Charisma, Understand the challenge. I live 250mi from the boat. While a H26 is a production boat and all used the same (or at the least similar) equipment, there is no telling what changes a previous owner may have made to enhance the boating experience. So telling you, My 2015 boat uses a "XX22XX" bulb may be of little help should your 1987 boat be using a "YY11YY"" design.