Rudders, Tillers and Self-Steering Gear – Part Two

7th February 2023

Trim Tab Self-Steering

This is the beautifully built Vertue “Tui of Opua” with its trim tab self steering gear

Last week I had intended to just post a short piece about the repair I have just made to my rudder hangings. Then I got a bit carried away and went on (and on) about rudders in general. That spurred Bruce Morley to drop me a line about his rudder which incorporates trim tab self-steering. Bruce built Tui of Opua himself and launched her in 1994. Bruce and his wife Thelma have lived onboard ever since. The yacht is described by as “one of the finest Vertues in the world” – quite an accolade!

Their trim tab self steering was based on information from “The Blue Book” by Peter Woolass.

When I was researching self-steering before my Atlantic Crossing I did contemplate using a trim-tab system on Sumara but I never plucked up the courage to slice through my rudder. I ended up going for a Windpilot system, but more of that later (Part Three!)

The big advantage of the trim-tab system is that it avoids needing a mass of stainless tubes to support the weight of the servo pendulum type of self-steering. The tab is really a servo-tab enabling the relatively light force of the wind against the vane to deflect the trailing edge of the rudder and steer the boat.

Below are some drawings and photos which show off the mechanism which Bruce successfully built for their yacht.

Side elevation of the trim tab self-steering from
Peter Woolass’ blue book “Vertue”
And here is the side elevation in real life on Tui of Opua
From “The Blue Book” “Vertue” by Peter Woolass
Beautifully executed mechanism on Tui of Opua
It looks tough and purposeful
That’s not going anywhere – if you know what I mean!

Thank you Bruce for sending through those photos. I am sure they will inspire some Vertue owners to utilise the same system.

Next up will be servo pendulum self-steering gear.

One response to “Rudders, Tillers and Self-Steering Gear – Part Two”

  1. […] the most elegant solution for Sumara would have been the trim-tab as detailed by Peter Woolass and used by Tui of Opua, but I really didn’t what to take a saw to my rudder and probably didn’t feel confident […]

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