scupper gutter. That hatch has a factory hole, I guess for lifting, facing the scupper gutter. If there is any water coming in the scuppers when at rest that fills the gutter, it could find it's way into the bilge through that hole or even around the hatch. Just a thought.

[Triplecrownnc]

The best way to find a leak like this is to put the boat on the trailer, dry out the bilge, go as far as toweling it out. Get a bright light and have a friend back the boat down the ramp so that the transom is well into the water, use your light to look for the leak. Sometimes you have to pull out and repeat until you can pinpoint it.

A leak like this can go from a few inches an hour to a sunk boat if the leak is in a failing fitting. Don't wait.

[MakoMike76]

Wow! Thanks soo much guys!! You guys are awesome! I posted the same question on thehulltruth and got a bunch of old salty seamen telling me I'm an idiot for not immediately pulling the boat out. I got a hold of the previous owner and he said he had it in the water for days at a time without a leak, but he replaced the brass sleeve of the bottom transom plug recently and hadn't put the boat back in the water since. He said he would bet that was the problem. I have a mechanic coming out tomorrow to check it out, and he said he could haul it, or put in a better bilge pump to get me through til Friday when I can haul it and bring it to him to save some money. I really appreciate the feedback and help and will stick to this REAL community forum from now on! Thanks again guys!