7% is about as good as you'll find for a used boat, or really any recreational product for that matter.
Term depends on amount and age stipulations of the lender, but for $50K or so you should get 12-15 years if you want it.
They are all wanting more down, but with good credit you should be able to get 10% if you need to.
They will require a survey or nada value depending on the lender and type of craft.
Credit unions tend to be one of the best sources. If it's a high value, a bigger yacht, then a broker specialist can work to your advantage, their niche are the bigger loans, $150K and up.
I don't know if I would finance with BoatUS, but 6.99 for 12-15 is pretty darn good though. And they seem to have a really good insurance progam for boats, stated value and reasonable rates.
We bought ours with our heloc. It's at about 3.5% right now, but it's indexed to the prime rate so that could definitely change. :roll: