Bearings

[Dallinson]

Tony
Looking at the photos of the paddle drive arrangement it struck me that
possibly ball bearings would work well on the inboard end where you need a
bit of tension for the belts to grip. The first time I made the engine room
of the Scotia I used brass bearings, but found that there was quite a lot of
friction and I changed them for ball bearings with a huge improvement. I
bought the 5mm ones at my local model car shop. Using the oiler tubes is
good idea and should prevent the water creeping in, even if she rolls more
than she should!!
If anyone needs a supplier of all types of small roller/ball bearings,
there is a place that professes to be able to supply anything in that line.
It is a company called Arc Euro Trade. Fax number 0116 269 5805 Tel 0116 269
5693. Send them an E-mail, address arceurotrade@btopenworld.com
Usual disclaimers.
Happy paddling
David

[Tony Mattson]

Hi David,

what a good idea. And blindingly obvious in hindsight! I walk in your
shadow, sir!

Re the oiler tubes, these came into being after my mate Les Bryant
said to me the other day that all we're doing is turning boat
propulsion on its side. In an all too rare flash of insight I did
exactly that - made two prop shafts and turned them sideways. So in
effect I've got a stern stuffing gland coming out each side of the
boat.

I saw a nice alternative the other day, which was a slim brass box
attached inside the boat to the side of the hull, open at the top and
set both sides with bronze bearings. The brass box was a receptacle
for a piece of oiled felt with a small hole in the centre that the
paddle shaft went through.

many kind regards
Tony

[Dallinson]

Tony.
I think that the combination of the oiler tubes bonded to the sides of the
hull to keep the water out and a ball bearing to take the side forces
imposed by the belt (not usually present in conventional prop driven boat)
is probably the best of all worlds. There is of course also some side thrust
at the outboard end (which pushes the boat along!!) but it doesn't seem to
be as great as at the belt end.
I hardly need to say that it doesn't seem to take much friction in the drive
train to eat up battery life very quickly.
Good luck with the rest of your project. The funnel should be a real "smoke
stack" in operation. I shouldn't wonder but complaints to chief engineer to
get some decent coal, will soon be the order of the day!!
Please post some more pics when, and as, you progress.
Incidentally looking in the first album of the Armenia, there is a beautiful
looking boat and I wondering what the latest on that project is? There are
no added details.
Good luck to all.
David.

[Tony Mattson]

David,

I've taken up your suggestion and have managed to pick up a four pack
of sealed ball-race bearings originally destined for an R/C car, 5mm
internal dia. 8mm external dia.

The internal dia is perfect for my stainless shafts which run to
4.9mm, giving around 4 thousands of an inch tolerance. (tut, tut,
mixing metric and imperial again!)

The 8mm external dia is identical to the external dia of my oiler
tubes and also to the internal dia of the next size up brass tube to
the oiler tube I used. The bearings fit snugly into this larger tube
with a moderate gentle press fit.

The thickness of the bearings is 3mm.

So this weekend I'll use the larger tube to bodge up outer sleeves
or 'cuffs' which will extend 3mm beyond the ends of my oiler tubes.
This will create snug seatings for my wonderful new bearings. Seeing
I have four bearings I'm thinking to do this at both ends of the
oiler tubes, inboard and outboard. Potential friction problem
eliminated!

And with the bearings being sealed, the potential for water entry
should be minimal.

Thanks to your suggestion I'm sleeping at night again! Will post a
photo shortly.

My goodness I'm glad I found Paddleducks - this group has such a
wealth of knowledge and good ideas it should be packaged and retailed!

Thank you again.

Kind regards to all
Tony

[Derek Warner]

on Friday, November 14, 2003 1:56 PM, Tony Mattson said :
--------------------------------------------------------------------------------

David - I've taken up your suggestion and have managed to pick up a four pack
of sealed ball-race bearings - The internal dia is perfect for my stainless
shafts which run to 4.9mm, giving around 4 thousands of an inch tolerance
------------------------------------------------------------------------------

Hi Tony - yes you only have to look back at the archives - David has provided a wealth of critical advice to
many newer PD's in earlier days [me included]
------------------------------------------------------------------------------

With the 0.0039" between the ID of the ball bearings & the OD of the stainless shaft, LOCTITE proprietry
bearing mount Type 641 [has gap filling properties] would be ideal [tip is to get a 4.0 mm ID nitrile o-ring,
roll that on to the shaft with the shaft in the vertical plane, drop the ball race down onto the o-ring & position
the ball race in the correct location - add a few drops of 641 & that small volume will cure & be retained
between the shaft & race & will not drip out due to the o-ring which can later be cut away if required]

You have noted that the bearing OD will technically be a transition [press] fit, however the light gauge or
wall thickness of the brass tube will expand when the bearings are installed - no problem after
installation of the bearings just a few drops of the same Type 641 through the oiler point & then let cure
in each vertical plane etc - LOCTITE would be acceptable for joining the K&S type brass telescopic next
size up turbing, however I still prefer to soft solder here if possible - regards Derek

[Tony Mattson]

Done and dusted. Before and after shots are posted in my photos and
the originals are now securely installed.

We've achieved a huge reduction in friction, gentlemen. Many thanks
to you all for your support.

I've also posted a painting of PS Britannia, one of my long
term 'best intentions'. She was a double ender of around 119 ft. You
can just make out the wheel at the "other end", left of the last
three passengers. Wld appreciate any and all advice re potential
pitfalls and issues. Stablility and windage strike me immediately.

Kind regards to all
Tony
Auckland, NZ

[Dallinson]

Tony.
Looks good to me!! In fact your whole driven train looks very good with the
added advantage of being able to "tune" the speed of the paddles, as the
pulleys are so easy to change.
I used to visit Auckland, before the bridge, in the late 50s, very early
60s, as an engineer with the New Zealand Shipping Company. I saw many of the
old double ended ferries running across to Devonport, but unfortunately the
ones with paddles had long been replaced by then!!!
The PS Britannia has the paddle shaft (and relatively large heavy paddles)
set very high, so stability will definitely be a major consideration.
Possibly some extra, non scale, hull depth and some ballast will be most
beneficial.
Good luck, she looks a beautiful boat to model.
Regards
David