Ship Design Codes Used by the U.S. Maritime Commission ~ Shipbuilding History

Ship Design Codes Used by the U.S. Maritime Commission

The ship design classification system used by the U.S. Maritime Commission (MARCOM) employs the structure: C4-S2-A4

where	represents
C	ship type, as shown in the first table below
4	ship size, as shown in the first table below
S	propulsion system, as shown in the second table below
2	passenger capacity and number of propellers, as shown in the second table below
A	sequential letter indicating the specific design for this type of ship
4	sequential number indicating the specific revision to this design

Type Code	Size Code (in ranges of LWL)
		1	2	3	4	5	6	7
B	barge	up to 100	100 to 150	150 to 200	200 to 250	250 to 300	300 to 350	350 to 400
C	freighter	up to 400	400 to 450	450 to 500	500 to 550	550 to 600	600 to 650	650 to 700
G	Great Lakes Cargo ship	up to 300	300 to 350	350 to 400	400 to 450	450 to 500	500 to 550	550 to 600
H	Great Lakes Passenger ship	up to 300	300 to 350	350 to 400	400 to 450	450 to 500	500 to 550	550 to 600
IB	Integrated Tug-barge	up to 200	200 to 300	300 to 400	400 to 500	500 to 600	600 to 700	700 to 800
J	Inland Cargo ship	up to 50	50 to 100	100 to 150	150 to 200	200 to 250	250 to 300	300 to 350
K	Inland Passenger ship	up to 50	50 to 100	100 to 150	150 to 200	200 to 250	250 to 300	300 to 350
L	Great Lakes Bulker (Laker)	up to 400	400 to 450	450 to 500	500 to 550	550 to 600	600 to 650	650 to 700
LG	Liquid Gas Carrier	up to 450	450 to 500	550 to 600	600 to 650	650 to 700	700 to 750	750 to 800
N	Coastwise Cargo ship	up to 200	200 to 250	250 to 300	300 to 350	350 to 400	400 to 450	450 to 500
OB	Oil/Bulk/Ore Carrier	up to 450	450 to 500	500 to 550	550 to 600	600 to 650	650 to 700	700 to 800
P	passenger	up to 500	500 to 600	600 to 700	700 to 800	800 to 900	900 to 1000	1000 to 1100
Q	Coastwise Passenger ship	up to 200	200 to 250	250 to 300	300 to 350	350 to 400	400 to 450	450 to 500
R	Refrigerated Cargo ship	up to 400	400 to 450	450 to 500	500 to 550	550 to 600	600 to 650	650 to 700
S	Special Purpose ship	up to 200	200 to 300	300 to 400	400 to 500	500 to 600	600 to 700	700 to 800
T	tanker	up to 450	450 to 500	500 to 550	550 to 600	600 to 650	650 to 700	700 to 800
U	ferry	up to 100	100 to 150	150 to 200	200 to 250	250 to 300	300 to 350	350 to 400
V	tugboat	up to 50	50 to 100	100 to 150	150 to 200	200 over

Notes:

Larger ships have size codes that are incrementally larger.
Liberty ships were EC2, the E being for Emergency.
Victory ships were VC2, the V being for Victory.

Propulsion Code		Notes:
S	Steam	The letter code alone indicates a single-screw ship that carries 12 or fewer passengers.
M	Motor	The suffix T indicates a twin-screw ship that carries 12 or fewer passengers.
SM	Steam and motor	The suffix TR indicates a triple-screw ship that carries 12 or fewer passengers.
SE	Turbo-electric	The suffix QR indicates a quadruple-screw ship that carries 12 or fewer passengers.
ME	Diesel-electric	The suffix 1 indicates a single-screw ship that carries more than 12 passengers.
G	Gas turbine	The suffix 2 indicates a twin-screw ship that carries more than 12 passengers.
GE	Gas turbine-electric	The suffix 3 indicates a triple-screw ship that carries more than 12 passengers.
N	Nuclear	The suffix 4 indicates a quadruple-screw ship that carries more than 12 passengers.