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HOSE BARB 1/2 NPT MALE TO 3/8

Discussion in 'Ask A Beneteau Owner' started by Bluenose, May 17, 2018. Add this thread to a FAQ

  1. richpinto72

    richpinto72

    Joined Feb 21, 2009
    10 posts, 1 likes
    Beneteau 361
    US 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
     


  2. JimInPB

    JimInPB

    Joined Aug 22, 2017
    1,399 posts, 409 likes
    Hunter 212 & 170
    us 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.
     


  3. Mechone

    Mechone

    Joined Mar 20, 2016
    163 posts, 40 likes
    Beneteau 351
    ca 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
     


    Last edited: Apr 7, 2019
  4. richpinto72

    richpinto72

    Joined Feb 21, 2009
    10 posts, 1 likes
    Beneteau 361
    US Sag Harbor
    So it looks like there is a rubber bearing in the shaft tube. Do you think I should pull it out? I ordered the volvo grease
     

    Attached Files:



  5. Gunni

    Gunni

    Joined Mar 16, 2010
    5,925 posts, 1,480 likes
    Beneteau 411 Oceanis
    US Annapolis
    That shaft has been destroyed.
     


  6. Mechone

    Mechone

    Joined Mar 20, 2016
    163 posts, 40 likes
    Beneteau 351
    ca 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
     


    Last edited: Apr 9, 2019
  7. richpinto72

    richpinto72

    Joined Feb 21, 2009
    10 posts, 1 likes
    Beneteau 361
    US 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.
     


  8. Gunni

    Gunni

    Joined Mar 16, 2010
    5,925 posts, 1,480 likes
    Beneteau 411 Oceanis
    US Annapolis
    The shaft appears to be too scarred to establish a seal.
     


  9. BigEasy

    BigEasy

    Joined Jun 21, 2004
    1,115 posts, 289 likes
    Beneteau 343
    US 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.
     


  10. BrianRobin

    BrianRobin

    Joined Dec 31, 2016
    222 posts, 80 likes
    Beneteau Oceanis 351
    Ca Charlottetown
    Those shaft marks make this job a good candidate for a PSS type seal.
     


  11. richpinto72

    richpinto72

    Joined Feb 21, 2009
    10 posts, 1 likes
    Beneteau 361
    US 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.
     


    BrianRobin likes this.
  12. BigEasy

    BigEasy

    Joined Jun 21, 2004
    1,115 posts, 289 likes
    Beneteau 343
    US Slidell, LA
    Rich,
    Good luck; hope it all works out!
     


  13. Mechone

    Mechone

    Joined Mar 20, 2016
    163 posts, 40 likes
    Beneteau 351
    ca WYC Whitby
    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
     


  14. Mechone

    Mechone

    Joined Mar 20, 2016
    163 posts, 40 likes
    Beneteau 351
    ca 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
     


    BigEasy likes this.
  15. BigEasy

    BigEasy

    Joined Jun 21, 2004
    1,115 posts, 289 likes
    Beneteau 343
    US 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?
     


  16. Mechone

    Mechone

    Joined Mar 20, 2016
    163 posts, 40 likes
    Beneteau 351
    ca 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.
     


  17. Alfa

    Alfa

    Joined Mar 19, 2015
    16 posts, 2 likes
    Beneteau 31
    Ca 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).
     

    Attached Files:



    Mechone likes this.
  18. Alfa

    Alfa

    Joined Mar 19, 2015
    16 posts, 2 likes
    Beneteau 31
    Ca 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.
     


  19. richpinto72

    richpinto72

    Joined Feb 21, 2009
    10 posts, 1 likes
    Beneteau 361
    US Sag Harbor
    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
     


  20. Alfa

    Alfa

    Joined Mar 19, 2015
    16 posts, 2 likes
    Beneteau 31
    Ca 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.
     




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