1998 - 19'-6" Osprey Leak -- Please Help Troubleshoot

[themadpiper]

Hello Guys,

I've visited the site from time to time and always appreciated the knowledge here and willingness many have to lend a helping hand.  This time I've come here to ask for a some insight on a leak I've got on my 1989 19'-6" Osprey.  By no means am I an expert on boats.  I have just your basic knowledge coupled with lessons learned from a lot of time spend on the water.  Any help will be appreciated so thanks in advance if you can help me out.
 
A little bit on the boat....she was restored by the original owner in 2001 and was fully re-done from the stringers up and nida-core deck.  She's a fishing boat and her layout is very basic.  Livewell pick-up and drain, and the hull drain plug are the only points below the water line that penetrate the hull.  
 
The leak?  Well when the boat is sitting in the water there is no leak.  No issues at all.  When running even a short distance (2-3) miles, a gallon of water or so will work its way into the hull where it can be easily bilged.  Obviously the longer you run, more water.  Here is a list of things I've done to troubleshoot so far:
 
1. Valved off all plumbing and filled the livewell with water under standing "head pressure".  I did find a few leaks from the livewell and sealed those off.  Also found a few drips from various plumbing connections and sealed those off.
2. Filled the hull with approximately 8"-9" of water insuring all objects typically below the water line would be under water from inside.  I looked for leaks externally and found one minor drip at the livewell pick up that was repaired. No other leaks from the hull were observed.  I repeated this process a few times and each time got the same results.
3. Inspected and tested all plumbing, pumps, hoses, etc. and found no leaks.
4. Resealed the cap seal at the stern as some minor voids were noticed (very minor items).
5. I've run the boat every which way while observing below the deck and can't visually see water coming in anywhere
 
While going through this procees I did eliminate several small source leaks however the big issue is still there.
 
The only other areas I can think that have the potential to let water in are as follows:
 
1. Scupper drains (don't know how to test and determine if they're leaking into the hull)
2. Trim tabs?
3. Rub rail and cap seal (inspected and looks OK, however voids in the cap seal were noticed with the rub rail taken off)
4. Transom bolts (transom itself is soild)
 
A hull crack could be the culprit (hope not), but I think I would have seen that when the hull was filled up with water.
 
Again, any insight will be greatly appreciated.  Thank you in advance!
 
Nick



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[pete]

could the bilge pump outlet getting water in it as the boat is running?there needs to be a loop in the hose so water cant get in,just a thought.and welcome!

[John Jones]

2. Filled the hull with approximately 8"-9" of water insuring all objects typically below the water line would be under water from inside.  I looked for leaks externally and found one minor drip at the livewell pick up that was repaired.

Don't forget that the livewell supply line is under quite a bit of pressure when running if you have a thru-hull clamshell type pickup.  Much different than putting a little water in the hull.  It takes almost 28" of water to equal 1 psi at the bottom of the hull.  Anything higher than the bottom of the hull has proportionately less pressure to force through a leak.  9" is only 1/4 psi at the bottom of the hull.

Do you have small friend you can stand on his head in the bilge while you are running so he can look for a leak?  ;)

[flounderpounder225]

This is just something to look at, a friend of mine had a similar situation, months of him trying to find the leak, turned out that when the trim tabs were installed the installers did not use any or proper sealer around the ram mounts that attached to the transom, water constantly coming in.  probably not your problem, but nothing should be overlooked, run it and get down in the hull while running and look for the water, you will find it eventually.
Marc

[themadpiper]

could the bilge pump outlet getting water in it as the boat is running?there needs to be a loop in the hose so water cant get in,just a thought.and welcome!

I've thought about that one.  I have 2 bilge pumps and the discharge for each is well above the water line (a few inches below the rub rail).  It's certainly something else I can look at and will, making sure the discharge lines are looped as you suggest.  I can see how when anchored up and taking a beating, water could get in thru the bilge lines.  Thanks for the suggestion.

2. Filled the hull with approximately 8"-9" of water insuring all objects typically below the water line would be under water from inside. I looked for leaks externally and found one minor drip at the livewell pick up that was repaired.

Don't forget that the livewell supply line is under quite a bit of pressure when running if you have a thru-hull clamshell type pickup. Much different than putting a little water in the hull. It takes almost 28" of water to equal 1 psi at the bottom of the hull. Anything higher than the bottom of the hull has proportionately less pressure to force through a leak. 9" is only 1/4 psi at the bottom of the hull.

Do you have small friend you can stand on his head in the bilge while you are running so he can look for a leak? ;)

That small friend would be yours truly.  I've spent more time than I care to remember with my head stuck down there while the boat is underway and can't see water coming in from anywhere.  The livewell pick up is on the bottom of the boat and is a brass, strainer type.  I've disassembled it and put it back together once and it appears to be pretty soild.  Then again it's hard to duplicate the pressure as you've stated.

This is just something to look at, a friend of mine had a similar situation, months of him trying to find the leak, turned out that when the trim tabs were installed the installers did not use any or proper sealer around the ram mounts that attached to the transom, water constantly coming in. probably not your problem, but nothing should be overlooked, run it and get down in the hull while running and look for the water, you will find it eventually.
Marc

One of my next steps was to remove the trim tabs and check them out.  They appear to be fine now, but you never know.  One thing I should mention is that the mounting hardware for the trim tabs does not fully penetrate the transom. Should this be of any particular concern?

Thanks for all the replies so far and please keep them coming.  This thing is driving me crazy!

[flounderpounder225]

One thing I should mention is that the mounting hardware for the trim tabs does not fully penetrate the transom. Should this be of any particular concern?

No, that is normal, tab mounting screws do not fully penetrate the transom, none that I have ever seen anyway.  Just make sure you seal the screw holes good when you put them back on, my friend's boat, had the water coming in where the hose on the bennet tabs comes through the transom, but as you know it is hidden from view on the exterior of the transom because it is part of the triangular mounting bracket for the ram.  The installers did not user silicone or 4200 around the perimeter of that triangular piece and that is where the water was pouring in.

[John Jones]

Yeah, the bronze strainer type livewell pickup is what I'm talking about.

I had a brand new '02 Key West that must have been fitted on a Monday.  The metal receptacle for the plastic screw-in drain plug had zero sealant behind it, among other problems.  I don't think that would be an issue at speed though.

[themadpiper]

Guys, what about hull cracks?  Maybe I'm just thinking the worst but how do you best recommend testing for a hull crack?  I've been upside down and around this boat many times and there is no visual evidence of a crack from the exterior.  Besides filling the hull with water, as I've done many times, are there any other suggestions out there?

Thanks.

[John Jones]

I have heard of hull cracks that only opened up under the stress of running and could not be seen at rest.  That will be fun to find.

[gran398]

Standing by. Good discussion.

[themadpiper]

Re: hull cracks, I've always wanted to fill the hull with way more than 8" of standing water to find a potential leak/crack but have always been hesitant, not wanting to stress the hull.  I guess my question now is there any harm in doing so?  I could fill it up to the deck and see if it makes any difference, pressure wise.  I'm not sure if that would stress the hull too much.  Anybody have any insight on this?

Thanks.

[John Jones]

My 22-2 CCP accidentally got filled to the hatch covers once while on the trailer.  Didn't seem to hurt it.  Folks around here fill there boats with water when a hurricane is coming to prevent them blowing away.  Most say to put wooden blocks between the axle and frame on each side to prevent breaking the springs.   If I did that I would probably also block between the axles and the ground to keep the weight off the bearings and tires.  (Not that I am recommending any of this ;) )

[flounderpounder225]

Personally, filling the hull with water would be one of my last choices, waterlogging foam, stringer infiltration.. etc... that's just my opinion.  You say the water is coming in only when running?  Are you 100% positive of this fact?  Have you completely drained the boat on the trailer, then dropped it in the water and just let it sit for a few hours, then pulled it and drained it again, same angle everything equal.  If no water, then drop it in again and go run it for a short distance and return and repeat the draining procedure.  If you now have water, and all your thru-hulls are capped, I used plumber's putty once to shove in all my thru-hulls to eliminate that possibility, then I would be looking at that gap between your cap and hull behind the rub rail, near the stern, where water would be present even in calm water.  I really don't think you have cracks in your hull, that are only leaking under power, nothing is impossible, but I think that scenario is unlikely.

[gran398]

Have listened to all, and have one thought. The hull is dry at rest. She comes on plane, and the faster she goes, the more water intrudes the bilge.

The water enters the bilge directly, and is forced in at speed. There are only a couple of possibilities.

Instead of being mounted flush, the clam-shell pick-up for the livewell/washdown protrudes downward slightly at the hull bottom, allowing water to shoot up beneath it, through its drilled hole and up into the bilge. As JJ said, a little pressure goes a long way.

Any other below-waterline drain could also be a culprit.

If the clam-shell is leaking, its so low in the bilge you probably would never see it leaking, even if you were a little person/contortionist/dwidget.  



 

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[themadpiper]

All good thoughts guys.  

One thing that does come to mind is that it seems more water comes in when running with a follwoing sea.  This would lead to the rub rail as the boat is entering the water differently and "pushing" more spray up the hull and into the rub rail.  When heading into the seas she has a tendency to pound a little and and cut through the chop not throwing near as much spray as she does with a following sea.

On the livewell pick up, if it's leaking I'd think you would be able to see that when running.  Originally, there was a small leak there.  One of the pilot holes for the clamshell fitting was drilled too far and actually penetrated the bottom of the hull.  When the fitting was installed and the screw was in it's place, a little water would bubble up.  It was so slight that I had to scrub the dirt and grime away to feel around and sense the leak.  It was the size of a ball point pen and I repaired it.

My question is, if it were leaking from the clamshell fitting, would there be any scenario where it's leaking through but can't be seen?

Thanks.