Propeller axel angels?

[Peter NordsjoeParticipant @peternordsjoe33686]

If the plans don’t show it.

[Peter NordsjoeParticipant @peternordsjoe33686]

Hi,

I am scratch building a 70ft Vosper MTB from 1/24 Lambert plans. Now that the hull is almost done I am starting to think of things like propeller angels and spacing. The plans do not quite show this so I am wondering if there is a kind soul out there who might know some basic rules which I should follow.

 

The original has three props but I have chosen to go with just two.

Thanks in advance. Any input is appreciated.

 

-Peter

[ashley needhamParticipant @ashleyneedham69188]

Peter, I dont think there are any hard and fast rules about this, it all depends on the boat, or more importantly, the model.

 

In something like a MTB, balance and access to the bits and bobs is the sort of thing that matters more.

 

For a start, I would have a session in the bath to determine the best place to put the motors and batteries, assuming you have not already decided ,

 

The shafts need to be at a fairly shallow angle, which normally means motors more forward than back, and obviously the rudders need to be aft of the props, with sufficient clearance to change the props without having to  start dismantling things, and not sticking out the back.

 

I would have thought the prop and rudder positions as shown on the plan would be a guide to where you should be placing the “real” ones, although you may want to increase the rudder size a bit, only having two, and it is always easier to cut down rudder size rather than increase it, and so the props may have to shift slightly further forward than plan.

 

Ashley

[Peter NordsjoeParticipant @peternordsjoe33686]

Thanks Ashley.

 

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