What size is it, and how many threads per inch?
Although deck fills are labeled 1.5", most are actually 1.5" barbed x 1.25" threaded. However, there are a few that really are 1.5 x 1.5...so you need to measure.Then count the number of threads per inch... Most older boats will have 16, while the only thing you can find on the shelves any more is 11--which is prob'ly why you can't just pick up a replacement from WM, B/US etc. I had the same problem on my own boat...the waste fitting cap--which cannot have a chain--went over the side. I finally had to replace the whole deck fill...NObody makes 11 tpi fittings any more, and NObody has replacement caps for 'em. That's the bad news.The good news is--I just happen to have found 2 "waste" fittings and a water fitting, along with 4 replacement caps while cleaning out what used to be my warehouse last week. They're gorgeous 316 investment cast stainless, and so are the caps, and the all have deck plate keys. If you want one of 'em, you can have it--and an extra cap--for the cost of shipping 'em from Atlanta to you. You'll still have a bunch of labor you'll be kicking yourself for letting happen, but at least it won't cost you $30 for a new fitting.Same offer goes to anyone else who needs a "waste" deck fitting. E-mail me and they're yours "while supply lasts."