ebay might be a source

Here is a link that might be useful: Single Slice Toaster (vintage)

I have a double oven range with a toaster option in smaller top oven. It is actually a broil selection with a timer that turns it off at the right time. Is your range small with a broil option? You can use broil for 2-3 min for toast. Just place the bread directly on the oven grill, set to broil and your done. Works for any type or thickness of bread, bagels, etc. I got rid of my toaster and have not looked back. Just time yourself for right toasting, which eventually becomes a norm smelling toasted bread ready. Enjoy living on your boat, what a great place to be.