College Boat Donation

I live in Rhode Island, and just started a new job at a boat yard. How would i go about figuring out how much I would make after all taxes are taken out…?

Can I deduct my registration fee for my 32′ boat? I know I can deduct the sales tax, and it’s paid in full. But I had to register it and can I deduct that?
I do not know how to tell what portion is PP tax and what is not…

CASUALTY LOSS (BUSINESS OR PERSONAL?) tax deductibility question

Assume an individual has a boat where he entertains clients.
(1) If the boat sinks and he qualifies for a Casualty Loss deduction under Sect 165, where is the authoritative literature that guides whether it is a business casualty loss or a personal casualty loss?
I have been searching the Code, common law, and publications.
The only thing I have found is under Publication 463, entertainment expenses that are subject to the 50% deduction.
(2)If the boat that the individual used to entertain clients was subject to the 50% limitation, would it also qualify the loss to be a business casualty loss?

(3) The boat sinks due to an “other casualty” and he is alone on the boat

Can anyone provide for me primary sources on how to view whether the boat can be a personal or business casualty loss? And if he obviously used the boat at times for personal and sometimes for business, where is the authoritative literature on this?

Thanks in advance!

Tax question—

My client donated a boat on August 1, 2003. He received an appraisal on the boat 1 week before for 395,000. After donating the property the charity sold the boat for 135,000 on August 8, 2003. IRS has disapproved the 395,000 and says the deduction can only be 135,000 and want 100,000 right away. Any help regarding this issue would be greatly appreciated.