Can i deduct a boat for fishing

Yes, under Section 179 you can claim the boat as a business expense (if used more than 50% for business). You must claim Section 179 deductions for equipment in the tax year that the equipment was "placed in service" - meaning when the boat is ready and available. 

Please be advised: If you chose not to take the full Section 179 deduction, you may be able to take a one-time special allowance depreciation. After entering the percentage of the 179 deductions, the system will move you to the special allowance depreciation option. Please note that not every state follows the federal rules for depreciation.

 To enter the boat to receive the 179 deduction, please follow the steps below.

1. Select the Business tab
2. Choose Explore on my own or I'll choose what to work on  (if it comes up)
3. Next, select Business Income and Expenses - Click the Start or Update button
4. If you've already entered the information for the business, click Edit next to the business name
5. On the  business summary screen, select Business Asset.
6. Walk through the interview questions and enter the information regarding the boat. 

For more information, please see the information below.

https://ttlc.intuit.com/replies/3302228

No, not directly. If the boat is used for fishing by the business to produce income, then it's a business asset. It's listed as such in the Business Assets section and it's cost gets depreciated over time.