Torpedo Deflection Sight Mark I
A Torpedo Deflection Sight Mark I was the designation given to British torpedo directors designed for above-water tubes when they were adapted into torpedo deflection sights. The line of sight directors, however, were designated T.D.S. Mark II after alteration.
By the end of August, 1918, had been or was being fitted to tubes in all light cruisers "Attentive" and after and TBDs "E" class and after armed with RGF and RNTF heaters. Due to limited numbers of Mark I, some later ships are getting T.D.S. Mark III.
Designed before introduction of medium speed setting (ARTS 1916, p 45), and so the deflection rings are for the 3 speeds of one Mark of torpedo. When getting medium-speed-capable torps, these would require adaptation.
|Large Deflection Rings for T.D.S. Mark I |
The distinguishing letters would be circled. Subscripts denote the reverse side of another ring.
|Distinguishing Letter||Graduated Speeds (knots)||for Torpedo Marks|
|S||25, 29, 35||21-in Marks IV* and V with 35-knot setting|
|S1||25, 29, 44.5|
|L||21, 25, 35||21-in Mark IV with 35-knot setting|
|L1||21, 25, 44.5|
|K||21, 25, 44.5||21-in Mark IV|
|K1||19, 24, 44.5||21-in Mark II*****|
|Q||19, 24, 35||21-in Mark II***** with 35 knot setting|
|Q1||18, 23, 35||21-in Mark II-II**** E.R. 3 with 35-knot setting|
|M||19, 24, 44.5||21-in Mark II*****|
|M1||18, 22, 44.5||21-in Mark II-II**** E.R. 3|
|P||18, 23, 44.5||21-in Mark II-II**** E.R. 3|
|R||18, 23, 44.5||21-in Mark II-II**** E.R. 3|
|R1||18, 29, 45||21-in Mark I-I*|
|T||19, 29, 41||18-in Mark VII-VII*****|
|T1||19, 29, 35|
By mid 1919, delivery of all the rings was still being completed.
- Annual Report of the Torpedo School, 1916, pp. 25-26.
- Annual Report of the Torpedo School, 1917, p. 190.
- Annual Report of the Torpedo School, 1918, p. 155.
- Discrepancy between Mark I and Mark II