In my opinion thinking you are safe on a catamaran is like saying I know the gun isn't loaded. You are only as safe as whats surrounding you allows you to be. Here the weather can change with almost zero warning. If you haven't sailed in a storm or a serious blow then you don't belong offshore. If you are going to tether your self make sure you have a knife strapped to you to free yourself. Also make sure it goes around your chest and not your waist. Watch how well your main comes down everytime. If it snags find out where and fix it before you go out next. If you haven't righted your boat singlehanded; find out if you can. If you don't have a bag of spare everything and a tool to install it get one. If you are going to have a contact person on shore make sure they want to do it and understand its important they keep the phone with them turned on and the battery charged. Have a yellow life jacket. Carry some water and energy bars in case you have to spend the night away. Carry a compass as well as the normal survival gear.

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thom