Where can I get a drain plug for a 1968 Rich-line 16 foot aluminum boat?

You can find a drain plug for a 1968 Rich-line 16-foot aluminum boat at marine supply stores, or you can check online retailers like Amazon or eBay. Additionally, specialty boat parts websites may carry the specific parts you need. If you're looking for OEM parts, contacting Rich-line directly or visiting local boat salvage yards might also yield results.