Husk, rinse and dry tomatillos and broil or grill for about 10 minutes per side until soft and dark blisters develop. Cut onion half into several pieces and roast with garlic and chiles on a hot griddle or skillet (preferably cast iron) until well blackened. Peel onion and garlic and stem (and if desired for lower heat, seed) peppers.
Process tomatillos, onion, garlic, and peppers in a food processor until fairly smooth. Add honey and salt and process to incorporate, tasting and adjusting as needed. Add cilantro leaves and process until uniformly incorporated.
Serve on tacos, with chips, as a flavoring for soups, etc.
Make ahead and refrigerate or freeze for your offshore cruise.