Using a heavy worsted/bulky yarn and size 8 circulars or dpns. There is no gauge, sorry.

M1 = Make one purl
Kfb = Knit in the front and back of the same stitch
CL = Cable 2 k Front, 1P back
Slip two stitches to a cable needle and hold in the front, purl one, knit the two off your cable needle.
CR = Cable 1 P Back, 2 K Front
Slip one stitch to a cable needle and hold in the back of your work, knit two stitches, purl one off your cable needle.
Increases are on every second and fifth row.

Top of hat:
Cast on 8 sts
R1: K8
R2: (Kfb)8 16 sts
R3: K around
R4: K around
R5: (K2, M1, K2, M1)4 24 sts
R6: (K2, P1, K2, P1)4
R7: (K2, M1, P1, M1, K2, P1)4 32 sts
R8: (K2, P3, K2, P1)4
R9: (K2, P3, K2, P1)4
R10: (K2, P1, M1, P2, K2, M1, P1)4 40 sts
R11: (K2, P4, K2, P2)4
R12: (K2, P1, M1, P2, M1, P1, K2, P2)4 48 sts
R13: (K2, P6, K2, P2)4
R14: (K2, P6, K2, P2)4
R15: (K2, P1, M1, P4, M1, P1, K2, P2)4 56 sts
R16: (K2, P8, K2, P2)4
R17: (K2, P1, M1, P6, M1, P1, K2, P2)4 64 sts
R18: (K2, P10, K2, P2)4
R19: (K2, P10, K2, P2)4
R20: (K2, P1, M1, P8, M1, P1, K2, P2)4 72 sts
R21: (K2, P12, K2, P2)4
R22: (K2, P12, K2, M1, P1, M1, P1)4 80 sts
R23: (K2, P12, K2, P4)4
R24: (K2, P12, K2, P4)4
R25: (K2, P5, M1, K2, M1, P5, K2, P4)4 88 sts
R26: (CL, P4, K4, P4, CR, P4)4
R27: (P1, M1, K2, P3, CR, CL, P3, K2, P1, M1, P4 )4 96 sts
R28: (P2, CL, P2, K2, P2, K2, P2, CR, P6)4
R29: (P3, K2, P1, CR, P2, CL, P1, K2, P7)4
R30: (P3, CL, K2, P1, M1, P2, M1, P1, K2, CR, P7)4 104 sts
R31: (P3, M1, P1, SSK, K2TOG, P1, M1, P5, M1, SSK, K2TOG, P1, M1, P7)4
R32: (P3, M1, P16, M1, P7)4 112 sts
R33: P around
R34: P around
R35: (Kfb, K13, Kfb, K13)4 120 sts
R36: K around
R37: (Kfb, K14, Kfb, K14)4 128 sts
R38: P around
R39: P around (128 stitches)
For the following section, knit all rows decreasing 8 stitches evenly around every 2nd and 5th row. I typed up each row below in case you need the reference.
R40: (K2TOG, K14)8
R41: K around
R42: (K2TOG, K13)8
R43: K around
R44: K around
R45: (K2TOG, K12)8
R46: K around
R47: (K2TOG, K11)8
R48: K around
R49: K around
R50: (K2TOG, K10)8
R51: K around
R52: (K2TOG, K9)8
R53: K around
R54: K around
R55: (K2TOG, K8)8
R56: K around
R57: (K2TOG, K7)8
R58: K around
R59: K around

Band:
Knit 13 rows K2, P2 ribbing.
Bind off loosely.
If necessary, weaving elastic thread in the ribbed rows will allow for a snugger fit.
Weave in the ends and block, I used a dinner plate.

Note: You can adjust the number of decreases around you do to get the fit you want for your head.