MacGregorSailors.com

Whilst only been sailing for a month or so, I have been driving warships from patrol boats to frigates to battle tankers for 7 years, I also coxswain'd prop and jet rhibs. From my training and experience (a lot of it was the captain saying I was doing it wrong) I can attest that no more than 30 degrees of rudder should be used for the most efficient turn. Any more and you start braking, loose way and increase the turn time.

There is also a big difference in turn acceleration in how quickly you apply your wheel. Digging in straight to 30 will bury your bow and swing you around a lot faster than a gradual increase, but more counterwheel is needed.

One of the best tools we have on the bridge is the rudder angle indicator, wouldn't be without it, and hope to install one when I finally get my pointy caravan, probably as part of an autopilot

The Mac rudders angle so extremely because the sail rudders and the motor are attached to the same linkage. While 30 degrees is maximum for sail, you need more than that when powering without the daggerboard. You just have to turn slowly and let the boat tell you what's going on.

Thats because the outboard isnt a rudder, its vectored thrust, jetboats are the same way with the bucket. itsead of deflecting the flow of water over a rudder, creating a force that turns the boat, the outboard prop is used like a bow thruster, pushing the boat off centre. the pivot point of the boat would be completley different when under sail, which would be in a conventional midships to forward position, to much further aft when powering, particularly at slow speeds. at slow speeds, the sail rudders would do very little, as there is no flow over them.

having the daggerboard down whilst powering, at slow speeds particularly, would bring that pivot point forward. but you would only be doing that if you were coming in to berth at a deep jetty, instead of the boat ramp. it would also counter drift aswell.

high speed powering should still follow the 30 rule, as the flow of water over the prop stem would act as a conventional rudder, but the shape isnt optimised for it. Of course, when you doing high speed power turns at full lock, you not caring about turn efficiency, your more concerned with making sure your passengers get extremely wet