Half Model

[Bob WilsonParticipant @bobwilson59101]

This is a half model of the steel-hulled wool clipper Peleus, A & J H Carmichael, Greenock. I made it just as a demonstration of the lines and shape of a large steel sailing vessel of the late 19th century. The "gunports" were just decoration, painted on. They did not open, and they did not conceal guns!

[Bob WilsonParticipant @bobwilson59101]

[Bob Abell 2Participant @bobabell2]

Very precise model Bob

But I'm curious about the very small rudder, it must have been very unresponsive?

Bob

[Bob WilsonParticipant @bobwilson59101]

It wasn't very small, it was typical of a sailing ship rudder, and most of them were very responsive. The model was built using the original lines plan of the ship. Here is another plan of a different ship. They were all very similar.

[Colin BishopModerator @colinbishop34627]

Sailing ship rudders didn't need to be large. They worked by introducing a hydrodynamic imbalance between each side of the hull and the ship then virtually steered itself round. A sort of aerofoil effect really.

Colin

[Bob WilsonParticipant @bobwilson59101]

Moving the rudder off centre caused drag, that a sailing ship didn't really need. A good helmsman could keep the ship on course in good weather with the rudder midships most of the time, but just deviating slightly to get it back occasionally. As Colin says, design had evolved to a pretty good system in the latter day sailing ships.

Bob

[Malcolm FraryParticipant @malcolmfrary95515]

Much sailboat steering is done by trimming the sails to give different forces fore and aft to start the hull rotating either into, or away from, the wind. The rudder was more a trim tab to either help or compensate for this.

Looking at early (pre radio) model yacht designs the rudders are quite modest, because they are there to maintain a course. With the addition of radio control, rudders with much more authority are needed because they are there to steer.

I imagine that changing couse on a square rigger involved a lot more than just having the helmsman point it in a different direction as in the movies, but would involve a lot of the crew retrimming the sails.

[Colin BishopModerator @colinbishop34627]

Malcolm, as you say, the rudder would act more as a trim tab. Unless involved in close quarters tacking the sails would be trimmed to the desired course and, as Bob W says, the rudder would be used to correct minor changes such as yawing as wind strength varied. In the old square rigger times the same course might be steered for days on end if the (trade) winds were favourable.

Models will behave differently due to the scaling down effect of the vessel whilst the water remains the same and the wind strength scales up!

Colin

[Bob WilsonParticipant @bobwilson59101]

We swung the yards to each breath of air, 'midst the heat and the tropical rain,

Then the wind would fly to the other beam, and we'd swing them round again!

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