The boat should be scored OCS (on course side). Score is one plus number of registered boats (same as DNS, DNF anyway). Refer to Appendix A of RRS,
http://www.ussailing.org/rules/If a racing rule is broken, the skipper must either retire or take the alternate penalty (360 turn in most cat races).
Join US Sailing at
http://www.ussailing.org/membership/indivmem.htm