Insurance is not required, but certainly advisable for a number of reasons. Back in 2004 I kept my boat in a rental Storage shed up on Rayburn and the shed burned down. There were I think 11 boats stored there of which only two were insured. Mine was one of the two that were insured. The guy who had the stall right next to mine had a brand new Champion with no insurance....Total loss,
The other reason is liability. No one goes out on the lake with the intention of hurting someone or getting hurt, but should it happen, are you prepared to lose everything you have? My advice is get insurance if the boat is not all that expensive, neither will the insurance be.
"The democracy will cease to exist when you take away from those who are willing to work and give to those who would not."
— Thomas Jefferson