Stern Tube Water nipple corroded

[Richard Suchecki]

On my Beneteau 423, there is a water nipple on the forward end of the stern tube for the prop shaft. Apparently, the nipple is made of brass and it has failed on my boat. When I say failed, I mean that it corroded and broke off at the point where it screws into the stern tube. I have called Beneteau and the Dealer and have been advised to find a replacement at a local Marine supply store. The problem is water squirts in where the fitting broke and I haven't extracted the broken piece that is threaded into the tube. Has anyone experienced this issue before? If so, do you know the size and thread pitch for the Brass nipple? I would like to buy the replacement to have on hand when I extract the broken piece.
I currently have a piece of rubber compressed with a hose clamp to keep the water at bay.

Thanks,

Rick

 

[TAK]

Richard, Search for the topic on this site and also the Benrteau423 yahoo site. There were several threads on how to extract and replace it. I had trouble extracting the remnants of the old one and had one of the shops at our marina fix it. I think it was about an hour labor. Also the suggestion is to replace with bronze.

Paul
S/V Summerhaven

 

[Paul Mermelstein]

This is a well known problem on most Beneteaus from that era including the 473, 423, 393, etc. Beneteau dealers often recommend replacing the nipple every 3-5 years as part of preventive maintenance.

 

[BigEasy]

Richard,
As others have mentioned, this is a common problem on all Beneteaus of your vintage. The puzzling thing is that Beneteau will no longer sell you a replacement fitting?? Their advice is to purchase one from a hardware store. Problem is that the ones that I have found have much thinner walls than the OEM fitting. Not sure if the fitting size is common for all boats. On my 343 with a 25mm shaft, the fitting size is 1/8npt x 1/4" barbed hose. These smaller fittings are not available in bronze; only brass. As Paul stated, there is much information on the Yahoo 423 site. The preferred method of replacement on the 423 site is to add a layup of cloth and resin around the stern tube (at the location of the existing fitting) to beef up the thickness of the stern tube to secure the thread fittings more securely. Then, redrill, and tap for a larger size Stainless Steel fitting.
I purchased a fitting kit from Annapolis Yacht Sales for approximately $25. The kit number is #37297 and includes a brass fitting, epoxy, and instructions for replacement. Unfortunately, the fitting included in the kit does not correspond to my OEM fitting.
If you can't find an adequate fitting locally, you might try ordering from McMaster Carr online.
Let us know the outcome.

 

[Richard Suchecki]

Thank you Paul, TAK, and Big Easy. Interesting my Dealer didn't mention your comments about the periodic replacement. I have a call into Annapolis Yacht Sales to inquire about their 'kit'. I believe the fitting on my 423 is 1/8"npt x 3/8". At least that is what the barbed end measures. I might try to find one locally for a temp fix.
When you say the fitting in the Annapolis Kit does not match the OEM fitting, what part doesn't match? the npt fitting or the barbed end?

With much gratitude!!

Rick

 

[BigEasy]

Rick,
The barbed end on the Annapolis fitting is 3/8"; that is larger than my fitting. I think the barbed end on my fitting is 1/4".
The fitting included in the kit was not as thick/robust as the OEM fitting. Also the OEM fitting did not have a hex mid way between the npt end and the barbed end, it was like a nipple. The abscence of the hex allowed for the epoxy "fillet" to be mounded up around the shaft of the fitting to strengthen the attachment point because there aren't too many threads engaged in the thin fiberglass shaft tube. I find it unsettling that Beneteau wont supply the OEM fittings; there are likely thousands of Beneteaus that have this poorly designed system; the least they could do is supply the replacement parts.
Beneteau released a service advisory in April 2012 that recommending that the fitting be inspected annually, " you should lightly pull on the hose and tap the hose barb from the side. If it should break , you should replace it"!!!! That is one heck of an advisory!

 

[Richard Suchecki]

Thank you Big Easy!! Interesting, the barbed end of my fitting is 3/8". My fitting like yours does not have the Hex midway. I spoke with Kathy Streeter at Annapolis Yacht Sales and she indicated that they are supplying the fitting with the Hex for two reasons - 1, it is what is available; and 2, It give the epoxy they supply with their kit a bit extra to anchor to when installing the new fitting. Their instructions also indicate you need to have the boat pulled, the water drained from the tube and let the area dry for 2-3 days before installation of the new fitting and epoxy. This process is the same whether for a broken fitting or for a periodic replacement. Which is OK if you have a haulout planned already. But for a broken fitting, that is quite a bit of extra expense. There has to be a better way!!

I have ordered the kit and will post my results when done.

Rick

 

[Gunni]

Yes, you do this job on the hard. That is why they recommend doing a replacement pro-actively. Critical item, it can sink your boat.

 

[BigEasy]

Just got two estimates on the Beneteau replacement fitting kit from sources in England. Both sources wanted approximately
$110 GBP including VAT & shipping.! Would be nice to just unscrew that sucker and screw another in with a little 4200 & Teflon tape; however, $140 US is a bit much to pay for the fitting & a small packet of epoxy. I guess that is why Beneteau USA stopped selling the imported kit. On next haul out, I guess I will do the stern tube mod. by adding a few wraps of 2" cloth/tape and resin, then tap an appropriate sized hole for a new 316 stainless steel fitting. On future haulouts I will be able to unscrew the fitting & check it or replace it as needed.

 

[Gunni]

This isn't a particularly good application for stainless steel. Bronze doesn't crevice corrode when sealed in a low oxygen install like this.

 

[Richard Suchecki]

I am thinking that the SS solution will get me to the point where the installation of a PSS shaft seal can be installed. Curious though . . . As long as the boat is in regular use; ie water moving through the fitting and tube, wouldn't that supply sufficient Oxygen via the water to prevent and oxygen depleted condition?

 

[BigEasy]

Well its either going to be brass or stainless because I have searched for hours for a bronze fitting with 1/8 inch npt threads. Cant find a manufacturer that makes this small of a fitting out of bronze. Only way is to find a bronze nipple and have a machine shop make one. Actually I think the OEM fitting is brass; it does however have a much thicker wall than anything that I have been able to find. Suspect the threads are metric. Beneteau dealers & the Marion, SC parts dept all recommend using a brass fitting; however, I really don't think that is the best practice. Might be OK in Northern climates where boats are hauled annually and out of the water for 5-6 months; however, in Southern climates where boats are hauled every two years for a week or two, I don't think that these thin walled brass fittings are a good idea. If anyone has a suggestion, please post it. Very frustrating that this dilemma can sink your boat.

 

[Gunni]

Yes, the original is brass, but you don't have to stay with that. You can glass in a threaded nipple to the shaft log and screw in a threaded pipe section which is replaced during regular hauls. And there is nothing that says you have to stay with 1/8" tubing. You can go to common 1/2"

 

[BigEasy]

Good suggestion Gunni, last time I inspected the fitting on my boat there wasn't much of an opening inside that 1/8" fitting because of marine growth. Probably not much flow thru that small diameter fitting.

How do you deal with your fitting? Did you convert to another shaft seal?

 

[Gunni]

I have the parts to glass in a fitting...and the part numbers for a PYI seal kit...and I am leaving well enough alone for now, along with a maple wood plug of the correct size taped to the fitting....it ain't broke I'm not going to fix it. I just greased the volvo seal boot last week.