Re: Belt drive
- And where do you find an air powered starter?!
--- In AtkinBoats@yahoogroups.com, "oldbingey" <bingey@r...> wrote:
> Dear Rob,
> I appreciate your compliments and know who you are so that makes
> them have some real significance.
> I'll answer those questions real quick because I am fixing to head
> back to the coast to batten down for this next damned hurricane.
> 1. I turned the phenolic disc from a piece of 12"x12"x1" sheet
> McMaster Carr. I don't remember what it cost but it wasn't too
> much and I was able to make some replacement sheaves out of the
> scraps. The rubber tire that contacted it to give reverse was the
> transmission drive wheel out of a Snapper riding lawn mower... $10.
> 2. The air spring is a miniature of the air springs on a semi
> truck and is called an "air spring" in McMaster Carr.
> 3. The single drive belt is a sixteen groove belt about as big
> around as my hat band (and some say I have a case of the big
> The brand name is "PolyVee."
> 4. The thrust bearing is a regular farm duty flange block with a
> one inch ID ball bearing. Both it and the belt have run for more
> than 2,500 hours so far.
> It is a good transmission. I'll list some of the advantages:
> 1. It is much lighter than even a Hurth.
> 2. It runs almost without friction... no heat build up... no
> transmission oil cooler.
> 3. The shaft runs in its own bearings attached in rigid alignment
> to the hull of the boat and does not wiggle with the engine so the
> stuffing box stays adjusted and does not leak at all. I assume the
> cutless bearings will last longer, too.
> 4. It is cheap.
> 5. It runs quiet (silent).
> 6. It works on an engine without a heavy bellhousing... an
> automotive engine without any "marine" adaptations.
> I have figured out how to put the air spring back on there so that
> it won't rattle around but I have to take the boat out of service
> do the modifications and I can't do that right now. It runs almost
> every day. I'll write up the details in MAIB to the point of
> I also like that Normand stern on Shoals Runner. I don't know which
> would be the better boat but I assume that there is a progression
> and Shoals Runner was designed later.
> I don't know anything about chine style boats so I can't comment
> about the difference in the chine angle of the two boats.
> My boat is way lighter than the Atkin boat.
> I am looking forward to reading about your project in "Duckworks."
> Good luck,
> Robb White.
> --- In AtkinBoats@yahoogroups.com, "robrohdeszudy"
> <robrohdeszudy@y...> wrote:
> > Hey Mr. White. Just found this post. Your "tranmission" is
> > A couple questions:
> > 1. Where'd you get the phenolic disk? What should I look for.
> > 2. Air spring? Like in a pickup truck?
> > 3. What size and number of belts did you use?
> > 4. What thrust bearings did you use?
> > I'm excited about homebrewed marine transmission!
> > Many thanks,
> > --Rob
> > --- In AtkinBoats@yahoogroups.com, "oldbingey" <bingey@r...>
> > >
> > > The propeller of my outlaw Rescue Minor is belt drive using one
> > > those poly-vee belts like on modern cars. That allowed me to
> > > the reduction needed (4 to 3) at the shaft to turn Atkin's
> > > recommended propeller with the 3,600 rpm Kubota engine. The
> > > propeller shaft carries the thrust bearing. I described the
> > complete
> > > machinery setup in a bunch of articles in "Messing about in
> > > but I'll briefly list the peculiarities: The engine is a 20
> > > ($1,300 at the time) three cylinder tractor engine which was
> > > purchased without a bellhousing. The weight was 134 pounds in
> > that
> > > configuration. The engine is cooled by a flat plate copper
> > > cooler flush with the bottom of Atkin's "box keel." The
> > is
> > > raw water cooled by a "Shur Flo" diaphragm pump adapted to
> > > directly off the camshaft of the engine. The exhaust manifold
> > > wrapped with copper tubing in which the exhaust water flows.
> > > minimize the overhanging load on the crankshaft from the belt
> > > tension, there is a spring loaded tensioner between the output
> > shaft
> > > of the engine and the propeller shaft. I had an air spring in
> > there
> > > originally so that I could have neutral and reverse by pivoting
> > > rear of the engine up and down with a foot operated lever to
> > > the belt for neutral and then, by further depressing the pedal,
> > > cause a rubber tire attached to the belt drive sheave to
> > > phenolic disc attached to the driven sheave. Initial
> > > the pedal released the pressure on the air spring and releasing
> > > pedal allowed the pressure to build back up and re-tension the
> > > belt. The air came from a small electric compressor which
> > > blows the horn. I intended to rig an engine driven compressor
> > > air start the engine so I could completely eliminate the
> > > system but I never got around to it. The wiggling of the
> > > its soft motor mounts eventually (after about 800 hours) wore
> > enough
> > > slack in the air spring rig so that it started clattering so I
> > > removed it and made the spring belt tensioner I have on there
> > > I never used the reverse or neutral anyway. The boat will
> > > its own length at idle. It has proven to be a quiet and
> > > free rig.
> > >
> > > Robb White