I have owned my Morgan OI 51 for 12 years and maneuvering at slow speed is difficult.
In cruising trim she is just south of 25 tons. It takes few bursts of big power to turn her quickly - in tight situations. The Diesel
is a Perkins
6.3544 NA. Most of the 51's I have seen are 4 cylinder...
The videos on line for trawlers jockeying - are quite amazing -with articulating flap rudders. The "flap" can double the angle of the rudder. Mine is 35 degrees per - side - so I might see 70 degrees deflection of the prop wash.
I like this style of linkage it is up high and it could be made with a cover plate to keep sea weed from getting caught and removed for maintenance www.nauticexpo.com/prod/talleres-blanchadell-sl/product-34204-514442.html
If you page down there is a video
Here is another link to one with a lower gudgeon that I have on the 51
Here is one with a closed Linkage that would work
better on sailboats with a faired in cover
Here's one in Composite (or Fiberglass) that I could blend into my existing Rudder if I cut off say 25% off the back-
I am a welder and really good with fiberglass
- so the work doesn't bother me. I am also a commercial
diver so maintenance
underwater is not an issue either...