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Old 20 June 2021, 19:54   #1
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Ribeye leaning to Port when under power

Hi, just enjoying our recent purchase of a 2012 Ribeye 785s and have noticed that she is leaning over to port when under power regardless of tide/waves/wind conditions….so much so that the rear tube is bouncing in the water when we ride through slightly bigger waves. I have tried trimming right up and down and in between, but nothing seems to sort it. We have looked under the boat and cannot see any damage.

Is this to do with the propeller pitch or something else? I am a newbie so not experienced i am afraid. Thank you for any help.
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Old 20 June 2021, 19:56   #2
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Down to engine trim. Trim up at speed
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Old 20 June 2021, 20:33   #3
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Thank you

Thank you C2 Ribs. I will definitely make sure the engine is trimmed up when we are out this week.
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Old 20 June 2021, 20:51   #4
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I’ve had exactly the same problem as depdawg on a Humber ocean pro 6.3 150 and I’m very grateful that there appears to be an answe

[emoji106][emoji106]

Can you explain why this down to trim please?
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Old 21 June 2021, 06:00   #5
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Torque reaction of the hull from the prop when its trimmed in too far for the speed I believe.
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Old 21 June 2021, 13:33   #6
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If your RIB is sitting flat at rest and it's not a weight issue causing the port trim, I'd look at the skeg anode, usually there is a fin that you can trim to counteract the rotational force from the prop. As your prop rotates clockwise (going forwards) as well as providing forward thrust it also induces a rotational force. Excuse my very quickly drawn sketch but you'll see the point I'm trying to make. If you slacken the bolt off that attaches the skeg anode try rotating it a few degrees to starboard from the centreline, this should make a difference, if this improves it then trim it to stbd until you're happy with the balance. When everything is i balance the RIB should also track pretty straight once on the plane.

The up/down trim shouldn't impact port/stbd trim but I could be wrong.

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Old 21 June 2021, 19:33   #7
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Boating Performance

Quite a good article including the impact of trim on torque induced steering.
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Old 21 June 2021, 21:37   #8
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Is your engine mounted dead centre? Is your boat weight biased port or starboard, I would always mount most of weight starboard to counteract prop torque. Battery, helm, oil etc.

As others have said over trim in can cause the port lean or an engine too low on the transom
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Old 22 June 2021, 08:18   #9
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Could there also be some water in the hull and torque reaction then shifts it to the port side where it stays there until you come to rest?
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Old 22 June 2021, 08:40   #10
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Take a look at this:
www.rib.net/forum/f45/willard 7m seaforce repower


Changing the prop reduced the dangerous torque roll. The effect must be influenced by the shape of the propeller thrust.
See also:
Propeller Basics Pt3
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Old 22 June 2021, 09:42   #11
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Thanks Voodo.
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Old 22 June 2021, 09:45   #12
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Quote:
Originally Posted by Pipster100 View Post
If your RIB is sitting flat at rest and it's not a weight issue causing the port trim, I'd look at the skeg anode, usually there is a fin that you can trim to counteract the rotational force from the prop. As your prop rotates clockwise (going forwards) as well as providing forward thrust it also induces a rotational force. Excuse my very quickly drawn sketch but you'll see the point I'm trying to make. If you slacken the bolt off that attaches the skeg anode try rotating it a few degrees to starboard from the centreline, this should make a difference, if this improves it then trim it to stbd until you're happy with the balance. When everything is i balance the RIB should also track pretty straight once on the plane.

The up/down trim shouldn't impact port/stbd trim but I could be wrong.

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Thanks Pipster. Your diagram and explanation are really helpful. Will try adjusting when I am down at the weekend.
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Old 22 June 2021, 09:46   #13
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Ribeye you say, which way is the lean?https://www.facebook.com/groups/6868...9068999610791/
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Old 22 June 2021, 09:47   #14
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Quote:
Originally Posted by gtflash View Post
Is your engine mounted dead centre? Is your boat weight biased port or starboard, I would always mount most of weight starboard to counteract prop torque. Battery, helm, oil etc.

As others have said over trim in can cause the port lean or an engine too low on the transom
Thanks GTflash. I believe it is mounted dead centre along with batteries, helm etc.Useful to know about placing more weight on starboard too.
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Old 22 June 2021, 10:52   #15
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Quote:
Originally Posted by mhill View Post
Ribeye you say, which way is the lean?https://www.facebook.com/groups/6868...9068999610791/
Hi mhill. Thanks for the link...lmao here. The lean is to the left as in the picture on FB!! Not sure we have experienced it that bad yet...shows the importance of always wearing a kill chord!
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Old 22 June 2021, 10:53   #16
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Quote:
Originally Posted by vitalspark View Post
Could there also be some water in the hull and torque reaction then shifts it to the port side where it stays there until you come to rest?
Thanks vitalspark. Have not noticed water in the hull yet and will look out for this. Cheers.
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Old 22 June 2021, 10:56   #17
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Quote:
Originally Posted by Limecc View Post
Take a look at this:
www.rib.net/forum/f45/willard 7m seaforce repower


Changing the prop reduced the dangerous torque roll. The effect must be influenced by the shape of the propeller thrust.
See also:
Propeller Basics Pt3
Thanks Limecc. I have a spare prop so my try that out to see if there is a difference. The link is really useful-much appreciated.
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Old 22 June 2021, 10:59   #18
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Quote:
Originally Posted by GuyC View Post
Boating Performance

Quite a good article including the impact of trim on torque induced steering.
Thanks for sending this useful link GuyC. Lots to learn....
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Old 22 June 2021, 12:46   #19
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Quote:
Originally Posted by Depdawg View Post
Thanks Limecc. I have a spare prop so my try that out to see if there is a difference. The link is really useful-much appreciated.
You want one with a high rake and one that's not sold as giving stern lift, this should produce a narrower cone.

Also GTflash mentioned it already, make sure the engine is set optimally as high as possible while giving no prop ventilation.
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Old 22 June 2021, 16:11   #20
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Thanks everybody

Have spoken to Ribeye today and they have that the solution is to trim it to half way (on the electronic pitch gauge) and this should solve it. Will update once I have done this.

Thank you for everybody’s helpful comments and advice. Much appreciated.
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