You should have 1 million plus in an umbrella policy!
I was once moored next to a brand-new 50' expedition trawler in Fisherman's Terminal. A maritime lawyer had it commissioned and built. As we chatted the standard boat neighbor chat, he asked me what my liability policy was. Unusual question, and a little intimidating coming from a lawyer on a $2m yacht, but ok ..
I told him I had a $1m aggregate policy. His quote, I'll never forget it -
"Two million is the new one million. I can make anything go away with two million to work with."