TON Class

TON Class Technical Data

Dimensions:  Length 152 ft x Beam 28 Ft X Draft 8 ft 
Gross Displacement: 360 tons
Carrying capacity: 65 tons 
Propulsion: Original ships: 2 x Mirrlees 12–cylinder Diesel engines =  2500 HP 
Later ships and retro-fitted: 2 x Deltic diesels, 12 banks of 3 pistons = 3,000 HP 
Max Speed: 15 knots. 8 knots towing with all sweeps streamed  
Range: 2300 nautical miles at 13 knots on one engine for fuel economy 
Navigation Radar: Decca Type 1006 – 35 miles range 
Mine hunting Sonar: Plessey Type 193. Echo sounder to 300 feet depth. 

Gun Armament: 

Sweepers and Hunters: 40 mm Bofors 40/60 on fo’cstle 
Sweepers: Twin 20mm Oerlikon cannon abaft funnel, 2 x 7.63 GP Machine Guns for bridge wings  
Rifles, submachine guns and pistols for boarding and landing parties 

Complement:

Senior Officer of Squadron: Commander 
Commanding Officer: Lieutenant Commander or Senior Lieutenant 
First Lieutenant (later XO): Lieutenant 
Watchkeepers (Gunnery and Navigation Officers): Sub Lieutenants , One or two Midshipmen under training. 
Senior Engineer: Chief Petty Officer Artificer, assisted by 2 POMEs 
Chief Bosun’s Mate: Leading Seaman 

12 ft slow motor boat. Replaced in Fishery Protection vessels and Minhunters by Gemini RHIB 

Mine Sweeping Equipment: 

Oropesa Wire sweeps, MM11 Magnetic sweep, Acoustic Hammer, Acoustic Displacer  
N.B. Acoustic Oscillator and Acoustic Explosive Sweeps Discontinued in early 1960’s 
Mine hunters replaced magnetic and acoustic sweeps with Single Patient Divers Recompression Chamber and magazine for Mine Disposal Weapon re-loads