I am trying to depreciate my boat for my boat rental business, how do i do that?

I assume you will be filing Schedule C for the business of renting out the boat. 

Schedule E, which reports property rentals would not be the proper place since this will not be passive income. Passive income would be "you hand someone the keys and they send you a check each month".  I assume you are more involved than that. 

If my assumptions are correct, set up the business if this 2024 was the first year. 

Once that's done, scroll down to "Business Assets" and scroll down to "Assets Being Depreciated".

(You may need to go back to Business Income and Expenses, then click the business name on that list)

Select "Tools, Machinery, Equipment, Furniture"

Select "General purpose tools..."

Continue and enter the information the program asks for.

You will need to keep a log as to the business use and personal use and enter that percentage each year if it fluctuates year to year.

(the business depreciation will be calculated on that percentage)

Make your selection of the depreciation method you wish to use. 

The first option "Spread over several years will take a portion each of 7 years, since a boat has a 7 year life. 

You'll also have other options, such as a Section 179 Deduction and/or the special (bonus) depreciation.

If you choose either of those, be aware of how they work. Section 179 cannot create a business loss and Bonus Depreciation is limited and may need to be carried forward in year 8.

Please see IRS Pub 946

Enter your expenses (such as fuel) directly under the "Business Expenses" section and enter only the share that is attributed to the business. If you have expenses such as marina rent, you need to divide those expenses between business and rental and only report the business portion.

Keep in mind that the day you sell the boat, you most probably will need to deal with "depreciation recapture". 

Depreciation Recapture occurs when the asset is sold for more than the "Adjusted Basis". The adjusted basis is your cost less the depreciation taken (or could have been taken, so you don't have a choice to not claim)

If you buy a boat  for 50,000, take 40,000 depreciation over the years and sell it for 25,000, you would have 15,000 depreciation recapture. 

I advise you keep a copy of the depreciation schedule each year which will be generated when you do your tax return, but does not print unless you select it.