Re: {Beneteau Owners} Slow leak - stumped

[bjgr...@verizon.net]

I had a 361 with the infamious slow leak and I thought it was the shaft seal leaking. Replaced the shaft seal and the leak persisted.  The water was pooling around the base of the shaft seal.  Then I thought it was coming from under the fuel tank and was about to remove the tank when I learned about the leak at the prop end of the shaft tube.  On the 361 there was very little shaft so a shaft zinc wouldn't fit. I had an auto prop with the zinc on the prop.  Where the shaft exits the tube is the cutlass bearing.  It turned out the the the seal around the outside of the shaft tube where the tube entered the hull was leaking. It was traveling up to the boat between the shaft tube and the fiberglass and exiting near the end of the shaft tube and collecting near the seal.  Pulling the 5200 from around where the shaft tube exits the hull , draining and putting new 5200  fixed the problem.  Since your checking everyting else you may still have this problem.    I may still have a picture of this.  I can probably do a drawing that would help.   Bruce (Breezy)

Jan 21, 2015 08:12:44 AM, benetea...@googlegroups.com wrote:

A slow leak started somewhere aft of the engine in our 411. Read several similar sounding threads on here about a possible leak that can develop where the stern tube enters the boat. When we on the hard this year I got to take a closer look. It sure looke like this was the culprit. There was some partially cured "caulking" (felt like slicone-based) that was starting to pull away. The caulking was covering a small crack that went a little over 1/2 the circumfrance on the upper side only. I cleaned it up, sealed it back up but when we splashed, the leak still persists with the exact same flow rate!

My question to this group is, what other sources of water ingress could there possibly be (see the end of this for details on how I did this repair in case there are issues there)?

Rudder post is fine and the whole area aft of the aft cabin bulkheads is dry (where the rudder post, exhaust, bilge pump outlet and a few other above the waterline outlets are).

The seawater intake thruhul has been replaced and is dry. Same for the smaller thru hull that feeds the dripless shaft.

The dripless shaft is not dripping.

What about the seal where the shaft exits the stern tube? I would have thought that any water flowing up through there wouldn't exit the stern tube (assuming the dripless seal stayed sealed). Having never removed the shaft, I'm ignorant as to the details of how all that is put together.

For reference, here are more details about -how- I sealed this up when we were on the hard in case there are any issues with this process.

I remove the old goop and sanded the surface to remove any old bottom paint and caulcking and to create a rough surface. I then opened up the crack a bit with a small pick. To seak it all up we painted the crack, the surrounding surface and about 3/4 of the exposed tube with primer then did two applications of Intrlux Watertite pre-thickened epoxy, sanding in between. I used a small mixing stick to "push" the watertight as far into the crack as it could until it was squeezing out. One of the boat yard pros inspected it during the job and the finished product.

Thanks all.

-skye


--
Largest Beneteau group, over **1050** members and growing.

To post to this group, send email to Benetea...@googlegroups.com
To unsubscribe from this group, send email to Beneteau-Owne...@googlegroups.com
For more options, visit this group at http://groups.google.com/group/Beneteau-Owners
contact denny.we...@gmail.com, or ume...@comcast.net if you have a list management question
---
You received this message because you are subscribed to the Google Groups "Beneteau Owners" group.
To unsubscribe from this group and stop receiving emails from it, send an email to beneteau-owne...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

[sc]

Hi Bruce. What you are describing, sounds just like what we thought the problem was. We too pulled away the old caulking (wasn't 5200 that's for sure) and epoxied. Still leaking though (and I was sooo sure this was it). We are going to haul again in a few days while our rigger plays with our rig. Sucks to play process of elimination when lifting costs $$.

I'm wondering if the seal around the shaft where it enters the stern tube could be leaking?

[Mark J Wilme]

i don't see the original email but have you tried sprinkling talcum powder over the dry bilge in the area to better trace the source of the leak  ?

Mark Wilme
Mark....@Gmail.com

+1 (508) 826 5607

www.linkedin.com/in/markwilme            

On Thu, Jan 22, 2015 at 12:27 PM, sc <skye...@gmail.com> wrote:

Hi Bruce. What you are describing, sounds just like what we thought the problem was. We too pulled away the old caulking (wasn't 5200 that's for sure) and epoxied. Still leaking though (and I was sooo sure this was it). We are going to haul again in a few days while our rigger plays with our rig. Sucks to play process of elimination when lifting costs $$.

I'm wondering if the seal around the shaft where it enters the stern tube could be leaking?

[bjgr...@verizon.net]

The shaft goes into the cutlass bearing and water is supposed to enter here, lube the shaft and should run all the way up the tube to the shaft seal.  That's why you get water when you burp the seal.  The water stays in the shaft tube.  It's when it gets around the tube, like where we described, that is a problem.  If your hauling, take off all the caulk around the shaft tube where it comes out of the hull.  Make sure you clean all the loose material, some water may drain out from the new opening which will be a tell tale.  May want the hauler to tilt the stern down a bit to encourage drainage.

[sc]

Hi Mark,

I've been able to trace the leak back to where it disappears under the hull liner under the fuel tank. There's a bit of room around where the shaft comes up that I'm able to shine a light in there and see the moisture. This is under the fuel tank at this point. The hull is totally dry beyond this point.

Everything points to the same problem other have described here. Maybe my fix with the epoxy failed for some reason. Will see what it looks like after we haul out I guess.

[bjgr...@verizon.net]

I found a picture that is pretty good quality so you should be able to zoom.  Where the arrow ends is where the problem was. As you can see I was blown away that this was the problem.  One of the guys at Winters in NJ told me about the problem and he was right on.  Good luck. B

[sc]

Thanks Bruce. That's exactly what I thought the problem was too. I was _sure_ I fixed it .... But it seems that either I did the repair wrong or it's something else. Hauling on Monday to take another look.

-sc

[GBS]

I'm also curious about this, our 361 has some water, stern tube bilge about half full, from time to time. it can be dry for weeks then have water there. I dipped a finger and did a small taste test and concluded fresh but starting to wonder if this might not be a very accurate way to determine it.

Does this leak "come and go" or is it a steady slow leak? For me I know it can be dry for a month then next time I'm there I find water. Also anyone have a better way to determine if its fresh or salty? I dont really want to sample more from either :o)

 

Thanks!

[sc]

In my case it's a steady leak. And I can taste salt water with certainty, when in salt water of course.

I did some experiments with food colouring to pinpoint the area the leak is coming from. That helped.

[sc]

Update.

Unfortunately, I've verified that the common location of this leak (where the stern tube enters the hull) is certainly not the source in our case. It too bad because this would be an easy fix.

Before we hauled, I did some experiments with food colouring to confirm the general area of the leak. I could see quite a lot of water under the tube *aft* of the shaft seal, under the fiberglass platform the fuel tank sits on (so I put red die in that water). No water was seen aft of about the center of the fuel tank. This is approx where the shaft tube exits the hull from the inside of the boat.

After we hauled in Ft. Pierce, I detected water (with red die present) draining around the shaft seal/cutlass and NOT where the stern tube exits the hull on the outside. This means that there is a way for water to migrate from inside the hull, outside of the tube to inside the tube somewhere along its length (and vice versa of course).

I've now pulled my shaft (that was fun). Shining a light up the now empty tube I can see what appears to be a seam or a joint in the tube around the area where the tube exits the hull on the *inside* but before the end of the tube. Measuring from the prop end of the shaft, this seam would be a little more than 1/2 way along the shaft. There is also a slight amount of wear on the shaft at this location. Unfortunately this area, inside the boat, is covered by the fuel tank. My tank needs to be cleaned so I'm emptying and removing it to see what we can see.

Will report back when I find out more.

-sc

[Skye Cove]

Pic of what can be seen down the tube.

--
Largest Beneteau group, over **1086** members and growing.

To post to this group, send email to Beneteau-Owners@googlegroups.com
To unsubscribe from this group, send email to Beneteau-Owners-unsubscribe@googlegroups.com

For more options, visit this group at http://groups.google.com/group/Beneteau-Owners
contact denny.we...@gmail.com, or ume...@comcast.net  if you have a list management question
---
You received this message because you are subscribed to the Google Groups "Beneteau Owners" group.

To unsubscribe from this group and stop receiving emails from it, send an email to beneteau-owners+unsubscribe@googlegroups.com.