LittleSister
Well-known member
Obviously the RAM arm is completely different.It just goes to a quadrant under the deck. Stays attached and you just press auto and standby on the controller in the normal way.
If a wheel pilot is out of your price range then do not even think of a below decks type as even before you think about fitting it the hardware alone is twice the price. The fundamental difference is that the below decks drives , whether they be ram or rotary have a clutch to engage/disengage. Even the wheel pilot does not have this, being engaged by a friction mechanism on the belt.
. . . Raymarine's "solution" for larger tiller steered boats is to use the more sophisticated electronics of the below decks type but with a more powerful ram than the normal tillerpilot, but seem to have accepted it is not possible to design a reliable clutch operated one for external use. There is a French make that does offer this and used on the hot shoe racers, but the cost is eyewatering compared with the Raymarine and B&G gear
Thanks, now I understand. It was the 'clutch' arrangement I was trying to understand.
I was naively assuming the under deck ones were just ordinary tiller pilots connected through some separate connect/disconnect arrangement, and it was the latter I was trying to understand. I now see the under-deck types are a completely different device kettle of fish (and price bracket!) to the tillerpilots, with some sort of built in clutch.
The biggest practical constraint to fitting a below decks type drive is access to the rudder stock to fit the arm or a quadrant as traditionally the stock is in a tube full of seawater with no exposed stock. modern performance boats like flaming refers to are specifically designed with the stock going into a sealed tube just like a wheel steered boat with enough stock exposed to fit the steering arm. Some with twin rudders have exposed linkage to the 2 stocks and the drive operates on the linkage. On some boats like the one illustrated mount the drive in a locker, often using a "Python" or cable drive through flexible bellows to an arm on the existing tiller.
The LM27 (and other LM motor sailers) have a partially exposed shaft with two quadrants under the aft deck, one connected to the rudder (and removable tiller), and one connected to the wheel, and the two quadrants can simply be latched together or unlatched.
I was fantasising about a third quadrant, driven by a tillerpilot, which could separately (concentrically) be latched to the rudder quadrant, though the length of the lever arm required/ram arm gearing is a major stumbling block. (Someone who was a whizz at machining gears (which I'm not) could either change the ram arm gearing, or have the tillerpilot motor driving the quadrant directly and dispense with the ram arm altogether.
.