Irwin 37 Mk IV

Irwin Yachts built boats of mediocre quality and finish and marketed them to buyers looking for as much boat as possible for the price. In every sense of the word, Irwin boats, of which the Irwin 37 is archetypal, are production boats. They were mass produced, carefully priced, simply advertised, and widely sold to a broad spectrum of customers. More than 600 Irwin 37s were sold between the time the boat went into production in 1971 and its demise in 1982. The fourth generation of Irwin 37 was built between 1977 and 1982.

The last version was designated the Mark V, representing the popular strategy of numbering the steps in the evolution of a design even though the changes may be minor.

Source: Practical Sailor