Hi Brent,

A bit belated, but here's all I've learned about BW Velvet Drive gears:

There were four models; two inline (Model #s 10-17 & 10-18; available ratios:
1.00, 1.52, 1.91, 2.10, 2.57, 2.91 : 1 ) and two (CR2) drop center (10-13 &
10-14; ratios: 1.58, 2.03, 2.47, 2.93 : 1).  The drop center versions are no
longer manufactured.  Velvet Drive Corp. (spun off from Borg-Warner in the
1990s) continues to build inline models (don't know if they're the same
ratios), but the drop centers are obsolete and "orphaned" (my word) in the
sense that no one is making parts for them.  The BW drop center gears
reportedly have a "drop" of about 1.5 inches from  the plane where the input
shaft goes in the housing to where the output shaft comes out.

There is a company in Ft. Lauderdale (Transmission Marine, Inc.) which does
repair and rebuild these gears.  I visited there recently and learned that
they do have rebuilt trannys in stock, which they sell on a sliding scale that
depends on the condition of the "core" you're trading in.  Briefly, the scale
can go as high as $8,000; with the top price for rebuilding a core that is
totally shot.  They have a limited number of parts manufactured for them
(primarily output shafts), but by and large they're using reconditioned used
parts to rebuild these gears.  Hence the importance of the condition of your
core in determining your price.  All of the foregoing figures are for complete
rebuilds, not lesser repairs.

My engine surveyor told me he thinks there's a company in the Washington
D.C./Maryland area that also rebuilds/repairs them, but he didn't know the
name.

Other alternatives I discussed with them included replacing them altogether
with other brand drop center type gears, or new Velvet Drive inline gears.
Prices ranged from $3,200 for a Twin Disc "drop type" plus $3,000 installation
(because the offset distance is different than that of the BW gear, thus
requiring repositioning of the engine and therefore its exhaust lines, control
cables, etc.), to $3,200 for a new inline Velvet Drive, again with similar
installation costs for repositioning the engine.  They recommended putting in
an inline if complete replacement is needed.  Please note that all of the
quotes were informal, NOT written, guaranteed estimates!

TMI's website is www.marinegears.com, and they're telephone number is (954)
467-1540.  (usual disclaimers)

So why, you may well ask, have I decided to go through with my purchase of an
Albin 43 equipped with drop center transmissions?  Because they also told me
that these gears, when mounted behind low power, slow turning engines such as
120HP Lehmans (my case) and properly cared for, will last a VERY long time.
They are strongly built and well engineered.  TMI's people advised me on what
to tell my engine surveyor to look for, and he had a few good ideas as well.
We worked them very hard in the sea trial, he listened to them with electronic
earphones, and checked them thoroughly, finally pronouncing them in good
shape..  The surveyor came very highly recommended by some people in this area
whose opinions I respect, so on Wednesday we close the deal.  Still scary,
even so.

One thing he did find though, was that the exhaust gas temps (EGT), not the
engines themselves, were a bit high under WOT (but not at lower RPMs) and he
felt that it was due to the boat being overpropped, which is why I was asking
about what props other Albin 43 owners are running.  This boat has 22x18s.
I've gotten some good answers, but still can't decide if it is overpropped or
not.

This is probably WAY more than you wanted to know, but I hope it helps!

Regards,

Nils

Overproping is simple.  If the engine can reach its
rated RPM at WOT, then the boat is not overpropped.
This test should ideally be done at normal cruising
displacement, with a bottom that is "average clean",
not just hauled, not covered in barnacles.

If the engine does not reach its rated RPM, then the
boat is somewhat overpropped.  Slight overpropping is
not a problem, especially if the boat is generously
powered, and will slightly improve fuel economy.
Pooh's John Deere 4039 is rated 80 hp at 2500.  With
my 2.8:1 trans and 26x21 3-bld prop, Pooh turns about
2300 rpm at wide open throttle.  I normally run
1600-1800 rpm, so this slight overpropping is no
problem.  If you normally run much closer to the
boat's actual max RPM, then overpropping is not a good idea.

=====
Mark Richter, M.E., aboard M/V Winnie the Pooh,
custom Morgan 46 Pilothouse Efficiency Trawler.
"Mark's Mobile Marine" electrical systems repair & consulting.  Homeport Stuart, FL

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