It is true that a boat can be considered as a second home. But getting a home loan for a boat and getting tax benefits for living on the boat are two separate issues.
Getting a home loan for a boat actually means taking a second mortgage or a home equity loan and using it to buy a boat. The home would have already been purchased by taking a mortgage, which is the first mortgage. The homeowner can use his equity in the home - the mortgage amount yet to be paid deducted from the value of the home – to take a home equity loan or a second mortgage. This kind of loan is usually taken for home improvement like redoing the home. Some people also use this loan to buy a car or a boat or even to go on a holiday.
Even if a person is actually using the boat as a second home, he cannot claim any tax benefits if he has used a home equity loan to fund the purchase. This is because one of the conditions for claiming tax benefits is that the boat should be the collateral.
A boat is considered as a second home of a person if it has a designated cooking area, sleeping area and a bath room. It should be noted that the person need not actually live on the boat. If a loan has been taken to purchase such a boat with the same boat as collateral, then the boat owner can get the same tax benefits for the interest paid as he gets on the mortgage payments of his home.
So, one cannot get a home loan for a boat. All one can do is take a home equity loan and use the proceeds to buy a boat. On the other hand, if a boat qualifies as a second home, the loan interest paid would be tax deductible.