Irish pound coin
The "Broighter Boat" issue for 2000.The Irish pound coin, which was introduced in 1990, remains the largest Irish coin introduced since decimalisation at 3.11 centimetres diameter and was 10 grams weight. The coin was almost the same in dimensions to the old penny coin that circulated before 1971, and was quite similar in diameter to, but thinner, than the half-crown coin.
During the early circulation of the coin, many payphone and vending machines which had been changed to accept the pound coin also accepted the old penny because of the similar size, the latter coin which was no longer legal tender and had little value to collectors. As a result losses accrued to vending machine operators due to the substitution of the penny coin and further costs were associated with updating the machines so they would no longer accept the penny.