Rudder Tie Bar

[Boathook]

I want to alter the position of the tie bar on the rudders of my cat. The drawing isn't to scale but the leverage point will be less than existing. The quadrant for the steering wires will still be at the same location. Will the steering become heavier with reduced 'leverage' on to the second (starboard) rudder. I suspect that many years ago I could have worked it out, but now ......
If I do move the tie bar it will make access easier to 2 lockers.

 

[TLouth7]

The steering force should be the same. The force in the bar (and therefore in its attachments) will be greater by a factor of ~2 as drawn.

 

[pyrojames]

Tie bar loads and Pintle loads will be proportionally higher.

 

[TLouth7]

On further thought, the pintle force on the slave rudder will be reduced as the tie-bar will be counteracting some of the rudder sideload. Correspondingly the pintle force on the driving rudder will be increased (by a considerable margin).

 

[Boathook]

Thanks for replies. I hoping to get down there tomorrow and refit the old tie bar and sort out whats required for the new one.

 

[C08]

Hi
I am interested in this concept as my (8m) cat has the large holes for the rudder connecting bar which worry me when in rough weather with respect to taking on water although I have the corner with the cables entry to the interior sealed up to above the slots. The outboard rudder bar will avoid taking on water there and enable those large 3"x6" slots to be sealed up.
How are you considerering linking the rudder bar to the rudders when outboard of the standard setup.

 

[pyrojames]

I have just read the keel loss thread on the racing forum. If you are going to modify the tie bar, please make sure you understand all the loads on the upper and lower pointless on both rudders and how those will change if you change the tie bar.

 

[Boathook]

Hi
I am interested in this concept as my (8m) cat has the large holes for the rudder connecting bar which worry me when in rough weather with respect to taking on water although I have the corner with the cables entry to the interior sealed up to above the slots. The outboard rudder bar will avoid taking on water there and enable those large 3"x6" slots to be sealed up.
How are you considerering linking the rudder bar to the rudders when outboard of the standard setup.

Not to sure on how to connect at present and it does mean that I will have to modify the engine steering as well. I need to get down and do some more measuring, etc but things are all over the place with this virus.
If your tie bar is a standard set up into the rear lockers, all 8m's are the same with no problem as far as I'm aware, as the locker is self draining.

 

[Boathook]

I have just read the keel loss thread on the racing forum. If you are going to modify the tie bar, please make sure you understand all the loads on the upper and lower pointless on both rudders and how those will change if you change the tie bar.

Thanks for your concern pyrojames but the rudder mounts are over engineered on my 1970's built cruising cat. I am more worried about whether the loads on the steering will be heavier, as it can be very heavy with present set up which is standard for my boat.