Suppose you take out a loan to buy your recreational vehicle (RV) or boat. Surprisingly, the vehicle or vessel may qualify as a “second home” for federal income tax purposes. In other words, you may be eligible to write off the interest on the loan as mortgage interest on your personal tax return. The IRS says that any dwelling place qualifies as a second home if it has sleeping space, a kitchen and toilet facilities. Therefore, the interest paid to buy an RV or boat that meets these requirements is tax-deductible under the mortgage interest rules. This applies to interest paid on acquisition debt of up to $1 million and home equity debt of up to $100,000.