It also carried a single fin and a deep rudder, which moved in a cut-out between the elevators.

The wide chord, deep rudder reached to the bottom of the fuselage between divided elevators.

The parallel chord horizontal tail had separate elevators with the deep rudder moving between them.

"It provides me with a very deep rudder, a stabilizing influence in my life," Mr. Thurman said.

Both elevators and the generous, deep rudder were horn balanced; the rudder also carried a trim tab.

The new fin had the shape of an equilateral right angled triangle, and the now deeper rudder was slightly reduced in chord.

The tail surfaces were also revised, with a single-piece elevator with a straighter leading edge and a taller, deeper rudder.

At the rear the tailplane was mounted at mid-fuselage under a long chord fin with a strongly swept leading edge, carrying a deep rudder.

This deep rudder, tabbed and horn balanced was likewise square edged, mounted on a very wide chord, shallow, straight edged fin.

At the rear, the tailplane was mounted at mid-fuselage and the fin and deep rudder were straight tapered except near the keel and almost triangular above the fuselage.

Lufthansa used it in trials and a number of changes were made to the final prototype (V3), including a wider chord, less deep rudder and a faired tailwheel plus minor door modifications.

The square tipped fin has a swept leading edge and a curved fillet; it carries a deep rudder with a straight trailing edge, which extends between the elevators to the bottom of the fuselage.

Two variants were produced, the SA.6 Sealand I and the SB.7 Sealand III, an extended version with longer wings, a deeper rudder and a strengthened hull.

The empennage is also straight tapered, with a forward set tailplane mounted on top of the fuselage, far enough forward on the fin to require only a small cut-out for movement of the deep rudder.

Together, the fin and rudder were oval; the trapezoidal tailplane with rounded balanced elevators was on the top of the fuselage and the deep rudder required a gap between the elevators for its movement.

At the rear, the T.1 had a conventional tailplane and elevators but there was no fixed fin, only a deep rudder which ran between and well below the elevators to the struts that also carried the tail skid.