Why's the boat leaking?

britboating

Cadet
Joined
May 26, 2021
Messages
6
Hi Everyone!

Appreciate everyone's replies and answers in advance.

Newbie boater here as 2020 brought a boat with the pandemic. Have some questions regarding my 1990 Caravelle Interceptor 2300 IO with an OMC Cobra 5.7 (Mod No 385689 outdrive).

Like alot of 1st time boat purchasers, my wife and I had the wool pulled over our eyes and we bought a boat that ended up needing alot of work. Only taken out twice on our own to find out the transom was completely rotten and a bit of the stringers rotten as well (had lots of water leaking in, where the bilge pump couldn't even keep up after a few hours on the water). Had them replaced as well as the transom. This ended the 2020 boating season for us as we had this done and winterized at the same time. Our initial plan was to get the necessary repairs done and opt to forgo the "optional" ones (like the bellows - mechanic said it was recommended to replace but probably had one or two more seasons in them) in order to sell in 2021 and start over.

Come 2021.

We've grown to really like the boat, but we're still dealing with water intrusion issues.

My main question is where do you believe (or most likely suspects) the water is coming from and what would be a priority list in terms of repairs?

A couple considerations:

1. The bilge pump has no float attached to it, just a pure on/off switch. It's either running or it's not. I sometimes try to act as the float switch and manually turn it on/off but usually end up just leaving it on so I don't forget. It basically just constantly tries to pull water. Bad for the pump, I know. It appears to be getting old and should be replaced as it even sometimes has fuse issues. It probably has enough water coming in to be dribbling water out every few minutes or so. If I leave it off for about 20-25 minutes it probably can pump out approx a gallon when I turn it back on. I know this needs to be replaced, but is this just treating the problem?

2. The bellows were not replaced, however, from visual inspection they look okay.

3. The plug only screws in about 3/4 of the way (some hills/valleys are exposed). It's tight as I can make it though by hand before we set off. I've tried multiple plugs. Same thing. The seals around the outside of the plug were resealed when the transom was replaced.

4. The last time we took the boat out (about two weeks ago) was having a fuse issue with bilge pump and water ran farther up in bilge. Had some wood pieces some back down. They looked old but wondering if some of the stringers/transom could still be bad?

Lots of questions and considerations I know. Just looking for some advice as the fiberglass/hull looks to be sound (on the outside) up the boat and I'm not sure the best way to move forward. I'm pretty mechanically inclined and can probably fix some/most of this myself, unless it's more transom/stringer work. Just don't want to have to wait 1-2 months for a mechanic to finally get to it for it to be something fairly simple, or charge me $100s for something that'll take me a weekend.

How would you go about this? Where could that much water be coming from? How would you determine where the water is coming from?

Thanks!
 

JimS123

Fleet Admiral
Joined
Jul 27, 2007
Messages
8,163
First, crawl under the boat and verify there are no cracks. Then, remove the doghouse, rear seats, etc - anything that will reduce visibility.

Raise the bow of the boat on the trailer and drain all of the water. Then get down on your hands and knees with sponges, rags and a bucket and remove every single drop of water. The boat needs to be bow high to ensure it all runs to the bilge.

Then, sit in the boat as someone launches it and get down on your hands and knees again to look where the water comes it.

If the transom was replaced, the bellows had to be taken off anyway, so the labor charge was already in play. Not a good idea to put the old one back on.

If you're unsure of the plug, pipe dope it or use teflon tape.

When you're in the water and if you don't see any water intrusion, start the engine and look again.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Jul 23, 2011
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49,546
agreed, since the drive had to come off and the motor had to come out to replace the transom. not sure why they didnt replace the bellows

with a dry bilge, back the boat in the water (no need to remove from trailer)

get in the bilge with a flash light, mirror and your phone (can use the camera to see where you cant stick your head). and look.

you will find the leak.

if no leak, fire up the motor and then look.
 

britboating

Cadet
Joined
May 26, 2021
Messages
6
First, crawl under the boat and verify there are no cracks. Then, remove the doghouse, rear seats, etc - anything that will reduce visibility.

Raise the bow of the boat on the trailer and drain all of the water. Then get down on your hands and knees with sponges, rags and a bucket and remove every single drop of water. The boat needs to be bow high to ensure it all runs to the bilge.

Then, sit in the boat as someone launches it and get down on your hands and knees again to look where the water comes it.

If the transom was replaced, the bellows had to be taken off anyway, so the labor charge was already in play. Not a good idea to put the old one back on.

If you're unsure of the plug, pipe dope it or use teflon tape.

When you're in the water and if you don't see any water intrusion, start the engine and look again.
If you run the engine and water starts intruding from there would you assume it's the bellows? Thanks for the advice.
 

britboating

Cadet
Joined
May 26, 2021
Messages
6
agreed, since the drive had to come off and the motor had to come out to replace the transom. not sure why they didnt replace the bellows

with a dry bilge, back the boat in the water (no need to remove from trailer)

get in the bilge with a flash light, mirror and your phone (can use the camera to see where you cant stick your head). and look.

you will find the leak.

if no leak, fire up the motor and then look.
They definitely recommended to replace the bellows, but it was going to be another $500ish, I believe. Was trying to minimize the damage, as we had owned the boat less than 3 weeks. Essentially asked if it was an absolute need at the time, or more so a general rule of thumb. If it's the reason it's leaking I'm of course going to be eating my words. Do you think that much water would be coming from bad bellows though?
 

hugh g

Petty Officer 1st Class
Joined
Dec 21, 2002
Messages
225
There shouldn't be any water in your bilge, period. Bilge pumps are there in case of emergency, not to remove water routinely seeping in & most of them are garbage anyway & wouldn't save your butt in an emergency because the crap installed by boat builders are just that, crap with not enough GPH capacity to pump out your bathroom sink.

Now back to your leak. Have the bellows replaced, post haste. It may be dry rotted or has a slit you can't see without removing it. If you keep running it with that leak you're looking at replacing the gimbal bearing & possibly u- joints.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Jul 23, 2011
Messages
49,546
They definitely recommended to replace the bellows, but it was going to be another $500ish, I believe. Was trying to minimize the damage, as we had owned the boat less than 3 weeks. Essentially asked if it was an absolute need at the time, or more so a general rule of thumb. If it's the reason it's leaking I'm of course going to be eating my words. Do you think that much water would be coming from bad bellows though?
bellows kits are about $100 for all the bellows. you already paid for the labor.

yes, boats have sunk due to bad bellows

however more importantly, a leaking bellows could be rusting your u-joints and input shaft on the drive, causing you thousands of more dollars.

find the leak - now
 

hugh g

Petty Officer 1st Class
Joined
Dec 21, 2002
Messages
225
They definitely recommended to replace the bellows, but it was going to be another $500ish, I believe. Was trying to minimize the damage, as we had owned the boat less than 3 weeks. Essentially asked if it was an absolute need at the time, or more so a general rule of thumb. If it's the reason it's leaking I'm of course going to be eating my words. Do you think that much water would be coming from bad bellows though?
If you slip your boat & that bellows is leaking, some day you'll show up & find your boat underwater. A $500 bill is chump change compared to what that may cost you.
 

britboating

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Joined
May 26, 2021
Messages
6
If you slip your boat & that bellows is leaking, some day you'll show up & find your boat underwater. A $500 bill is chump change compared to what that may cost you.
We keep it trailered, luckily. And I'm with you, was just trying to take care of "absolute necessities" when we were having the transom work done end of season last year.
 

britboating

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Joined
May 26, 2021
Messages
6
bellows kits are about $100 for all the bellows. you already paid for the labor.

yes, boats have sunk due to bad bellows

however more importantly, a leaking bellows could be rusting your u-joints and input shaft on the drive, causing you thousands of more dollars.

find the leak - now
I've ordered the bellows and planning on replacing them over the long weekend coming up. Definitely don't want more spend. Appreciate the advice and help.
 

JimS123

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Messages
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I've ordered the bellows and planning on replacing them over the long weekend coming up. Definitely don't want more spend. Appreciate the advice and help.
Don't replace them yet. Find the leak first.

Bellows keep the lake water out of the boat. If they are leaking they will leak whether the engine is running or not. They usually leak worse if the drive unit is up.

If you put the boat in the water and its not leaking until you start the engine, you may have bigger problems. For example, if you have a cracked block you might not want to spend the big bucks needed to replace the engine. Thus, doing the bellows would have been a waste of time.

On another note, the reason bellows cost a grand or more is because they are labor intensive and a real PITA. I did one once, and now I'm happy to let someone else do it.
 

roscoe

Supreme Mariner
Joined
Oct 30, 2002
Messages
21,739
Don't worry about damaging your bilge pump by running dry.
Whether you have a centrifugal or diaphragm type pump, it can be run dry.
The only long term damage will be minimal if any at all.
 
Joined
Mar 1, 2005
Messages
956
Adding a float to a manual bilge pump is super easy. If I remember you just slap it on the bottom, tighten a few screws, and voila.

You can also cheaply buy a flexible camera for your cell phone. They sell them in hardware stores to help you see behind walls, in pipes, etc. Using that to see inside the bilge might be helpful.
 

Toyelectroman

Petty Officer 2nd Class
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Dec 20, 2016
Messages
198
A little insight on how I determined my leak(spoiler alert it was the transom). During the week on a not so crowded day i launched the boat. I didn't start it, just kept it tied to the dock. I used a endoscope camera and saw the drips of water coming from the bolts that hold the outdrive to the transom. Amazon sells endoscope cameras for like 35, and it was the only way I would have found my leak
 

BRICH1260

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Jul 6, 2011
Messages
1,371
In addition to all of the above, if you have any thru hull, check them and their hoses. Also check your entire cooling system including intake and exhaust rubber passages. Also make sure your transom assembly is tightened properly forming a proper seal with the hull.
 

britboating

Cadet
Joined
May 26, 2021
Messages
6
Don't replace them yet. Find the leak first.

Bellows keep the lake water out of the boat. If they are leaking they will leak whether the engine is running or not. They usually leak worse if the drive unit is up.

If you put the boat in the water and its not leaking until you start the engine, you may have bigger problems. For example, if you have a cracked block you might not want to spend the big bucks needed to replace the engine. Thus, doing the bellows would have been a waste of time.

On another note, the reason bellows cost a grand or more is because they are labor intensive and a real PITA. I did one once, and now I'm happy to let someone else do it.
So update here. Looking for more unbiased opinion.

Bellows ended up not coming in over the weekend, so couldn't replace them even if I wanted to.

Established where a leak is coming from though. Not sure if it's the only one though. Didn't have capability to test the bellows (filled up the bilge to the pump from the inside), but the plug is definitely leaking. However, it's leaking around the outside of the housing. Think some 3M 5200 will seal it up?

Second question, after some stronger evaluation of the bilge (where I can reach) there appears to be additional wood coming from somewhere (see attached). This picture is of the slot below the bilge pump that goes down to the plug hole. Think I may take some posts above advice and get a flexible camera to check further.

I was told the last fall when the transom was replaced that the stringers were in "good" condition, and weren't needed to be replaced. The boat was trailered over the winter, with a cover. Do you think this wood could be residual from where the transom was replaced? Or do you think the stringers are shot too? Just don't want to take it back to mechanic for them to try to skirt around it or try to charge me another couple thousand to dismantle the boat again, etc. and not have the boat for 1-2 months, or longer, of prime season. More importantly though, don't want an unsafe boat. Thoughts?

Thanks again everyone for your help and responses!
 

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gmacp58

Cadet
Joined
Feb 16, 2019
Messages
11
I had a leak that was hard to detect. When water splashed in the transom the water entered thro the sidewall where the motor cables go thru. There was a splash boot over the cables but it was old and no good, and that's where it leaked. The visible part of the boot was ok, but the underside of it was cracked and rotted, and the source of my leak.
 

JASinIL2006

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Feb 10, 2012
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5,673
That rotted wood looks VERY suspicious to me... I cannot imagine replacing a transom and leaving behind wood from the removal. I personally would be drilling some test holes in the stringers to check for rot.
 

JimS123

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The stringers may be rotten, or maybe not. Regardless, rotten stringers wouldn't be a source of the leak.

If the plug is leaking, obviously it wasn't installed correctly. I would think 5200 would be good, but not just smeared on the outside. The entire assembly should be removed and sealed completely when re-installed.
 

Commander_47

Petty Officer 3rd Class
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Nov 18, 2016
Messages
86
It sounds to me like you have a pretty serious leak. If you have to run your bilge pump to stay on the water something is wrong.

I would be highly upset if I paid to have the transom replaced and they botched installing a drain plug!!!! You might want to just remove whatever the marina installed and put in a new one. Maybe oversize screws and the 5200 sealant won't hurt. If the drain fixture is stripped, or not installed right, best to replace the whole thing. It's not a costly or hard job.

Bellows is a given, and just good insurance anyway. If the new plug stops the leak, use the boat for this season. Then replace the bellows at your convenience. A leaking bellows is normally the cause for water in the bilge.
 
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