Author Topic: is prop walk possible with sail drive  (Read 642 times)

aquapore

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is prop walk possible with sail drive
« on: January 11 2019, 11:39 »
I understand that prop walk relies on the close proximity of the prop to the hull.
With a sail drive that distance is considerably more that with a straight through shaft driven prop.
I have been experimenting with my bav 41 Volvo Penta sail drive and find essentially no prop walk effect.

Am I doing something wrong or is the physics defeating me.

Would appreciate comment.

Regards

Aquapore

Symphony

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Re: is prop walk possible with sail drive
« Reply #1 on: January 11 2019, 13:33 »
There are many factors that affect prop walk, and saildrives either reduce or eliminate most the effects. The distance between the hull and the prop is one of them as is the fact that the thrust from the prop is horizontal rather than at a down angle. The prop walk is still there and you can provoke it with bursts of power at very low speeds, but in normal use its effects are reduced for the above reasons.

Craig

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Re: is prop walk possible with sail drive
« Reply #2 on: January 11 2019, 22:08 »
Prop walk is also reduced by the proximity of the sail drive to the centre of turning moment ( keel) and is affected by the shape of the hull near the prop. A heavily fouled prop will also increase prop walk.

On boats with sail drive ( including most modern Bavarias) this means that prop walk is negligible.

The only time I see any prop walk on my Bavaria 38 (2010) is when I engage reverse gear while still moving forward. In these circumstances I get up to a 30 degree turn before the rudder takes control.

Craig
" Shirley Valentine"
Gold Coast
Australia

Club 56

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Re: is prop walk possible with sail drive
« Reply #3 on: January 12 2019, 08:48 »
Hi Craig

Always wondered how other models went with prop walk. My Vision 42 ( 2013 model ) has a lot of prop walk. Came fitted with the Volvo folding prop and the 55 HP motor.

A mate has the 2010 Vision 40 and is much better than ours.

Comments welcome.

Cheers Club 56

simonmoore

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Re: is prop walk possible with sail drive
« Reply #4 on: January 12 2019, 20:33 »
Hello, I get a good amount on our 2003 Bavaria 38.  The sail drive is fitted with a fixed, three bladed propellor and as soon as I go astern when stationary the bow goes to port and the stern to starboard. 

Yngmar

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Re: is prop walk possible with sail drive
« Reply #5 on: January 13 2019, 11:21 »
Hello, I get a good amount on our 2003 Bavaria 38.  The sail drive is fitted with a fixed, three bladed propellor and as soon as I go astern when stationary the bow goes to port and the stern to starboard.

Same with our 40 Ocean from 2001.
Sailing Songbird (Blog & YouTube)  ⛵️ Bavaria 40 Ocean (2001)

MarkTheBike

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Re: is prop walk possible with sail drive
« Reply #6 on: January 14 2019, 22:28 »
Same for me with a 2030, fixed 2-blade. Have come close to scraping 42' neighbour when backing out of our marina berth (this is 12m wide between the two fingers). Coming to a stop is fine though, no problems at all, and reversing itself is a joy. Just the zero to backwards bit...
ATB

Mark

Kibo

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Re: is prop walk possible with sail drive
« Reply #7 on: January 18 2019, 17:20 »
Vision 46 with fixed 3 blade original prop.

I never notice any significant prop walk and am more concerned with windage since the Vision series is quite susceptible to cross winds being fairly slab sided and with high freeboard.
Ian
SV Kibo, 2014 Bavaria Vision 46