Model - Twin Rudders Version 2

Here's my second attempt at the twin rudder system. It's more compact and everything will fit within a decked narrow  intermediate section between the end of cockpit bulkhead and another bulkhead in front of the outboard well area.  Stern area is now very clean with just the push rods attached to the rudders and these have little lateral movement so will be scope for a couple of narrow hatches on the sides and plenty of buoyancy to be built in. I tried my hand at a video to demo the twin rudder system.

Model - Steering Systems and Twin Rudders

I'm now getting into uncharted waters - design variations not drawn by Iain Oughtred or Kees Prins - I will be getting back to them on this before the build. I wanted twin rudders so I can centrally locate the outboard and so steering on the wind and in rough water will give more efficient rudder control.  I also want to see if I can rig a removable stick rudder control in the cockpit as an option to a tiller (I will still have a tiller but linked to the same system controls).    Here's a few pics of a construction model I have set up specifically to test this out (and also test the cockpit people space).  Note my shop made mannequins of 1/5th size me and crew (note: crew has not committed to joining this ship yet).

Below is pic of transom with outboard cutout and sticks representing rudders (at 12 degree incline to vertical) and end of cockpit bulkhead. The rods at the top lead into the edge of the cockpit seat where the stick control attaches. The lever system here uses hobby shop ball joints - real boat would have stainless steel rodends and rod and system would be more compact than here. Rods will not project through the transom as shown here.

 

Here's the skipper and crew seated in the cockpit and the stick control in the skipper's left hand attached to the rod which feeds through the edge of the cockpit seat to behind the bulkhead. There's a fairly small arc of movement of the stick control (+/- 30 degrees) which transfers to +/- 45% at the stern where it meets the rudder cranks.  Leverage is provided by length of stick and rudder crank for about 4 to 1 ratio of effort. Above you will see a bar that ties the the two rudder controls together, low down just behind the bulkhead.

 

I'm not convinced this lever system is viable. Whilst it all works fine in model, the lever angles are not optimum and the system is cluttering up stern space for buoyancy and storage.  I am now starting work on a drum and rope system which will be more compact - but still including cockpit joystick and optional tiller (each removable). It will work off rudder cranks higher up on the transom and with less crank cutout in the transom. The outboard cutout will be reduced because I am now convinced I need long shaft rather than short shaft.  Current motor thinking is Tohatsu 4 stroke 6HP with external tank.

I'm happy with the cockpit space and the extra 5 inches I have added here by extending the stern.  The space between cockpit and transom will be taken up a short decked area with mainsheet traveler and removable gallows space and them followed by drainage well under the motor cutout and space for 12 litre fuel tank, fenders and wet weather gear storage - lots of buoyancy will be built it below this and along hull around this.