rudders

[michael kemishParticipant @michaelkemish72883]

On a twin screw boat, is it better to offset the rudders inboard or out board of the prop shafts?

I ask,  because I will have to re-grease the propshafts on a regular basis, and there will not be a lot of finger room to regularly pull the rudders out.

And on the same idea, what is the best way to set up the prop shaftprop tubes, bearing-wise? I have been told 3 different systems so far!

Mick

 

[michael kemishParticipant @michaelkemish72883]

[Andy BaileyParticipant @andybailey80218]

Could you fit greaser tubes on the propshaft tubes inside the boat , not sure what you mean about the other question though , what model are you building ? this may help .

regards Andy

[michael kemishParticipant @michaelkemish72883]

Hi Andy,

If I place the rudders directly in line with the propshafts, the only way to remove the shafts would be to remove the rudders. There will not be a lot of finger room to get to the top of the rudder shafts.

I can offset the rudder shafts either inboard or outboard of the line of the propshafts, preferably inboard (finger room!). It’s not ideal, but with twin engines and tank steering, low speed turning should’nt be affected, and at higher speeds, at least one of the rudders will be in the prop wash.

Is there any reason why inboard is better than outboard, or vice versa?

Mick

 

[Paul TParticipant @pault84577]

Hello Mick

 

There are differing reasons involving fluid flow, cavitation and push rate that affect the location of rudders on real ships but on models these reasons dont really matter as buildability and maintance become more of a problem.

 

If fitting the rudders inboard works for you then that is the best place to fit them, if you are still worried about the ability of the rudders to turn your model then increase the surface area of the rudders (fwd to aft length) to pick up more of the prop thrust.

 

Paul

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