Boat pulls to Starboard under power
Printed From: myHanse.com
Category: Hints & Tips
Forum Name: 370 / 375
Forum Description: 370 / 375 Hints, Tips and News
URL: https://www.myhanse.com/forum_posts.asp?TID=12195
Printed Date: 27 March 2026 at 03:41
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Topic: Boat pulls to Starboard under power
Posted By: Pride of Waterford
Subject: Boat pulls to Starboard under power
Date Posted: 07 September 2020 at 16:53
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On our 2008 370 we have a yanmar SD20 saildrive and flexofold 2 blade prop. Recently we had a blip with the autopilot turning off and the boat suddenly veered to Starboard. We continued testing and found that under almost any power the boat pulls strongly to starboard. Any ideas, or is this normal?? Thanks ------------- Brod Port Lairge |
Replies:
Posted By: andrewlambert
Date Posted: 07 September 2020 at 17:58
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I have a 370 from 2007 same engine and sd20 - I also get a slight pull but to port, thewheel if let go gradually turns to port - my theory is the prop wash is hitting the balanced rudder in slightly unequal amounts I think this because the boat is perfectly bacalnced when sailing and if you look at the distance from prop to rudder it only takes a very slight angle to make noticeable impact on the rudder , also the fact that mine slightly veers to port and yours to starboard ? Might further confirm the theory Of prop wash hitting the rudder Tbh it could be noNsense but I can’t think of other reasons given the perfect balance under sail I intended to research some other forums etc to see if any other boats with similar set up experienc e the same ------------- Hanse 370 #237 "Ginger Bay" UK, River Hamble |
Posted By: andrewlambert
Date Posted: 07 September 2020 at 18:00
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ps the pull to port I get is very very slight can be managed with one finger on the wheel ------------- Hanse 370 #237 "Ginger Bay" UK, River Hamble |
Posted By: andrewlambert
Date Posted: 07 September 2020 at 18:07
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https://jeanneau.proboards.com/thread/8309/rudder-moves-when-motoring" rel="nofollow - https://jeanneau.proboards.com/thread/8309/rudder-moves-when-motoring Well after a little googling some interesting possibilities - good thread above - sail drive and shaft owners with some thoughts ! To me it sounds like We may not have an issue generally however yours as you say is strong in force I have a fixed prop not folding I wonder if that has any impact in your case ------------- Hanse 370 #237 "Ginger Bay" UK, River Hamble |
Posted By: samuel
Date Posted: 07 September 2020 at 18:13
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On my boat the pull to one side increases significantly as the coppercoat begins to foul. This is, presumably, due to the increased load on the prop, thus causing a greater reaction to prop wash. I also notice the stern digging in a little, as I have to use more throttle to compenate loss of speed. ------------- Daydream Believer- Hanse 311- No GBR9917T- Bradwell Essex |
Posted By: Mschesser
Date Posted: 16 September 2020 at 03:07
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I also own a 2008 370 configured the same that will also veer to starboard under power, but is perfectly balanced under sail. Imbalance in the prop wash under power is certainly the cause ------------- M Chesser, 370, “Red Sky” |
Posted By: astarte
Date Posted: 16 September 2020 at 12:11
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Hi. You should differentiate between prop wash and prop walk. The latter comes from the rotation of the propeller. In my 370 with SD50 the propeller rotates towards left when in forward resulting in the boat turns to starboard. Prop walk and prop wash is of course beneficial when turning the boat without thruster in confined areas ------------- Kristoffer Hanse 370e #412 |
Posted By: andrewlambert
Date Posted: 16 September 2020 at 20:21
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Astarte You are right on propwalk vs propwash This discussion has helped me work out my slight pull is due to prop walk Great point 👍 ------------- Hanse 370 #237 "Ginger Bay" UK, River Hamble |
Posted By: Captain MJ
Date Posted: 18 September 2020 at 04:50
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Indeed it is perfectly normal... and it is caused by prop walk. Fair winds! -Cpt. Mark ------------- Mark Jordan : ASA Sailing Instructor : USCG Licensed Captain : Hanse 342 "Twelve-Winded Sky" #405 |
Posted By: Pride of Waterford
Date Posted: 13 October 2020 at 17:09
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Many thanks for you reply. Is the pull under power to starboard very big? Like yours she is balanced under sail. Is there anything we can do to improve this? Thanks Jon ------------- Brod Port Lairge |
Posted By: Sea-U
Date Posted: 14 October 2020 at 07:11
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Nothing to do. You need same distance from propeller to hull as from propeller to bottom :-) -------------  Sea-U is a 370e #532 located SW Norway
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