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ahalfon 05-28-2013 10:56 AM

Shaft Through-hull Leak

I recently discovered that the prop shaft though-hull in my Pearson 28 was leaking. I initially though it was the Dry-Seal installed three years ago, but upon further investigation realized the leak was due to the sealant breaking down around the through hull (probably as a result of diesel spillage a couple of years back).

Hear's my question - does it make sense to apply 4200/5200 from inside the boat or do I have to replace the through-hull ASAP? I'd rather not haul out if possible, but only if it's safe (the water is seeping in pretty slowly at this point.)

Also: any opinions on using sealant vs. underwater epoxy such as WaterWeld?


SchockT 05-28-2013 11:15 AM

Re: Shaft Through-hull Leak
What you are referring to (I think) is called the Shaft Log, and it is a tube that is fiberglassed into the hull for the prop shaft to pass through. If the log itself is truly leaking, and it is not the seal, or stuffing box connection that is leaking, then I would say a proper repair is needed. I am not sure bodging some 5200 all over it constitutes a proper repair, even though it seems like the easiest thing. Often the "easy" fix is exactly the opposite. If the "glue" doesn't solve the problem, then you have to clean all of that stuff away before you can repair it properly.

If the log is leaking then you likely have a crack in the fiberglass, or perhaps a misaligned shaft has worn through it? Either way, I think it warrants closer investigation, and likely grinding back the glass and putting more layers on.

Do you have any pics of the problem area?

deniseO30 05-28-2013 11:17 AM

Re: Shaft Through-hull Leak
Photo would help. If it's a "shaft log" it's most likely years of vibration have weakened the fiberglass. It is something that should be done with the boat out of the water. the area in question needs to be dry before you start repairs.

tommays 05-28-2013 12:49 PM

Re: Shaft Through-hull Leak

If it is the tube mine had internal BLISTERS that almost sank the boat as the stuff the PO gobed on leaked pretty bad

ahalfon 05-28-2013 01:29 PM

Re: Shaft Through-hull Leak
Thanks for the quick responses; I'll take some photos this aft. It is indeed the shaft log (thanks for the correction); the water seems to be seeping in trough the sealant around it but it's not easy to tell... I fully intended to do this right, but was wondering if the real repair could wait until the end of the season... (I just got the boat in the water and am dying to go sailing :)

ahalfon 06-20-2013 11:32 AM

Re: Shaft Through-hull Leak
Sorry about the long delay. I had to go out of town (only to find things in much worse condition when I got back...)

The leak is coming from the area that the light is falling on right below the log:

And here is a close-up:

I'm getting ready to haul out the boat, but would like to get a better sense of the extent of the job beforehand. Looking at the log, it almost seems like a through-hull rather than the typical glassed-in arrangement. Can that actually be the case? If not, how extensive is the replacement job?


jameswilson29 06-20-2013 11:50 AM

Re: Shaft Through-hull Leak
You have a Pearson 28-2 with a stuffing box attached to the shaft log, with 10 lbs. of caulk around it.

Here is what the shaft log on a Pearson 28-1 looks like: SailNet Community - jameswilson29's Album: Winter repairs: replace stuffing box hose (See photo 12 of 21).

It looks as if someone improperly addressed a mismatch between the shaft log and the stuffing box by caulking the area or tried to stop a leak from the shaft log with caulk.

I would pull the boat, disconnect the coupling from the transmission, remove the coupling from the propeller shaft, remove the stuffing box, pull the prop shaft, remove all the caulking and thoroughly examine the shaft log and your stuffing box.

A failure in that area can lead to a very fast sinking boat. Pearsons are generally well-built boats. I doubt a failure developed there from normal usage, vibration, friction or some other normal wear and tear. I would not be surprised to learn that some extreme lateral force was applied to the propeller shaft, either through an impact in the water or a fall on the hard, and one of the POs or a sloppy mechanic simply replaced the bent shaft and stuffing box instead of properly repairing the shaft log.

ahalfon 06-20-2013 12:59 PM

Re: Shaft Through-hull Leak
You're spot on - I caught a line in the prop about a year an half ago, which probably has something to do with this. (Although the gobs of caulk were there since I got the boat 10 years ago, perhaps concealing an earlier failure.)

I'm certainly haling out and dealing with this now - just trying to get a sense of the proper way to fix this, and also find out where to get the parts.
The arrangement on the 28-2 is very different than the 28-1, and resembles a thourg-hull, though that may be wishful thinking on my part :) If anyone has an image of what it looks like outside the boat that would be tremendous!

I've already replaced the original stuffing box with a LasDrop Dry Seal a few years back, so am familiar with the process of removing the coupling, etc.
I don't know anything about the shaft log though, and it'd be great to find out more before starting the project (I'm using a mechanic but would still like to know as much as I can).


ahalfon 06-20-2013 01:08 PM

Re: Shaft Through-hull Leak
Here's what I think might be under all that sealant:

Alex W 06-20-2013 01:12 PM

Re: Shaft Through-hull Leak
I thought I remembered my shaft log being fiberglass, but a quick look on the p28forum photos showed another using a brass through hole.

I will be at my boat later on today and can look at the stuffing box to remind myself of how it is setup.

Either way it sounds like hauling and close inspection are going to be necessary. You have way too much caulk there, that is always a bad sign to me.

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