Prop steer

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Prop steer

Postby dustoff135 » Wed Jul 30, 2008 12:30 pm

I realize this may sound a little crazy, but I believe an issue like this was addressed before here on the Buzz.

I took my newly refurbished XK19 out for the first time on Sunday. All went well except for a steering issue. When going from a standstill to full throttle the boat jerked to port and did not respond to steering input. I thought something had broken in the steering. I shut the boat off and had a friend turn the wheel and everything appeared fine at the outdrive. We pressed on. Later, I slowly increased the engine to full throttle and had to hold the steering full right in order to track straight.

I've been told that this is probably due to the trim tab incorrectly set on the Volvo Penta 250 Outdrive. It is essentially in line with the centerline of the boat currently.

Has anyone else encountered something similar? If so, how should the tab be set? Which way does it need to turn in order to be the most efective?

Patrick
Patrick

Previous projects: 1940 17' Barrelback, #71572
1971 XK19, ORCZ19-2016V

New project: Looking???
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easy

Postby Peter XK19 » Wed Jul 30, 2008 2:24 pm

hey, thats an easy problem to solve, think of the tab as a mini rudder(which it basicaly is) If your boat goes in one direction ajust the tab in the counter direction.

If you get a non feedback steering system you dont need any trim tab. And your boat will go faster and drink less gas. :)

Peter
www.xk19.com
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Postby 57 chris » Wed Jul 30, 2008 3:59 pm

Hi Patrick,
You are experiencing a very normal phenomenon that is very easy to correct, The little tab under the anti-cavitation plate above and behind the prop is adjustable (look for an allen head bolt head on the top of the anti-cav plate near the aft end). You can adjust this while in the water by simply raising the drive after each test run. Just loosten this bolt and turn the tab about 10 degrees one way or the other and retighten the bolt and test run to see if the problem is better or worse. If the problem is worse then you turned the tab the wrong way. Once you have determined that you are turning the tab the correct direction, then continue adjusting until you can let go of the wheel at speed and the boat runs straight without the steering wheel turning in your hand.

Craig
1957 18' SeaSkiff #SK 18675 "Knot Sure!"
1958 18' SeaSkiff #SK18722 "Wreckreation"

Past projects: 1972 19' Lancer with 307 Volvo drive-Great Blue, 1968 23' Lancer Offshore with 283 Volvo drive-Narwahl
1988 FourWinns 245 Vista - Blue Ayes.

It's good to have wood!
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Postby dustoff135 » Wed Jul 30, 2008 4:42 pm

Thanks guys, I was hoping that this was the most likely cause. It scared the crap out of my wife, and certainly caught me off guard when this happened.

Patrick
Patrick

Previous projects: 1940 17' Barrelback, #71572
1971 XK19, ORCZ19-2016V

New project: Looking???
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Location: Smyrna, GA

Postby Wood Commander » Wed Jul 30, 2008 8:51 pm

I had exactly the same thing happen to me with my 19' Lancer. This was right after I installed a new no- feedback helm system that has some brake effect on the steering that is supposed to cancel slop and etc.
I thought if that little tab was straightened up, the boat would probably run a little faster, and the new steering system would compensate. Bad move! It did exactly what happened to you. I restored the original adjustment to the fin and all was well. If I remember correctly it was an adjustment to the left. The tab is there to compensate for the torque of the engine and the prop walk.

That Lancer had a 185 hp. Chevy/Chris Craft 283 F (FLV) and a Volvo 280 outdrive which has the large horizontal whale tail fins where the exhaust exits and just a thin vertical adjustable blade tab.

The 250 Volvo is different with a much narrower horizontal fin and a triangle shaped "torque blade" that has the engine exhaust coming out of it instead of the horizintal fin are like on the 280. Evidently it still functions in much the same way though.
Bret

1953 35' Commander "Adonis III"

1970 23' lancer project
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hm.......

Postby Peter XK19 » Thu Jul 31, 2008 12:28 am

Hey wood commander;
Your non feed back system has had to be giving some feed back. Look at all racing drives, they never have trim tabs!
Anyone who has experienced these problems can easily understand the great importance of heavy duty installment when mounting your steering system to the transom.

Peter
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