TG stands for Training Group (the group of Recruits that graduate on the same day). TG 01 is the training group that begins training the first week of October when the Navy fiscal year begins, meaning that most of the recruits in TG 01 arrive the last week of September. The smallest TG I've seen had 4 Divisions (11/23/2011) and the largest TG I've seen had 15 divisions (11/30/2012 and 02/01/2013), but the Drill Hall was built to accommodate up to 16 divisions. There could potentially be 52 TG's in a year since there are 52 weeks in a calendar year, but the RTC skips about 4 weeks each year. When a week is skipped, the next TG number is advanced to catch up with the week of the fiscal year either immediately or at some point soon after that so that there are times when consecutive TG's do not have consecutive numbers.
A division is approximately 88 recruits who live and train together. There can be as few as 55 to as many as 100 in a division. The division number is important and will help mail get to your recruit when included in the address and will help you find your new Sailor at PIR. Each division, except the 800's and 900's divisions (unless there are 2 of them in a TG), trains with a Brother Division. Brother Divisions are two consecutive divisions beginning with an odd number (001-002 for example). 800's divisions are the divisions for the special warfare candidates. 900’s divisions are the performance divisions. There are 3 types of 900 divisions. There are the Band/Bluejacket Choir/Drill team, otherwise known as Triple Threat (the musicians, singers, and drill team), the Sticks (those who carry the state flags), and the Ship Staff/Honor Guard (the body snatchers, those who guard various things...). (See 800 and 900 Divisions.) Division numbers begin at 001 each year for TG 01. Division 901 is the first 900 Division and Division 801 is the first 800 division and they continue with consecutive numbers until the next fiscal year.
When a group of new Recruits arrives at the RTC, they go through a simple sort - those with a Musician (MU) rating and those with music or flag/drill experience are assigned to a 900 division if those are needed. Those going into Special Ops are sent to the 800 division when there are enough for a division, otherwise, they are assigned to a regular division. There are usually only 25 or fewer 800 divisions a year, so not every TG will have one, but some TG's will have one or two 800 divisions. (See 800 and 900 Divisions.) The remaining recruits are assigned pretty randomly, mostly as they arrive, to one to four additional divisions. When a large number of recruits arrive on the same day as happens during the summer months, that could change to a larger number of divisions that are started on the day of arrival, but seldom are more than four divisions filled on a particular day. In that case, recruits with similar ratings will end up in the same TG, but not necessarily in the same division. Once one division is full, they start filling another, so divisions often end up with groups of recruits from only a few areas. The Recruits' ratings do not influence which division they will be placed in except for those placed in an 800's or a 900's division.
Females are placed in integrated divisions, containing both males and females, or in an all female division and males are placed in either an integrated or all male division depending on the sort as they arrive. 800 divisions are all male most of the year, but can also be integrated divisions at times when there are enough female candidates for AIRR and/or EOD and/or ND to fill a compartment. (See 800 and 900 Divisions.) Division 317 in 2012 was an all female division, but that was a rare event up to that point.and was to honor the W.A.V.E.S. Beginning in the summer of 2013, each TG was to have one all female division, which would be the sister division to an all male brother division, but the practice was discontinued so that it is now rare for there to be an all female division.
Sometimes a division fills and there are only a few recruits remaining from the arrival group; they are held as the first recruits for the next division; or there is a division that is not quite filled and they must wait until the next group of Recruits arrives to fill the division. When recruits have to wait for more recruits to arrive to fill the division, they will be in what is called a Push Division. Some of the Recruits in those divisions will be at the RTC for 7 1/2 weeks (8 Fridays) rather than the 8 1/2 weeks (9 Fridays) that most of the others in the TG will be there. That is more likely to happen for those arriving on a Monday or Tuesday.
Sometimes there are Recruits who are unlucky enough to be held over and are placed in the TG for the next week rather than in the TG for the week they arrived in and are at the RTC 9 1/2 weeks (10 Fridays). That is more likely to happen for those arriving on Wednesday or Thursday or in the wee hours of Friday morning. That happens more in November and December when a large number of recruits ship early due to the Navy Recruiting Holiday Stand-down. It also happens when there is a week without a PIR or if storms cause recruits to arrive on a different day that the day they were sworn in. It also happens when a large number of recruits are shipped in the summer and early fall because of the need to ship recruits who signed up at the beginning of their Senior year of High School.
Those first 4-11 days after the new recruits arrive are called Processing Days (P-days). P-days can last up to 14 days for some recruits if they have to wait for additional recruits to arrive to fill a division. Although recruits are assigned to a ship and division upon arrival, they do not move to that ship until P-days are over and sometimes things will happen that will change a recruit's assignment or that will cause the division to be housed in a different ship; this is why it is possible that a recruiter might give you an address a day or two after your recruit arrived at the RTC indicating a particular ship and division and then when you get the form letter it is different. For this reason, you are encourage to wait on The Form Letter before sending letters.
The Ship number identifies the building their barracks are in. Each building also has a name of a famous US ship, but few refer to them by the name. It is the division number that is the most important and will help you to find your Sailor on the day of PIR, but the ship number is important when you send them letters because it helps to get the letters to them.
There are 14 different "ships" (barracks), and 12 or 16 divisions in each ship, and every one of them has a different address. Each of the 12 or 16 compartments within the ship can house up to 88 recruits and each ship can house up to 1,300 recruits. Each ship has its own galley, serving 3 nutritious meals a day for up to 1,300 recruits and staff members, as well as multiple classrooms. There are four sleeping compartments on each floor (deck) of the ship. The compartments are designated with a letter A through H (Alpha, Bravo, Charlie, Delta, Echo, Foxtrot, Golf, and Hotel) plus either 01 or 02 after that--A-01, B-02, and F-01 for example. When there are integrated divisions (those with both males and females), the males of the 2 brother divisions share a compartment and the females of the 2 brother divisions bunk together. We seldom see more than 14 divisions within a ship at one time. The older ships appear to only contain 12 compartments. Sometimes a recruiter will give a building number instead of or as well as a Ship number; you do not need to include the building number in the address, but you do need to include the Ship number. Only information in bold below--along with the division number--must be included when writing to your recruit.
Ship 01 (Bldg. 7122): USS Pearl Harbor (LSD-52) xxxx Kansas Street, Great Lakes, IL 60088-3122 (This is the barracks where your recruit will sleep during P-days. Your recruit will not receive mail in this ship.)
Ship 02 (Bldg. 7105): USS Reuben B. James (FFG-57) 3600 Ohio Street, Great Lakes, IL 60088-7105 or 60088-3156
Ship 03 (Bldg. 7104): USS Hopper (DDG-70) 3600 Ohio Street, Great Lakes, IL 60088-3156 or 60088-7103
Ship 04 (Bldg. 7103): USS Arleigh Burke (DDG-51) 3600 Ohio Street, Great Lakes, IL 60088-7103
Ship 05 (Bldg. 7102): USS Theodore Roosevelt (CVN-71) 3610 Illinois Street, Great Lakes, IL 60088-3118
Ship 06 (Bldg. 7101): USS Constitution 3510 Illinois Street, Great Lakes, IL 60088-3119
Ship 07 (Bldg. 7117): USS Chicago (SSN-721) 3405 Sailor Drive, Great Lakes, IL 60088-3401
Ship 09 (Bldg. 7116): USS John F. Kennedy (CV-67) 3415 Sailor Drive, Great Lakes, IL 60088-3415 or 60088-3515
Ship 10 (Bldg. 7115): USS Enterprise (CVN-65) 3425 Sailor Drive, Great Lakes, IL 60088-3425
Ship 11 (Bldg. 7114): USS Kearsarge (LHD-3) 3505 Sailor Drive, Great Lakes, IL 60088-3505
Ship 12 (Bldg. 7113): USS Triton (SS-201 & SSN-586) 3515 Sailor Drive, Great Lakes, IL 60088-3515
Ship 13 (Bldg. 7112): USS Marvin G Shields (FF-1066) 3420 Sailor Drive, Great Lakes, IL 60088-3520
Ship 14 (Bldg. 7111): USS Arizona (BB-39) 3410 Sailor Drive, Great Lakes, IL 60088-3510 or 60088-3410
Ship 17 (Bldg. 7121): USS Mason (DDG-87) 2705 Kansas Street, Great Lakes, IL 60088-3140 (This Ship is seldom used for recruits.)
Ship 1 has separate compartments for males and females and is where your recruit will sleep and spend some time during P-days.
Ship 2 houses the 900 Divisions, which can be integrated (Triple Threat and Sticks/Flags) or all male (Ship Staff/Honor Guard) divisions. It contains all of the music practice rooms and instruments. Ship 2 has 16 compartments. Usually one 900 division per PIR group lives here, but occasionally a TG will have two 900 divisions and at least once there was no 900 division in a TG. Join 900's division sailors. (See 800 and 900 Divisions for more information.)
Ship 3 houses both integrated and all male divisions. Ship 3 has 16 compartments.
Ship 4 houses the 800 Divisions, which can be all male or integrated divisions depending on the ratings represented. It is used by recruits assigned as candidates to Naval Special Warfare operator ratings (SEALs or Special Operators, Navy Divers or ND, Special Boat Operators or SWCC, Aviation Rescue Swimmers or AIRR, and Explosive Ordnance or EOD). (See http://sofrep.com/10103/becoming-a-navy-seal-swcc/ and 800 and 900 Divisions for more information.) Ship 4 is also the RCU-Recruit Convalescent Unit-where sick or injured recruits go to heal and be cycled back into another TG. (Join SHIP 04 DIV 2341 for more information.) The FIT Division is also located here. Recruits who have failed a final fitness test (most often the swim or run) are sent here for intensive training in order to pass the test prior to having Battle Stations-21 (BST). Recruits may also be assigned to FIT within the first few weeks at the RTC; they are typically there for 2 weeks and upon completion will be assigned to a new division with a new PIR date. (Join fit program for more information.) When writing to a recruit in a FIT Division, use the above address for this Ship, but put "FIT Division- Male" or "FIT Division-Female" in place of the Division Number or use Ship 4 Div 2347 (for those who failed the run by less than a minute), or Ship 4 Div 2444 (for those who failed the run by more than a minute), or Ship 4 Div 2381 (for those who failed any part of the swim test). The FAST and PASS programs are also here. (See http://www.navy.mil/submit/display.asp?story_id=54872.) Regular divisions can also be housed on Ship 4 if the need arises and will have the nickname of Rifle Division to distinguish them from the Special Ops Divisions.
Ship 5 is for those recruits in the process of being discharged from Boot Camp. It takes 2-3 weeks to be processed out once a recruit is moved to Ship 5 (SEPS). (Join Ship 5 Moms(Formerly Ship 17) and see FAQ about SEPS and http://www.bootcamp.navy.mil/ship5/index.asp for more information.) When addressing letters, use the above address for this Ship, but put "SEPS Male" or "SEPS Female" in place of the Division Number. The address may also include a compartment number, B-02 for a male for example. It is also for THU-Temporary Holding Unit-where recently graduated Sailors go if they are on hold for "A" school--those Sailors with a contract for Culinary Specialist (CS) often find themselves in the THU for one to four weeks after PIR. Those in the THU are in separate quarters from those being discharged. Few are in THU since the change to Friday and Saturday Departures, but some will be sent here while awaiting clearance or to conduct a special physical or while waiting to class up if there is no housing available at the "A" School or for some other reason. (See http://www.bootcamp.navy.mil/ship5/index.asp.) Federal Health Care Center blood collections are also done on Ship 5 when recruits choose to donate blood while at the RTC. (See http://www.militaryblood.dod.mil/ViewContent.aspx?con_id_pk=230&fr=s and http://www.militaryblood.dod.mil/viewcontent.aspx?con_id_pk=813.) Ship 5 is actually located on the main part of the base and not on the RTC side.
Ship 6 was previously the RCU. It has been used for overflow at times.
Ship 7 houses both integrated and all male divisions. Ship 7 is not currently being used for recruits.
Ship 9 houses both integrated and all male divisions. Ship_9_USS_John_F_Kennedy_The_Story_and_History.pdf Ship 9 is not currently being used for recruits. (No recruits have been housed in Ship 9 since the 10/03/2014 TG.)
Ship 10 houses both integrated and all male divisions. Ship 10 is not currently being used for recruits.
Ship 11 houses both integrated and all male divisions. Ship 11 has 16 compartments. Ship_11_USS_Kearsarge_The_Story_and_History.pdf
Ship 12 houses both integrated and all male divisions. Ship 12 has 16 compartments. Ship_12_USS_Triton_The_Story_and_History.pdf
Ship 13 houses only all male divisions. Ship 13 has 16 compartments. Ship_13_USS_Shields_The_Story_and_History_Part_1_of_2.pdf and Ship_13_USS_Shields_The_Story_and_History_Part_2_of_2.pdf
Ship 14 houses both integrated and all male divisions. Ship 14 has 16 compartments. Ship_14_USS_Arizona_The_Story_and_History.pdf
Ship 17 is used for overflow and also for THU. It is also used as the In-processing barracks for those in the NAVET/OSVET Program.
Any ship that houses integrated divisions could be used to house the all female division in each TG.
Three other ships that are important for your recruit are the USS Marlinespike, the USS Chief, and the USS Trayer. The USS Marlinespike is where recruits learn basic seamanship, line-handling, shipboard watch and teamwork. The USS Chief is used to introduce a recruit to the concepts of shipboard damage control, firefighting, and chemical, biological, and radiological (CBR) defense. The USS Trayer is used for Battle Stations-21 (BST). It is an award-winning destroyer mockup that uses special effects technology from the theme park industry to simulate shipboard emergencies as a capstone test of recruits' skills and teamwork.
Your recruit will spend some time during P-days on the USS Red Rover for medical and dental exams and procedures and receive his/her glasses if those are needed. (See http://www.lovell.fhcc.va.gov/locations/USSRedRover.asp.)
If your recruit becomes sick or injured, s/he may visit the USS Tranquillity. (See http://www.lovell.fhcc.va.gov/locations/USS_Tranquillity.asp.) The USS Tranquillity is a branch of the Captain James A. Lovell Federal Health Care Center (FHCC) and recruits may be taken there if needed.
If your recruit requires additional dental work, s/he will get that on board the USS Osborne. (See http://www.lovell.fhcc.va.gov/locations/USSOsborne.asp.)
BTW, a great thing to do while your Recruit is in BC is to change your Username to include your recruit's Ship and Division number, but not if s/he is in an 800 division. (Check out OPSEC and PERSEC (Making Changes To Your Profile) for more on making this change and other changes you may want to make.) If others know the Division number and PIR group, they can identify you faster. Although including the Ship and Division number in your Username helps to find others in the same division, if the Chiefs and/or RDC's are checking out the site, this draws attention to the division number, so you may want to consider removing that from your Username once you have made contact with others with loved ones in the same division.
There is more information on FAST, FIT, PASS, RCU, SEPS, and the THU and much more in What does ??? mean? (A Guide to Navy Abbreviations and Terminology).
The above information is provided by lemonelephant, the mom of a Sailor
The PDF documents with The Story and History of the ships are thanks to Craig.