Prow Left Aes Grave Sextans, Cr 36/5

Prow Left Cast Sextans

Cr 36/5, 225 – 217 BC

I bought a prow left Sextans in the NAC auction last weekend. It is the 3rd prow left coin I have bought in less than a year, and the most expensive. I live in the US. The coin is across the Atlantic Ocean. I am sure it will take a while to get here, so I am using NAC's pictures.
The largest issue of cast bronze coins by Republican Rome had the prow (business end) of a warship on the reverse. Most were prow right. I do not know why some prows were pointed left, but there were enough prow left coins that Haeberline put then into 3 groups. Crawford followed suite and had three groups also:

• First Prow Left cast coins, 225 - 217 BC, wt std As = 270 grams - Cr 36: 1 - As; 2 - Semis; 3 - Triens; 4 - Quadrans; 5 - Sextans
• Second Prow Left cast coins, 217 - 215 BC wt std As = 132 grams - Cr 38: 1 - As; 2 - Semis; 3 - Triens; 4 - Quadrans; there were struck Sextans, Uncia, Semuncia and Quartuncia coins in this group. 
• Third Prow Left cast coins, 215 - 212 BC wt std As = between 132 and 54 grams - Cr 41: 1 - Decussis; 2 - Quincussis; 3 - Tressis; 4 - Dupondius; 5 - As; 6 - Semis; 7 - Triens; 8 - Quadrans; there were struck Semis, Triens, Quadrans, Sextans, Uncia and Semuncia coins in this group. 

I find it interesting that Crawford put three series of coins in a short time window of 225 to 212 BC. The weight ranges for the coins overlap. All of the cast Sextans were in the first group.

Roman Republic Cast Sextans circa 225-217, Æ

Obv - Head of Mercury l.; below, two pellets.

Rev - Prow l.; below, two pellets.

46.23 grams = 277 gram equivalent Ass

24 mm – this looks wrong, most on line are 30+

12 h – most of the cast coins I have seen are medal turn, or the obverse and reverse have the same orientation. A few are orientated coin turn, 6h. Even less have 3h or other orientations.

Brown green patina and very fine

Very rare (seller's words) – I found 10 examples on line, including mine.

Crawford 36/5, wt std = 270 grams

Aes Grave 23

Sydenham 82

Vecchi 92

Thurlow-Vecchi 62, wt std = 256 grams

RBW –.

Historia Numorum Italy 341.

Haeberlin p 55 – 56, plate 22, 17 – 20; wt range 34 – 54 grams