I am assuming you are in Marleybone so here's some advice. You can buy a Marleybone ship at the isle of dogs docks for 50k gold, you must be level 52. For that ship you can get some Marleybone gear at the bazaar and the lowest level items for a royal navy ship is level 24. Hope this helps
This boss ship drops quite a few nice items that will help you make your ship stronger.
Also - remember you can use your Yum Potion to heal during a nautical battle, so that the enemy doesn't board. By sinking ships you can bring up your nautical level faster, as well as get Scrip and ship equipment drops.
If you need help, my witchdoctor, Bridget Brewster, is currently farming The Hart of Gold for scrip, so look for her in Avery Realm.