Chuteman, you'll find each lender has different rules not just different rates, so it will pay to shop around. But if too many lenders do credit checks on you in a short time--that hurts your credit rating too! So, by all means ask them about their polciies and terms but don't ask for an actual pre-approval or credit check until you are gong to
contract.
Contracts can be written as "subject to
survey and finance approval" and brokers know that sometimes the financning won't happen, that's not unusual.
Among the differences, some lenders won't touch a boat more than 20 years old, or 30. Will require a
survey, any survey, or a particular survey. Might have costs besides the obvious finance rate--ask if there are *any* other costs. Probably will require loss
insurance, ask them how much of what kind. And they'll ask what or when you have owned a boat before, some won't do first-timers above a certain boat size/age/cost either.