You guys that can read Hull numbers decipher this one.

CRT281931076

I know its Cigarette Racing Team, and 1976. What do the others stand for?

Prior to 1980 the 9th digit was a M followed by a the year and month.

mmmsssssmddy
mmm = Manufacturer US Identification Code
sssss = Hull Serial Number
m = Indicates year format
dd = Year of production
y = Month of production with

Aug = A
Sep = B
Oct = C
Nov = D
Dec = E
Jan = F
Feb = G
Mar = H
Apr = I
May = J
Jun = K
Jul = L

After 1980,

mmmhssssddyy

Where:

mmm = Manufacturer US Identification Code
h = Model description
ssss = Hull Serial Number
dd = Date of Manufacture -
Where A to L = Month starting with January and then
the last two digit of the year.
yy = Model Year

Despite the above, the format you gave seems to deviate from this.

mine reads crt-28-175-04-76

crt = cigarette
28 = model 28 (ss)
175 = 175 boat built ?
04 = 4th boat built in 1976 ?
76 = year built

just my thoghts!