HOSE BARB 1/2 NPT MALE TO 3/8

Feb 21, 2009
11
Beneteau 361 Sag Harbor
I'm taking your approach. Ordered the 316 stainless 1/4 npt to 1/2 hose barb from amazon Question when you drilled the epoxy/shaft tube for threading were you able to see the shaft? I'm hitting rubber. Is that the cutlass bearing. Should I keep drilling until I see the shaft? I filled the hole with water and it's not draining
 
Aug 22, 2017
1,609
Hunter 26.5 West Palm Beach
Often BSP threads & NPT threads will have the same pitch, so you can run a NPT tap into an existing BSP thread & the conversion is easy. I have done this at least 100 times on smaller sizes, like 1/8" npt. I would need to take a look in the Machinery's Handbook to see if that is true of the 1/2" size or not. I think that it is.

You can get info on BSP threads here - http://www.metricmcc.com/catalog/Ch7/7-703.pdf#[0,{"name":"FitH"},796] Those guys are also specialists in sourcing metric parts for use in the US. I've gotten BSP, Whitworth, metric trapezoidal thread tools, etc. from them over the years. They know where to find a lot of stuff that is not commonly available in the US.

I have seen the nylon 1/2npt to 3/8" hose barb fittings in Home Depot for a couple of bucks. McMaster Carr has 1/2" npt x 1/2" hose barb, salt water rated, bronze fittings for about $7.50. It's part number 9431K11. If you call them & ask, they can often get sizes that are not listed in the catalog.
 
Mar 20, 2016
594
Beneteau 351 WYC Whitby
There should be no rubber .Your cutlass is at the back of the tube where it exits the boat. Pull your Volvo dripless seal off ,maybe someone stuck a cutlass in the front of tube,which should not be there. The purpose of the nipple is to flow water thru the lower cutlass and out . On some beneteaus older ones had a bronze skeg holding the cutlass and do not need the nipple in the tube.You Do have to grease the Volvo every 50 engine hours or once a year and burp it once the boat is launched until your get water ,getting rid of air lock,so water is on the seals .
Check play in your lower cutlass it may be worn if it wasn't getting water supply.
Take a pic after your undo your Volvo drippless ,Volvo says replace it every 5 years ,however you can most likely double that or more ,mine was depends on how much motoring. Use the volvo grease, other types my not be good for the rubber
 
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Mar 20, 2016
594
Beneteau 351 WYC Whitby
That is a cutlass bearing that is not supposed to be there yes pull it out.
That has blocked the water nipple from supplying water to the cutlass at the rear of the tube. You should check lower cutlass for play remove prop and replace it.Did you just slide the Volvo dripless back? If you take it off there is a special tool to install it to protect the lips it's a plastic piece that snaps onto the shalt.
Get a straw plastic from McDonald's put some grease in it flatten it out to get into the seal,than squeeze the straw pushing the grease into the Volvo if that makes sense
 
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Feb 21, 2009
11
Beneteau 361 Sag Harbor
Ugh I bet a sloppy mechanic jammed the cutlass in there for some reason I'll try to pull it out and reinstall the volvo seal. Praying that the seal is good . Don't like issues so close to launch. Thanks all for your assistance.
 

Gunni

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Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
The shaft appears to be too scarred to establish a seal.
 
Jun 21, 2004
2,532
Beneteau 343 Slidell, LA
Interesting. I haven't replaced my shaft seal yet, so not quite sure what's inside. I lubricate the seal annually with Volvo seal grease and it doesn't leak a drop. Gunni, I agree with you, looks like the shaft is too scarred for the seal to function without leaking. Looks almost like "pipe wrench" gouges. Mechone, Do you have a part number for the Volvo seal installation tool? This is the first time that I have heard about the tool. Will likely change my seal & cutlass bearing on next haul out,
The seal is presently 12 years old; however, motor only has about 300 hours on it.
 
Dec 31, 2016
319
Beneteau Oceanis 351 Charlottetown
Those shaft marks make this job a good candidate for a PSS type seal.
 
Feb 21, 2009
11
Beneteau 361 Sag Harbor
The marks on the shaft seem to be dried grease. I'm launching in two weeks as I need this boat in the Hamptons to sleep on. Soooo.... I'm going to clean up the shaft, grease everything up and hope for the best. I can't be without a floating bedroom near my work. Will tackle this job next fall . I motored 150+ hours last year without leaks.
 
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Mar 20, 2016
594
Beneteau 351 WYC Whitby
Interesting. I haven't replaced my shaft seal yet, so not quite sure what's inside. I lubricate the seal annually with Volvo seal grease and it doesn't leak a drop. Gunni, I agree with you, looks like the shaft is too scarred for the seal to function without leaking. Looks almost like "pipe wrench" gouges. Mechone, Do you have a part number for the Volvo seal installation tool? This is the first time that I have heard about the tool. Will likely change my seal & cutlass bearing on next haul out,
The seal is presently 12 years old; however, motor only has about 300 hours on it.
When you order a new Volvo dripless it comes with it,I just keep it in the nav desk. Ordered it from General Propeller in Florida
 
Mar 20, 2016
594
Beneteau 351 WYC Whitby
My shaft looked like that it,s not a pipe wrench , it's galvanic corrosion, where the seal sits. Instead of buying a new shaft ,I added a flex coupling moving the shaft back onto a new surface, and then added a galvanic isolator from England ( safeshore marine UK) a lot cheaper higher amp rating, life time warranty with display off ebay . It also allows you to add a bigger anode, rope cutter,RD%20Shaft%20Coupling.jpg between prop and cutlass. R&D coupling
 
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Jun 21, 2004
2,532
Beneteau 343 Slidell, LA
Mechone,
Great recommendations to add the flex coupling to move the shaft aft. I really like the additional advantage of being able to use a larger shaft zinc. Did you notice a significant difference in anode depletion after adding the isolator? I really don’t have much, if any vibration in the drive train at cruising RPMs. Did you notice any reduction in vibration after adding the flex coupling?
 
Mar 20, 2016
594
Beneteau 351 WYC Whitby
I had some vibration before ,now nothing. No depletion of the zinc.Also my boat has a cast iron keel which rusted in spots every year ,this year no rust,however I did add 2 teardrop anodes on the wing.
 

Alfa

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Mar 19, 2015
38
Beneteau 31 North Vancouver
For those who contemplate replacing Volvo-Penta shaft seal on their boats, check improved design by Orbitrade, sold in UK by asap-supplies.com. Flexible shaft seal has port for greasing and removable barb fitting for water lubrication. However not all shaft seal dia are available with this features.

ASAP Supplies will put other stuff in the box for one shipping cost. Ask for hard copy Catalog of Marine Products. Prices on Web Catalog.

If you are only replacing barb fitting, check what size you realy need. 1/2"NPT seems to large. My Beneteau 31 with 40mm OD stern tube has original 1/8" NPT to 3/8 barb. 316 SST available from Amason.ca. Use high strength marine epoxi EZ Tex (easy 1:1 mixing ratio, by Pettit).
 

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Alfa

.
Mar 19, 2015
38
Beneteau 31 North Vancouver
One more comment to a discussed subject. I also installed on my sailboat R&D flex coupling for absorbing some shocks when shifting and very easy and convenient check of shaft/transmission alignment. Adding this coupling without shortening the shaft, however, moves propeller further away from the cutless bearing support.

General rule is to have propeller located at approx distance of shaft dia. Incresed distance with not properly balanced prop may increase vibrations. Prop striking floating object may also result in bent shaft.
 
Feb 21, 2009
11
Beneteau 361 Sag Harbor
For those who contemplate replacing Volvo-Penta shaft seal on their boats, check improved design by Orbitrade, sold in UK by asap-supplies.com. Flexible shaft seal has port for greasing and removable barb fitting for water lubrication. However not all shaft seal dia are available with this features.

ASAP Supplies will put other stuff in the box for one shipping cost. Ask for hard copy Catalog of Marine Products. Prices on Web Catalog.

If you are only replacing barb fitting, check what size you realy need. 1/2"NPT seems to large. My Beneteau 31 with 40mm OD stern tube has original 1/8" NPT to 3/8 barb. 316 SST available from Amason.ca. Use high strength marine epoxi EZ Tex (easy 1:1 mixing ratio, by Pettit).
I went with 1/4 npt because already owned the the tap. Used a half inch hose barb because that's the size of the through hull. Keep it simple
 

Alfa

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Mar 19, 2015
38
Beneteau 31 North Vancouver
Rich, I can see your point with 1/4" NPT fitting. Be prepared however, that you will have to pull the shaft aft when drilling and tapping new thread in the stern tube; there is no room with shaft inside.

It is much easier to use new fitting with the same size thread. Use Dremmel tool to remove epoxi around old fitting to expose hex, than unscrew NPT male. Do not force it, if it's stuck, heat brass fitting with soldering iron. This will soften epoxi allowing you to remove old fitting without destroying thread in the stern tube/remaining epoxy. Clean surfaces with acetone, apply high strength marine epoxi on threaded fitting and install. Put more thickened epoxi around the base of the fitting and stern tube. Use quality components and observe cleenles for this project.

As pointed by Mechone, remove cutless bearing from this side of the stern tube!
Good luck.