These new A Class submarines were basically an enlargement of the T Class, with a construction that was simple, fast and so arranged as to utilize many of the materials set aside for the T boats. The A Class, perhaps the most successful of all 'traditional' types of pre-nuclear submarine, were fitted with an effective air-conditioning system: air warning radar which could function at periscope depth; a high flared bow for excellent sea performance; formidable armament of ten 21-inch torpedo tubes, and had an appreciably reduced underwater noise level.