I don't own a boat, is take this with a grain of salt, but I find if something works, and I'm comfortable with it and its still in decent shape, stick with it. I prefer to stay on the trailing edge of things because it is cheaper and at some point the law of diminishing returns starts to kick in. I'd stuck with that old girl, take good care of her and keep her in the best shape you can. I don't know what your estimated retail value is, but with a boat that old I can't imagine it would be worthwhile to sell that to fund a down payment on a loan for a depreciating investment. Just ride that old girl until she dies, and then find a nice lightly used boat that is loaded up for a price you can afford when she does finally give up. Just my 2 cents. Once again, not a boat owner, so I'm probably a little misguided.