torque steer

Byrdman · Posted: Fri Apr 16, 2010 6:39 am Post subject:

I bought a very inexpensive inclinometer at West Marine and mounted it on the dash of C-Byrd and loved it. It took the guess work out of "am I running flat". Now, I see they have some snazzy digital assist (digital read out rather than just the bubble in the level) available, for less than $30. I do not recall ever having an issue with not being able to clearly see the bubble on the one I had. If for nothing else, it made sure on cruises that I was running true, which, for sure increased my fuel efficiency. I really liked it.

Link: http://cgi.ebay.com/Digital-Inclinometer-Angle-Meter-Gauge-Spirit-Level_W0QQitemZ200460306651QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item2eac5d88db

Larry is on target with what my late Father use to tell me in our boats with old cable steering.... "Tilt the motor up or down until it has neutral pull or until you can let go of the wheel and the boat still remain on a straight course." A different angle for different speeds was noted....and, it just felt better on your arms, particularly if you had a beverage in one of your hands.

rjmcnabb · Posted: Fri Apr 16, 2010 11:02 am Post subject:

Larry H. and Byrdman,
Both of you are talking about the Asymmetric Disk Effect on the props, which is different than prop-walk. Prop-walk is always there, although it makes itself most known at low speeds. ASD (pilots call it P-factor) is a function of the angle at which water flow intersects the disk of the spinning prop, and goes to zero when the disk is at right angles to the flow. So, with an O/B or I/O, you can get up on plane at a speed you want and then change engine trim to dial it out. That is how I've handled NoddyBleu: get her up on plane and reduce the trim tabs until I maximize the MPG (from the Honda fuel management system) while keeping the boat pretty level, port & starboard. Once there, I adjust the trim so that the boat will hold a course without hands on the wheel. At that point I assume that the propshaft is parallel to the surface of the water, even though the boat is slightly bow-up. MPG may have improved some more. After that, only minor adjustments may be necessary: to compensate for waves, for when I cross a wrack line, or for other variables of wind and current. I think that these principles would apply to twin engines, but might be a little more nuanced, especially on big set-ups where the props are counter-rotating.
(I keep a six inch bubble level lying on the centre dash; it also should be useful for fore & aft trim, but the dash is not level -- even at rest -- and I haven't worked that part out, yet. I sold NoddyBleu last week, so I may never work it out.) This is fun stuff! Smile

Rod

hardee

lloyds,

Sorry I am confused here but your profile says you have a 16 with a single 50. So, is this an issue with the 16, and did you repower to the 35's?

jennykatz · Posted: Sun Apr 18, 2010 9:18 am Post subject: torgue steer

When we had our Duck c-22 with 90hp Suzuki with a 14/18 prop the torgue was unbelievable you had to have the trim on 4out of 5 to get it to steer properly. If you want to get away from the torgue steering problem install hydraulic steering . With our cape cruiser (venture23) witha F-115 with hydraulic steering no problems .