What happens at sea trials of submarines? There are more to test and it is done by stages.
Source is:
https://fas.org/nuke/guide/usa/doctrine/navy/jfmm/vol1/CH_04.htm
The important and common parts are highlighted.
4.4.3 Alpha Sea Trial (Submarines only). A submarine's first underway period primarily conducted for propulsion plant testing and the initial tightness dive. (First ship of each class normally conducts a dive to Test Depth during this trial.)
a. Testing. The tests and evolutions to be carried out while on the surface en route to the test dive area, just prior to the initial dive and during the initial dive are identified in Appendix D of this chapter.
b. Restrictions. The following rules apply to the conduct of trials and tests associated with ship construction, Ship Program Manager sponsored Trials/Tests or any other situation where the ship is requested to conduct trials or tests:
(1) No test or trial event shall be conducted that requires crew intervention to avoid exceeding normal operating limits. Trial agendas will be based on the expectation that the ship will remain within normal operating limits of the Submerged Operating Envelope (SOE) and at angles less than 30 degrees.
(2) The trial director must be prepared to project whether the next event might exceed normal operating limits based on the empirical results of the previous event. A run that is predicted to exceed normal operating limits should be deleted along with the more demanding runs of that sequence.
(3) Any run which will result in exceeding normal limits of the SOE or 30 degree angles but which is essential to provide adequate test data must be specifically approved by the TYCOM. The test/trial sponsor will obtain this permission.
(4) A violation of the SOE limit or exceeding a 30 degree angle, not previously approved, shall be reported by unit Situation Report (SITREP). No further testing or trials shall be conducted until TYCOM concurrence is obtained.
(5) Specific written approval by the TYCOM is not required to operate outside the upper limits of the SOE, i.e., shallow and fast, while conducting the following operations during Sea Trials or tests in accordance with an agenda approved by the ISIC, Ship Program Manager or higher authority:
(a) Conducting full power runs or cavitation curves.
(b) Ship Program Manager sponsored acoustic trials in accordance with an approved acoustic trial agenda.
(6) The first underway tests will be limited in scope. The initial tightness dive will be a deliberate, planned, step-by-step evolution as defined in Appendix D of this chapter, using conservative angles and moderate speed. The maximum water depth for this dive shall be 400 feet, as prescribed by reference (k).
c. Escort.
(1) The submarine shall be accompanied by an escort properly equipped with sonar communication equipment. The escort ship must have the capabilities identified in Appendix E of this chapter. Specifically an escort is required for:
NOTE: FOR ALPHA SEA TRIAL, A BACK-UP ESCORT WILL BE ASSIGNED AND READY IN CASE OF FAILURE OF THE PRIMARY ESCORT.
(a) Initial tightness dive after construction and the first dive to any deeper depth.
(b) Initial deep dive after construction.
(c) Emergency Main Ballast Tank (EMBT) blow test under the following conditions:
- Blow for first time from each depth. Trial agenda will specify depths.
- Any blow from greater than 400 feet. Rationale is to give submarine added protection to prevent interference from any surface contact.
NOTE: IN ALL CASES, HULL STRENGTH/TIGHTNESS AND VALVE OPERATIONS WILL HAVE BEEN TESTED TO A DEPTH EQUAL TO OR GREATER THAN EMBT BLOW DEPTH BEFORE TESTING EMBT BLOW SYSTEM.
(d) The second and subsequent underway periods if major hull and system work has been accomplished since the last Sea Trial.
(2) Alternate Escort. If a surface ship meeting the requirements of Appendix E of this chapter is not available, then a submarine with the required capabilities will be assigned. In any event, each situation must be examined on a case basis and approval by the TYCOM must be obtained to conduct the initial tightness or test depth dives.
(3) When an escort ship is other than a submarine, an officer qualified in submarines (Gold Dolphins) must be embarked during the escort duty.
(4) Assignment of Deep Submergence Rescue System (DSRS). A DSRS consisting of a designated Deep Submergence Rescue Vehicle (DSRV) and a DSRV support ship, will be placed in a modified alert status at the beginning of those Sea Trials requiring an escort for:
(a) Ship's initial trim and deep dive events.
(b) Subsequent Sea Trials until the completion of the initial dive to design test depth.
(c) If, in the TYCOM's judgement, a Sea Trial requires an escort due to major hull cuts, etc., the TYCOM shall obtain Ship Program Manager concurrence when determining the need for escort/DSRS services. The ship conducting Sea Trials will notify Commander, Submarine Development Group One, San Diego, CA when DSRS services are no longer required due to completion of the events necessitating the alert status or due to delays in completing Sea Trials.
d. Reporting Criteria. The Supervising Authority is responsible for reporting the satisfactory completion of Alpha Sea Trial to the Ship Program Manager. Volume I, Chapter 2, Appendix C refers.
4.4.4 Bravo Sea Trial (Submarines only). Bravo Sea Trial is generally the submarine's second underway period and first dive to Test Depth.
NOTE: THE FIRST SHIP OF EACH CLASS NORMALLY CONDUCTS ITS FIRST DIVE TO TEST DEPTH DURING ALPHA TRIAL.
a. Testing. The tests and evolutions to be carried out following the initial tightness dive and prior to the deep dive, during the deep dive, submerged following the deep dive, and on the surface following the deep dive, are identified with Appendix F of this chapter.
b. Restrictions. As specified in paragraph 4.4.3.b of this chapter.
c. Escort. As specified in paragraph 4.4.3.c of this chapter.
d. Reporting Criteria. With the exception of reporting the deficiencies during the trial, reporting of the completion of Bravo Trial is not required. Daily SITREPs to the Supervising Authority and the Supervising Authority's message concerning the completion of all trials (Volume I, Chapter 2, Appendix D refers) satisfies the reporting requirements.
4.4.5 Charlie Sea Trial (Submarines only). Charlie Sea Trials are conducted prior to CT. Bravo Trial retest items are also included in this trial. The standard restrictions and escort requirements as specified per paragraphs 4.4.3.b and 4.4.3.c of this chapter apply.
4.4.6 Acoustic Trials (Platform and Radiated) (Submarines only). New construction acoustic trials, performed by the shipbuilder, are accomplished to determine,
under various conditions of operation, the radiated and platform acoustic signatures of the submarine, the controlling noise offenders including those which are speed dependent, and whether or not the submarine meets its underway noise objectives. Proper operation of systems/components and the use of proper personnel quieting techniques is vital for successful acoustic measurements. Acoustic trials performed by Naval Surface Warfare Center (NSWC) are used to establish the ship's baseline signature for normal operating conditions
by performing independent measurements under preset conditions of speed, depth, aspect angle, and machinery line up. It is imperative that Ship's Force understand that this trial will determine its future operating conditions during various "patrol quiet" conditions.
4.4.7 Shock Trials.
Shock Trials are designed to test the survivability characteristics of a ship under deliberate and controlled conditions. Normally scheduled for the first ship of a class just before Post Shakedown Availability (PSA); Shock Trials satisfy Congressionally mandated Live Fire Test and Evaluation requirements. Ship Program Managers are responsible for the development of a management plan for the conduct of Shock Trials.
4.4.8 Acceptance Trials/Combined Trials/Final Contract Trials/Guarantee Material Inspection.
a. Reference (d) tasks the Board of Inspection and Survey (INSURV) with conducting an independent verification of the readiness of a newly constructed ship prior to its acceptance into Naval Service. Reference (l) states that the procedures for conducting trials and inspections shall be specified by the President, INSURV. References (f) and (h) provide those procedures for submarines and surface ships respectively. References (f) and (h) are augmented by reference (a) in their application to nuclear powered ships. References (m) and
provide detailed information concerning the documentation of deficiencies. In addition, each Supervising Authority, TYCOM, the Naval Ships' Technical Manual (NSTM) and reference (o) all provide additional information concerning AT/CT/GMI/Final Contract Trials (FCT). TYCOM directives are identified in the applicable TYCOM 5215 Notice.
b. Prior to the acceptance and delivery of a new ship, all machinery, electronics and weapons systems installed shall be subjected to ATs to determine that the installations are capable of meeting performance specifications. Depending upon the platform type these trials are referred to as either ATs, or CTs. This independent verification of the ship's readiness for acceptance and recommendation for fleet introduction, as specified in reference (d), is the responsibility of the President, INSURV.
c. These trials are generally two part evolutions. There is an underway portion during which time the INSURV observes the performance of the ship and all equipment and systems. Upon completion of the underway portion, trial board designated equipment and associated components are disassembled for post trial examination (the open and inspect evolution). References (f) and (h) provide amplifying information concerning this issue.
d. CTs, usually the norm for submarines, is a combination of ATs and FCTs. The AT for non-submarine platforms results in a conditional acceptance primarily based on the fact that the ship still requires fitting out. Submarines go through the fitting out period during the construction phase which produces a completed ready for sea vessel at delivery. The standard restrictions and escort requirements as specified per paragraphs 4.4.3.b and 4.4.3.c of this chapter apply.
e. FCTs are conducted after the ship has been fully equipped, armed, made complete and ready for service. These trials are normally held just prior to PSA and prior to the end of the guarantee period. Their objective is to determine if there are any defects, failures or deterioration, other than that due to normal wear and tear, directly related to shipbuilder fault which have not been corrected or resolved. The scope of FCTs is essentially the same as AT.
f. A GMI is a material inspection, conducted on submarines prior to PSA by an INSURV in accordance with reference (f).
g. INSURV reports from previous ships as held by the Supervising Authority provide familiarity with problems and corrective actions already taken. In addition, these reports provide a baseline for conducting shipboard inspections and generating inputs for the PCO's monthly progress reports.
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