I put a bunch of money into trying to get a second income work going

[Oucymichelle]

How do I claim losses from trying to get a commercial fishing boat in shape to fish to make money - which failed. Ended up having to give the boat away and eat all the money I put out for repairs, traveling back and forth and my time. 

[RSUMan]

The key factor is whether you were "in business" while working on the commercial fishing boat.

I am assuming this was your business alone and that you would file as a sole proprietorship on Schedule C.  You would enter all the expenses you incurred.  The commercial fishing business would show a loss for 2023.