When I'm motoring, in reasonably calm seas, my Tach at 6 knots is about 1700 rpm's.
I think this is a bit low, but not sure.
At 2000 rpms sounds like it is working too hard!
Is this accurate?
Thanks
Rich
—
Rich
Richard & Joan Bain
PAZZO Hull#1670
1997 Catalina 36 MK11
Bayfield, Ontario
My Day Job Below
www.richardbain.com
www.bineapress.com
Rich, I suspect it reads way low.
There is an article in the C36IA Maintenance library about how to check and adjust the tach. I recently purchased an optical tach at Frys (or was it Harbor Freight...I forget) and it set me back about $60 or so, so maybe that is a solution for you. Alternatively, you could use a flourescent lamp to sync the crankshaft pulley, as the 60 Hertz alternating current of the US/Canada public power system creates a 120 per second reference source.
Larry Brandt
S/V High Flight #2109
Pacific Northwest, PDX-based
2002 C-36 mkII SR/FK M35B
I just checked ours this weekend, it reads 50 rpm low all the way up but that is pretty acceptable I think. In flat water at 2100 rpm we get 6 knots, that is down .2 knots since changing bottom paints from VC17 to a soft ablative. That is with a 15 X 11 (stamped on the hub) 2 bladed fixed prop. The sweet spot for our engine seems to be 2100, it just smooths out and runs nicely at that. Below that a bit more vibration, much above 2400 it starts to sound too frantic and little speed is gained.
BTW, I got an optical tach from DealExtreme.com for 14 bucks. It is exactly the same model that a well known automotive store sells for 70 bucks.
It is amazing how cheaply you can get an optical tach and infrared temperature gun these days. They are nice to have even if used infrequently.
Duane Ising - Past Commodore (2011-2012)
s/v Diva Di
1999 Catalina 36 Hull #1777
Std rig; wing keel, M35B, Delta (45#)
Punta Gorda, FL
http://www.sailblogs.com/member/diva-di/
You should be able to check it even without an optical tach. Run the engine out of gear to WOT. What's it read? Depending on your engine, should be around 3000 RPM. Do the same in gear. Is it different? How much?
On our M25, the engine is rated 3000 RPM WOT and I can get to that both in gear (just barely) and out of gear.
This is an initial check to see if your tach is anywhere near normal.
Report back or buy an optical tach.
Teleflex has good instructions on how to adjust their tachs on their website.
Stu Jackson, C34IA Secretary, C34 #224, 1986, SR/FK, M25 engine, Rocna 10 (22#)
...or you could borrow the C-36 association optical tack from the "toolbox". Just fill out the request form and it is sent to you within a few days!
Stephen Kruse
Kruse Control #1428
1995 C-36 MKII SR/WK
Lake Lanier, Ga.
Of course, there's the other issue: Is your knotmeter accurate?
Larry Brandt
S/V High Flight #2109
Pacific Northwest, PDX-based
2002 C-36 mkII SR/FK M35B
FWIW, I calibrated my tach when I installed my Balmar alternator and I make ~5.8 knots, calm water, @ 2000 rpm. This is with a 2-blade Max Prop.
Wally
"Onanne"
2000 MKII, deep keel, tall rig
Lake Champlain