Table:
text: Siegfried von Forstner
Ships attacked
Ships attacked
Date_ Ship Nationality Tonnage Fate
7 February 1942 Kalliopi Greece 4695 Sunk
7 February 1942 Robert E. Hopkins Great Britain 6625 Sunk
7 February 1942 Toward Great Britain 1571 Sunk
8 February 1942 Newton Ash Great Britain 1571 Sunk
11 May 1943 Antigone Great Britain 4545 Sunk
11 May 1943 Grado Norway 3082 Sunk

text: Siegfried von Forstner
Ships attacked
Ships attacked
Date_ Ship Nationality Tonnage Fate
16 May 1941 Llangibby Castle Great Britain 11951 Damaged
13 April 1942 Empire Progress Great Britain 5249 Sunk
30 April 1942 Ashkhabad Soviet Union 5284 Sunk
2 May 1942 USS Cythera USA 602 Sunk
2 November 1942 Dalcroy Great Britain 4558 Sunk
2 November 1942 Empire Antelope Great Britain 4945 Sunk
2 November 1942 Empire Leopard Great Britain 5676 Sunk
2 November 1942 Empire Sunrise Great Britain 7459 Damaged
2 November 1942 Rinos Greece 4649 Sunk
7 February 1942 Afrika Great Britain 8597 Sunk
7 February 1942 Daghild Norway 9272 Damaged
7 February 1942 Henry R. Mallory USA 6063 Sunk

Question: What is the highest tonnage for a British ship named Newton Ash under Siegfried von Forstner?