[Public-List] Cracked Stern Tube - Laugh or Cry?
Hernán Scarnichia
hernanscar at gmail.com
Mon Sep 24 10:23:15 PDT 2018
I did it with just a few small differences
I calculated the length of tube needed to allow space for stuffing box and
propeller and cut it before installing. I think I left it a bit long on the
outside, but not on the inside, not very comfortable to work in there...
To align the tube I used a 7/8 wooden dowel as a shaft (the real shaft and
coupler was in the machine shop) I used the cutless bearing on one end and
masking tape wrapped on the dowel on the other end to center the tube. I
don't remember how I attached the dowel to the transmission coupler so it
would stay centered, there was duct tape involved.
Then glued the tube to the hull with epoxy: I drilled two small holes on
the sides of the hull to inject epoxy into the small gap between the tube
and hull, then injected epoxy until it was oozing front and back all around
the tube, once that epoxy was cured I removed the cutless bearing and the
shaft and applied a few layers of cloth inside and out (grind a tapered
hollow on outside before)
I also removed the engine to get better access, I needed to get in there
with a grinder and a few sanding disks and wire brushes to clean up and
make sure the new fiberglass would stick. then I put the engine back to
align, then took it off again to fiberglass, and then on again. made a
crate for it so it could sit on the cabin floor.
I did not use polysulfide between the cutless bearing and the tube, I used
epoxy and a mold release wax on the bearing, then the setscrews. the
clearance between bearing and tube was pretty tight to begin with.
I used a 1 foot long 2"od x 1.5"id fiberglass tube
On Sun, Sep 23, 2018 at 2:33 AM Jonathan Bresler <262alberg30 at gmail.com>
wrote:
> Wondering about replacing the original stern tube with a fiberglass one.
> Might the steps be as follows? Anything missing? Any misunderstandings?
> Advantages vs disadvantages of fiberglass over the original?
>
> Install fiberglass stern tube
>
> - Remove wad of material inside the boat around the stern tube
> - Remove existing stern tube
> - Remove propeller
> - Remove existing cutlass bearing housing
> - Buy replacement cutlass bearing
> - Buy fiberglass stern tube with large enough internal diameter to
> house the cutlass bearing and long enough to reach engine
> - Enlarge hole in deadwood to take the new fiberglass stern tube
> - Cut fiberglass stern tube to fit from engine to somewhat outside boat
> - Insert spare cutlass bearing into one end of fiberglass stern tube
> - Insert new cutlass bearing into the other end
> - Drill holes in either side of the fiberglass stern tube for set
> screws to hold the cutlass bearing in the deadwood
> - Slide stern tube into place so that one end is nearly touching the
> shaft coupling and the other protrudes out of the deadwood
> - Align engine to stern tube and cutlass bearings
> - Fiberglass the fiberglass stern tube into place
> - Pull propeller shaft
> - Cut fiberglass stern tube to allow space for the stuffing box
> - Remove cutlass bearings from fiberglass stern tube
> - Polysulfide and set screw cutlass bearing into fiberglass stern tube
> - Install stuffing box onto fiberglass stern tube
> - Install propeller shaft
> - Check alignment and re-align if needed
> - Done
> -
> - about half way down
> http://www.lackeysailing.com/archived/hattiemae/june09/62209.htm
> - bottom paragraphs of
> http://www.lackeysailing.com/archived/hattiemae/june09/62309.htm
> - first half of
> http://www.lackeysailing.com/archived/hattiemae/june09/62409.htm
> - middle of
> http://www.lackeysailing.com/archived/hattiemae/june09/63009.htm
> - lower portion of
> http://www.lackeysailing.com/archived/hattiemae/july09/70209.htm
> - top half of
> http://www.lackeysailing.com/archived/hattiemae/july09/70309.htm
>
> Jonathan
>
> On Wed, Sep 19, 2018 at 1:15 PM, Gordon Laco via Public-List <
> public-list at lists.alberg30.org> wrote:
>
>> Understood… but it’s quite secure…
>>
>>
>> Gordon Laco
>> www.gordonlaco.com
>>
>>
>>
>>
>> > On Sep 19, 2018, at 12:56 PM, Hernán Scarnichia <hernanscar at gmail.com>
>> wrote:
>> >
>> > Gord,
>> > yes that would have been another way to fix it.
>> > probably easier.
>> > at that time I didn't trust that a bolt threaded on epoxy could
>> withstand any shaft vibration.
>> >
>> > On Tue, Sep 18, 2018 at 10:29 PM Gordon Laco via Public-List <
>> public-list at lists.alberg30.org <mailto:public-list at lists.alberg30.org>>
>> wrote:
>> > Hello Hernan
>> >
>> > Those bolts are normally threaded in as you describe. They cannot be
>> bolts through. You can restore their integrity if you need to by filling
>> the loose bolts hole with thickened epoxy, then redrilling and tapping new
>> threads.
>> >
>> > Gord
>> > 426 Surprise
>> >
>> > Sent from my iPhone
>> >
>> > > On Sep 18, 2018, at 10:35 PM, George Dinwiddie via Public-List <
>> public-list at lists.alberg30.org <mailto:public-list at lists.alberg30.org>>
>> wrote:
>> > >
>> > > Hernán,
>> > >
>> > > How did a fiberglass shaft log change the bolts of the cutless
>> bearing housing?
>> > >
>> > > - George
>> > >
>> > >> On 9/18/18 1:30 PM, Hernán Scarnichia via Public-List wrote:
>> > >> The problem on my boat (#414) was that the two bolts holding the
>> cutlass
>> > >> bearing housing were not through bolted, just threaded into the
>> fiberglass,
>> > >> these were not lag bolts with a coarse thread either, just regular
>> thread
>> > >> bolts threaded straight to the fiberglass. The shaft vibrations
>> loosened
>> > >> them and one bolt was already gone when I hauled out.
>> > >> I suppose that if I had realized earlier that the engine was
>> misaligned,
>> > >> and the shaft vibrating, it could all have been prevented.
>> > >> Either way I did not like the fact that all that was keeping the
>> water out
>> > >> was those two bolts and a wad of caulk so I scrapped the whole thing
>> and
>> > >> installed a fiberglass shaft log.
>> > >> On Mon, Sep 17, 2018 at 1:58 PM George Dinwiddie via Public-List <
>> > >> public-list at lists.alberg30.org <mailto:
>> public-list at lists.alberg30.org>> wrote:
>> > >>> On 9/17/18 5:36 PM, Jonathan Bresler via Public-List wrote:
>> > >>>> Remember hearing form various sources that cutlass bearings and
>> the rest
>> > >>>> are tricky
>> > >>>> "cause the stern tube might turn or twist and break its bond to the
>> > >>>> deadwood".
>> > >>>> Seems that won't be a problem in this Triton given the amount of
>> epoxy
>> > >>>> applied.
>> > >>>
>> > >>> This was my fear, and the reason I pulled and rebedded the stern
>> tube
>> > >>> when I noticed that it had turned. The hose clamp screws were no
>> longer
>> > >>> pointed up where a screwdriver could reach them.
>> > >>>
>> > >>> It turned out that this is an unnecessary worry. The water is
>> contained
>> > >>> by the cutless bearing housing (and bolts), and the stuffing box.
>> The
>> > >>> caulking of the stern tube itself is not critical.
>> > >>>
>> > >>> - George
>> > >>>
>> > >>> --
>> > >>>
>> ----------------------------------------------------------------------
>> > >>> When I remember bygone days George
>> Dinwiddie
>> > >>> I think how evening follows morn;
>> gdinwiddie at alberg30.org <mailto:gdinwiddie at alberg30.org>
>> > >>> So many I loved were not yet dead,
>> http://www.Alberg30.org <http://www.alberg30.org/>
>> > >>> So many I love were not yet born. also
>> see:
>> > >>> 'The Middle' by Ogden Nash
>> http://idiacomputing.com <http://idiacomputing.com/>
>> > >>>
>> ----------------------------------------------------------------------
>> > >>>
>> > >>>
>> > >>>
>> > >>> _______________________________________________
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>> > > --
>> > > ----------------------------------------------------------------------
>> > > When I remember bygone days George Dinwiddie
>> > > I think how evening follows morn; gdinwiddie at alberg30.org
>> <mailto:gdinwiddie at alberg30.org>
>> > > So many I loved were not yet dead, http://www.Alberg30.org
>> <http://www.alberg30.org/>
>> > > So many I love were not yet born. also see:
>> > > 'The Middle' by Ogden Nash http://idiacomputing.com
>> <http://idiacomputing.com/>
>> > > ----------------------------------------------------------------------
>> > >
>> > >
>> > >
>> > > _______________________________________________
>> > > These businesses support your Association:
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>> > _______________________________________________
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>
>
>
> --
> Jonathan M Bresler
> S/V Constance Alberg 30 #262
> Annapolis/Eastport MD
>
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