Don't boats depreciate over 10 years? The asset category in TT is set to 7.

Yes, the class life of a boat is 10 years under MACRS.  

Here is a link to the IRS Publication 946 Appendix B where the class life tables can be found. 

To enter the information in TurboTax, you will need to go through the following steps:

• Start from the Schedule C section of your return until you get to the Assets/Depreciation section.
• Proceed to the point where you are adding an asset on the page titled Describe This Asset.
• Choose the last option on the list, Intangibles, Other Property, then click Continue.
• On the next page titled, Tell Us a Little More, select Other asset type, then click Continue.
• Enter the detailed information about the asset:  description, cost, date purchased or acquired.  Click Continue.
• Move forward with additional details on the next screen, then click Continue.
• Select the appropriate Asset Class, then click Continue.
• Choose the MACRS Convention (200% declining balance), then click Continue.
• Answer the question regarding Listed Property, then click Continue.  There may be some additional background questions as well, keep going.
• Finally, you will see an Asset Summary screen with the current year depreciation amount listed.  There is also a check-box here to Show Details.  This will open a full description for the asset so you can verify that has been entered properly.  If not, you can choose to go Back and re-enter the data that needs to be changed.