salt water leak

[el jefe]

I have a salt water leak somewhere in my boat. I know its salt water and not fresh by taste. I have been monitoring it for a while. I am trying to figure out the most logical method to work in trying to eliminate the leak. There are 5 sea cocks on the boat. Four in the stern for the generator, ac, saltwater washdown and bait well. The fifth is for the holding tank (its a freshwater head). There are the through hull drains and there are the transducer (stern) holes. The water is clean if that means anything. Any suggestions on going about trying to find the source. thanks.

 

[bc282]

how much water are we talking here?
age and boat model?

 

[el jefe]

2005 Marlin. enough to need to turn on forward bilge. when that hits suction level, then hand sponge out from bow area where water sits about 7 gallons. I am having trouble getting a constant because I just filled tanks and I just replaced salt water wash down pump.

 

[seasick]

2005 Marlin. enough to need to turn on forward bilge. when that hits suction level, then hand sponge out from bow area where water sits about 7 gallons. I am having trouble getting a constant because I just filled tanks and I just replaced salt water wash down pump.

Is the aft bilge filing up too or just foward bilge?
Does iy happen when sitting or when moving?
Anchor locker hatches are common area for water, so are leaks in deck to hull seal. These are issues when under way.
By the way, if its rain water, it will probably still taste salty from residue in the bilge. You need to taste it and then taste real sea water in your are to compare. YUK!

So as mentioned, first things to watch are when does it get water ( moving, docked, raining etc) and go from there.

 

[seasick]

2005 Marlin. enough to need to turn on forward bilge. when that hits suction level, then hand sponge out from bow area where water sits about 7 gallons. I am having trouble getting a constant because I just filled tanks and I just replaced salt water wash down pump.

Is the aft bilge filing up too or just foward bilge?
Does iy happen when sitting or when moving?
Anchor locker hatches are common area for water, so are leaks in deck to hull seal. These are issues when under way.
By the way, if its rain water, it will probably still taste salty from residue in the bilge. You need to taste it and then taste real sea water in your are to compare. YUK!

So as mentioned, first things to watch are when does it get water ( moving, docked, raining etc), is there water forward and aft and go from there.

 

[el jefe]

Seasick, all good questions and I can answer most.
Is the aft bilge filling up. No, but there is some water there, where most times it was dry. That makes me think the leak is aft. I also think that because I just checked the forwarded sea cock for the holding tank and it is completely dry.
I keep my boat behind my house so I have been able to monitor the situation. As I have not gone out this week, I can pretty much rule out the water coming in through the anchor locker, deck to hull seal.
Is it rainwater. It did not rain this week in my area of So. Fla. I am sure its not fresh because in the past I have gotten water in the bilge from heavy rain or wash down and there is a different taste. Also, the water is very clean, meaning to me that it is a current leak below the water line.

 

[seasick]

This is going to be a pain to isolate but if you can close all the sea cocks, drain out the water and let her sit again to see if you get water. If not, it's a plumbing issue ( of course that assumes the sea cocks themselves are not leaking. You would then open one at a time with time in between to see if water accumulates.
If it still leaks, we need to look at hull fittings but probably only below the waterline ones. If you didn't have the leak before replacing the wash-down pump that work may have disturbed something that was marginal. Sorry I can't be of more help.

 

[megabytes]

Do you run your livewell? Do you keep all seacocks closed when not in use?

 

[BobP]

Let the FW water tank run dry, and see if anything changes.

Can't hurt, no cost to do.

 

[el jefe]

Mega, I keep all sea cocks closed when at dock at underway unless using system. Last use was generator and ac last weekend. I ran the livewell (which I never use) about 4 weeks ago and filled up just to see if working. Since then, however, my boat has been out for service and bilge emptied so I don't think its the livewell system.
BobP. good suggestion. will do tonight.
Am going to check bilge tonight which will be about 36 hours. Checked this a.m. and there was less water than had accumulated in the previous 24 hours.
As I work through this, I am leaning toward's possibility of a) generator b) ac system. If leak is from seacock to outer hull (and it is not total breach how does that happen). If it is in seacock to generator or ac ( which I kind of doubt) then I would have to have them running for extended periods to produce this much water.

 

[BobP]

A/C SW pump & filter is below water line, so inlet and outlet hoses are too.

Should keep sea cock closed when not in use.

 

[BobP]

You have a bow thruster on the Marlin?

 

[el jefe]

Ok, here is an update. I am providing these reports for a) the useful comments along the way and b) in case someone else encounters a similar problem.
First, yes I have a bow thruster but that area has been and continues to be bone dry.
Checked forward bilge this a.m. and p.m. and took about two gallons in the a.m. and about 2 quarts in the p.m. I dried out the forward bilge and am going to let it sit again tonight. I checked afte bilge and it is dry. This leads me to believe a) water has pretty much moved forward to forward bilge b) that leak is from a prior event and probably not from sea cock to outer hull. Looking back, as I said I ran the ac and generator about two weekends ago and inadvertently left ac sea cock open. It is my SOP to have all sea cocks closed when systems are not in use but I forgot to close ac. So tomorrow a.m. I am going to do first big test. I am going to run ac for an extended period. I expect to see condensing water in sump that should be fresh and handled by that pump. If the leak is in the ac from the salt water that pumps in to cool then it would seem that leak is in a hose somewhere. Of course, if my bilge remains dry then I have ruled out ac and will move on to generator.

 

[el jefe]

Another update. After testing and searching I finally found that a flashlight was my best friend. I was looking at the inside of the transom and saw a water reflection. I dried it off with a pole wrapped with a towel and let it sit for a couple of hours. Sure enough the water was there. The leak was coming from the two transducer holes in the stern. I pulled the boat out, took of the metal covers on the outside, pulled out everything that was in there (4200) and refilled the hole with pool putty both inside and out. I had a small skinny guy go in through the hatch (this a 2005 so the hatch does not fold out allowing access) and fill in the transducer holes from the inside. It has been dry since then. Next time one of those transducers craps out I am going to switch over to thru hulls.

 

[BobP]

Who would have thought ducers?
That was a lot of water coming in.
It was not installed correctly.

The only other thing I was lower engine(s) mount bolt holes.