Go to eq atlas look up TD, there is a dock where the boat stops and you can get back on.....if you fall off when a boat is not moving any other time you can ride the bow or rudder.
-5000, -3000 is where you need to head.
http://www.eqmacwiki.com/eqatlas/timorousdeepmap.html
make a /loc button and increase that swim skill.