Build a schooner instead, either put one large speed sail on it for solo or hire an npc and have a small handling sail on it too. If you go too far overweight with a ship it will slow it down, try and keep to a third of the total weight if you can. But when the ship levels you can always put points in ship weight. you need to be fast for the sotd, and a small handling sail will help you catch a breeze, whereas the large speed sail is just for speed. A sloop is just too small even for a solo player. you can put cannons on during or after building. If you do some fishing you get a small amount of gold and this will help you hire your first npc crew for the sails etc. Happy sailing.